Fe-Mn-Cu-Ce/Al2O3 as an efficient catalyst for catalytic ozonation of bio-treated coking wastewater: Characteristics, efficiency, and mechanism

Run Yuan; Yihe Qin; Can He; Zichen Wang; Lu Bai; Hong Zhao; Zijian Jiang; Lingyao Meng; Xuwen He

doi:10.1016/j.arabjc.2022.104415

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Original article

01 2022

:16;

104415

doi:

10.1016/j.arabjc.2022.104415

Fe-Mn-Cu-Ce/Al₂O₃ as an efficient catalyst for catalytic ozonation of bio-treated coking wastewater: Characteristics, efficiency, and mechanism

Run Yuan^{^a}, Yihe Qin^{^a}, Can He^{^b}, Zichen Wang^{^a}, Lu Bai^{^a}, Hong Zhao^{^a}, Zijian Jiang^{^a}, Lingyao Meng^{^a}, Xuwen He^{^a,⁎}

a Department of Chemical and Environmental Engineering, China University of Mining and Technology (Beijing), Beijing 100083, China

b Institute of Resources and Environment, Beijing Academy of Science and Technology, Beijing 100089, China

⁎Corresponding author at: Department of Chemical and Environmental Engineering, China University of Mining and Technology (Beijing), Beijing 100083, China. hexuwen0708@163.com (Xuwen He)

Received: 2022-8-21, Accepted: 2022-11-8,

Disclaimer:
This article was originally published by Elsevier and was migrated to Scientific Scholar after the change of Publisher.

Peer review under responsibility of King Saud University.

Abstract

Abstract

It is important to develop a catalyst that has high catalytic activity and can improve the degradation efficiency of refractory organic pollutants in the catalytic ozonation process. In this study, Fe-Mn-Cu-Ce/Al₂O₃ was synthesised via impregnation calcination for catalytic ozonation of bio-treated coking wastewater. The physical and chemical characteristics of the catalysts were analysed using X-ray diffraction (XRD), X-ray fluorescence spectrometry (XRF), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and Brunauer–Emmett–Teller nitrogen adsorption–desorption methods. The effects of catalyst dosage, pH, and reflux ratio on the degradation efficiency of wastewater were examined in laboratory-scale experiments. The chemical oxygen demand (COD) removal rate of bio-treated coking wastewater was estimated to be 52.76 % under optimal conditions. The experiments on the catalytic mechanism demonstrated that the surface hydroxyl formed by the Lewis acid sites on the surface of the catalyst can react with ozone as the active site forming the active oxygen (·OH, ·O₂^–, and ¹O₂), thereby efficiently degrading the organic pollutants in coking wastewater. Furthermore, a pilot-scale experiment on the catalytic ozonation of bio-treated coking wastewater was carried out using an Fe-Mn-Cu-Ce/Al₂O₃ catalyst, while the effects of the initial pollutant concentration, ozone concentration, and gas flow on the COD removal rate were studied on a pilot scale. It was found that the COD removal rate of the wastewater was ∼ 60 % under optimal parameters. After the treatment, the wastewater steadily reached the coking wastewater discharge standard (COD < 80 mg/L), while the operating cost of catalytic ozonation reached ∼ 0.032$/m³, thereby paving the way toward economic engineering applications. The COD degradation kinetics in the bio-treated coking wastewater followed pseudo-second-order kinetics. Three-dimensional fluorescence and gas chromatography–mass spectrometry revealed that macromolecular organic pollutants in the bio-treated coking wastewater were greatly degraded. In summary, Fe-Mn-Cu-Ce/Al₂O₃ exhibited good reusability, high catalytic activity, and low cost and has a wide application prospect in the treatment of coking wastewater.

Keywords

Fe-Mn-Cu-Ce/Al2O3

Catalytic ozonation

Coking wastewater

Catalytic mechanism

Pilot-scale study

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Nomenclature

XRD: X-ray diffraction spectrometry
XRF: X-ray fluorescence spectrometry
XPS: X-ray photoelectron spectroscopy
SEM: Scanning electron microscopy
COD: Chemical oxygen demand
·OH: Hydroxyl radical
·O₂^–: Superoxide radical
¹O₂: Singlet oxygen
min: minutes
CO system: Catalytic ozonation system
EPR: Electron paramagnetic resonance
GC–MS: High-performance gas chromatography–mass spectrometry
BET: Brunauer–Emmett–Teller nitrogen adsorption–desorption methods
TDS: Total dissolved solids
CA: Fe-Mn-Cu-Ce/Al₂O₃
SCA: Catalyst carrier
EDS: Energy-dispersive X-ray spectroscopy
pHpzc: the pH point of zero charge
TBA: Tertiary butanol
pBQ: p-benzoquinone
FFA: furfuryl alcohol
BJH: Barret-Joyner-Halenda methods
DOC: Dissolved total organic carbon
FTIR: Fourier transform–infrared spectroscopy
3D-EEM: Three-dimensional fluorescence spectrum
UV₂₅₄: Absorbance of some organic substances in water under 254 nm ultraviolet light

1 Introduction

Coking wastewater is composed of wastewater generated at each production node in the coal coking process, mainly including ammonia steaming wastewater, condensate water, desulphurisation wastewater, coke quenching wastewater, and other production water in the coking process (Yuan et al., 2022). It is a typical high concentration organic industrial wastewater that is difficult to degrade. Coking wastewater contains numerous harmful substances, such as phenols, polycyclic aromatic hydrocarbons, nitrogen heterocyclic organic pollutants, sulphur heterocyclic organic pollutants, aromatic hydrocarbons, fatty hydrocarbons, and other organic pollutants. In addition, it contains large amounts of sulphide, cyanide, fluoride, and other inorganic pollutants (Hu et al., 2022, Qin et al., 2022). It is challenging to treat coking wastewater owing to its large volume, complex water quality, difficult biochemical degradation, and high toxicity. If coking wastewater is discharged arbitrarily without proper treatment, it will cause dangerous health problems, such as cancer, and trigger severe environmental damages, such as death of aquatic organisms and soil salinisation (He et al., 2022, Qin et al., 2022, Wang et al., 2022 ). China had promulgated a new coking wastewater discharge standard, whereby various water quality indices of coking wastewater discharge were introduced (China 2012). Consequently, high requirements for coking wastewater discharge were proposed. Of the various water quality indices of coking wastewater, it is particularly challenging to meet the wastewater discharge standard (COD < 80 mg/L) for the COD of bio-treated coking wastewater (Zhang et al., 2021).

To ensure that the COD of coking wastewater after biochemical treatment meets the wastewater discharge requirements, an advanced treatment process is usually used to further remove the residual organic pollutants in coking wastewater. Advanced treatment processes, such as adsorption, coagulation, membrane separation, biochemical, and advanced oxidation processes, have been widely used for the treatment of coking wastewater owing to their high COD removal efficiency (Tamang and Paul 2022; Wang et al., 2022; Zhu et al., 2022 ). However, biochemical processes are limited owing to issues, such as a long processing time and its degradation limit; the adsorption process has problems, such as high cost and incomplete mineralisation; the membrane separation process has problems, such as membrane pollution and high requirements for influent water quality; and the coagulation process has problems, such as serious secondary pollution (Yuan et al., 2022). Compared with the above processes, the advanced oxidation process has been widely concerned due to high stability, good mineralisation effect, and high treatment efficiency (Pal and Kumar 2014; Coha et al., 2021).

Nowadays, numerous advanced oxidation processes are used for degrading organic pollutants including the Fenton (Tyagi et al., 2020; Yang et al., 2022), electrochemical (Wang et al., 2021), photocatalytic (Liu et al., 2022), ozone (Sun et al., 2020), wet oxidation (Quintanilla et al., 2019), enhanced peroxymonosulphate (Yang et al., 2022), microwave catalytic (Lin et al., 2022) and ultrasonic processes(Gao et al., 2022). The Fenton process is limited by the large dosage, whereas the wet oxidation process has the problem of high cost and harsh reaction conditions. Most of the other advanced oxidation processes mentioned above are basically in the stage of laboratory scale research, and their application in practical industrialisation needs further exploration. Compared with other advanced oxidation processes, the ozone process has attracted substantial attention of researchers worldwide because of its low cost, good industrial application prospect, and environmental friendliness (Wang and Zhuan 2020). However, single ozone processes have some setbacks, such as ineffective solubility and selective degradation. To alleviate these setbacks, researchers normally use ozone-based advanced oxidation processes, such as heterogeneous ozone catalytic, ozone/persulfate, ozone/ultraviolet, ozone/Fenton, ozone/electrochemical, and ozone/ultrasonic processes (Liu et al., 2021, Pang et al., 2022). Notably, while most ozone-based advanced oxidation processes can only be applied at the laboratory scale, some scholars noted that heterogeneous catalytic ozone oxidation processes can potentially open more promising engineering applications (Nakhate et al., 2019, Chen et al., 2021).

As catalytic ozonation can markedly improve the utilisation rate of ozone and degradation efficiency of organic matter, it has been widely used in various wastewater treatment processes (Wang and Bai 2017, Yuan et al., 2020). To date, numerous metal oxides are used as catalysts for the treatment of organic wastewater via catalytic ozonation. In this context, alumina has been widely studied because of its low cost, good catalytic activity, and stability (Sani et al., 2019, Faghihinezhad et al., 2022, Liang et al., 2022 ). Moreover, researchers usually load one or more active metals onto alumina to strengthen the catalytic activity of the catalyst (Qu et al., 2004, Shao et al., 2022). Among the numerous transition metals, iron, manganese, copper, and cerium are often used to enhance the catalytic activity of catalysts and improve the removal efficiency of organic pollutants owing to their excellent electronic conversion ability and potential high catalytic activity (Chen and Wang 2014, Li et al., 2020, Reddy et al., 2021, Shao et al., 2022 ). In addition, compared with some precious metals (such as platinum and palladium), iron, manganese, copper, and cerium have lower costs and better industrial application prospects (Chen et al., 2015, He et al., 2020). In general, alumina supported by polymetallic oxides exhibits higher catalytic activity than alumina supported by a single metal oxide or bimetallic oxide (Tong et al., 2010, Chen et al., 2017). Thus far, several key studies on the catalytic ozonation of different types of organic wastewater have been conducted using polymetallic-supported alumina as a catalyst, showing that catalytic ozonation systems can increase the removal efficiency of organic pollutants by approximately 20 % to 35 % compared to single ozonation systems (Li et al., 2020, Zhao et al., 2021, Ma et al., 2022 ). Despite these promising results, there were only few studies on the catalytic oxidation of bio-treated coking wastewater with an alumina catalyst loaded with iron, manganese, copper, and cerium. Moreover, many studies on the degradation of organic compounds via catalytic ozonation have been conducted at the laboratory scale, while the practical engineering applications are limited.

In this study, a Fe-Mn-Cu-Ce/Al₂O₃ catalyst was prepared, characterised, and used for the catalytic ozonation of bio-treated coking wastewater. To this end, the effects of different parameters on the catalytic performance of the Fe-Mn-Cu-Ce/Al₂O₃ catalyst (a) were analysed, and the catalytic mechanism for the degradation of organic pollutants in bio-treated coking wastewater (b) was elucidated. Furthermore, (c) a pilot-scale test of the catalytic ozonation of bio-treated coking wastewater was conducted, (d) the reusability of the catalyst alongside the operation cost of the pilot-scale test were both evaluated, while the degradation kinetics and removal behaviour of organic pollutants in bio-treated coking wastewater were elucidated.

2 Materials and methods

2.1

2.1 Experimental materials

The experimental reagents were of analytical purity and were purchased from Shanghai Aladdin Biochemical Technology Co., ltd. The bio-treated coking wastewater was a secondary biochemical effluent obtained from the Inner Mongolia Province (China).

2.2

2.2 Preparation of catalysts

The Fe-Mn-Cu-Ce/Al₂O₃ catalyst was prepared using the dipping-calcination method using spherical γ-Al₂O₃ as the carrier, whereas γ-Al₂O₃ was purchased from Shandong (China). Its particle size was 2–4 mm. First, the carrier was washed with deionised water and dried at 105 °C for 10 h. The dried carrier with the same volume was dipped in a mixed solution containing 0.05 mol/L Fe(NO₃)₃, 0.05 mol/L Mn(NO₃)₂, 0.05 mol/L Cu(NO₃)₂, and 0.05 mol/L Ce(NO₃)₃ for 24 h. These steps were repeated twice to acquire the catalyst. The modified carriers were dried at 105 °C for 10 h and calcined at 500 °C for 6 h.

2.3

2.3 Analytical methods

Text S1 summarises the specific parameters of XRD, XRF, XPS, SEM, Brunauer–Emmett–Teller (BET) nitrogen adsorption–desorption isotherms, electron paramagnetic resonance (EPR), gas chromatography–mass spectrometry (GC–MS), three-dimensional fluorescence (3D-EEM), and Fourier transform–infrared spectroscopy (FTIR).

The COD concentration of the coking wastewater was determined using American HACH reagents according to the fast digestion-spectrophotometric method (He et al., 2022). The total dissolved organic carbon (DOC), conductivity, total dissolved solids (TDS), colour, turbidity, zeta potential, and pH were analysed using standard methods (AHA-AWWA-WEF 1998). The dissolved ozone concentration and gas-phase ozone concentration were determined by the Indigo method and iodometric titration, respectively (Liu et al., 2019).

The COD degradation efficiency was calculated using Eq. (1).

(1)

T = 1 - {COD}_{t} / {COD}_{0}

where T is the COD degradation efficiency, [COD]_t (mg/L) is the COD value of wastewater at different reaction times, and [COD]₀ (mg/L) is the initial COD value of the wastewater.

The calculation method of reflux ratio is represented in Eq. (2):

(2)

R = V O W / T W V

where R is the efficiency of the reflux ratio and VOW(m³) is the volume of water pumped out by the circulating pump for 1 h; TWV(m³) is the volume of treated water.

The operation cost was using Eq. (3):

(3)

OC = \frac{C [O_{3}] \times G f \times t \times 14 \times 0.19}{T W V \times 10^{6}}

where OC(USD/m³) is the operation cost and C[O₃] (mg/L) is the ozone concentration. Gf(L/min) is the ozone gas flow rate, and t(min) is the reaction time. The cost of ozone production from engineering experience is 14 (kWh/kgO₃), and the price of electricity for the industry is approximately 0.19 (USD/kWh) (Cai et al., 2020, Chen et al., 2021); The volume of treated water is TWV(m³).

The ozone utilization rate is determined as:

(4)

U = \frac{O_{3 [i n]} - O_{3 [o u t]} - O_{3 [d]}}{O_{3 [i n]}}

where U is ozone utilisation, O_3[in] is the inlet ozone concentration, O_3[out] is the outlet ozone concentration, and O_3[d] is the dissolved ozone concentration.

The reaction kinetics of removing organic pollutants from coking wastewater by catalytic ozonation can be expressed by Eq-s (5) and (6):

(5)

\frac{d {[COD]}_{t}}{dt} = K_{A} \times [O_{3}] \times {[COD]}_{t}^{n} + K_{B} \times [\cdot O H] \times {[COD]}_{t}^{n}

(6)

\frac{d {[COD]}_{t}}{dt} = (K_{A} \times [O_{3}] + K_{B} \times [\cdot O H]) \times {[COD]}_{t}^{n} = K \times {[COD]}_{t}^{n}

where K_A and K_B are the kinetic reaction constants of ozone and the ·OH degradation of COD, respectively, while n is the reaction order of the COD degradation kinetics. Notably, when n = 1 and 2, the reaction kinetics followed pseudo-first-order and pseudo-second-order reaction kinetics, respectively. When n = 1 or 2, Eq. (6) can be converted into Eqs (7) and (8), respectively, as shown below:

(7)

Ln \frac{{[C O D]}_{t}}{{[C O D]}_{0}} = k_{1} \times t + C

(8)

{[C O D]}_{t}^{- 1} - {[C O D]}_{0}^{- 1} = k_{2} \times t + C

where k₁ and k₂ are the pseudo-first-order and pseudo-second-order reaction kinetics, respectively and C is a constant.

2.4

2.4 Experimental system

Fig. 1 and Figure S1 show the pilot scale catalytic ozonation system and laboratory scale catalytic ozonation system, respectively. The reaction system includes an oxygen cylinder, ozone generator, ozone concentration detector, catalytic ozonation reactor, and tail gas treatment device. Pure oxygen was used as the gas source in the ozone generator. An ozone concentration detector was applied to quantify the concentration of the generated ozone. Ozone entered from the bottom of the reactor and reacted with the wastewater in the reactor. Residual ozone in the reactor was collected and treated. A circulating pump was used to strengthen the COD degradation efficiency. The treated water volumes at the laboratory scale and pilot scale were 2 and 300 L, respectively. The operating parameters are changed according to the specific experimental conditions.

Schematic diagram of catalytic ozonation reaction system in pilot scale.

Both pilot-scale and laboratory-scale tests were performed with a series of batch experiments. During the pilot scale catalytic ozonation experiment, 3–5 batch experiments were conducted on average every day, and the catalyst was not further treated. In addition, unless otherwise specified, the hydraulic retention time of each pilot scale catalytic ozonation experiment was 2 h.

3 Results and discussion

3.1

3.1 Comparison of COD removal efficiency by different reaction systems

As shown in Fig. 2, the COD removal efficiencies with different reaction systems were in the order of ‘adsorption system’ (6.9 %) < ‘single ozone oxidation system’ (27.08 %) < ‘CO system with Al₂O₃′ (38.45 %) < ‘CO system with Fe/Al₂O₃′ (46.38 %) < ‘CO system with Fe-Mn /Al₂O₃′ (49.02 %) < ‘CO system with Fe-Mn-Cu/Al₂O₃′ (51.96 %) < ‘CO system with Fe-Mn-Cu-Ce/Al₂O₃′ (54.97 %). The removal efficiency of COD from coking wastewater by catalyst adsorption was only 6.9 %, which indicated that the adsorption effect is not the main reason for the removal of COD from coking wastewater. Compared with the single ozonation system (27.08 %), different catalytic ozonation systems can greatly increase the removal efficiency of COD from coking wastewater after biochemical treatment, which indicated that the carrier and various catalysts have certain catalytic activity. As Fe, Mn, Cu, and Ce were loaded onto the carrier, the removal efficiency of COD in coking wastewater increased gradually, which indicated that iron oxide, manganese oxide, copper oxide and cerium oxide have a synergistic effect, and the loading of Fe, Mn, Cu and Ce can further enhance the catalytic performance of the catalyst. Among catalysts, Fe-Mn-Cu-Ce/Al₂O₃ showed the best catalytic performance in the process of removing COD from coking wastewater after biochemical treatment.

COD removal efficiency of bio-treated coking wastewater by different reaction systems. (ozone concentration: 5 ± 1 mg/L, initial COD concentration:155 ± 15 mg/L, gas flow: 1 L/min, pH: 7, reflux ratio: 100:1, treated wastewater volume: 2 L).

Literature on the catalytic ozonation of actual wastewater by activated metals loaded with alumina was compared. As shown in Table 1, although the removal efficiency of organic pollutants in actual wastewater is different owing to some factors, such as water quality difference, catalyst difference and catalytic ozonation reactor difference, aluminium oxide loaded with metal elements can effectively improve the removal efficiency of organic pollutants and has been widely studied. In addition, Table 2 shows a literature comparison of other advanced oxidation processes for coking wastewater treatment. Different advanced oxidation processes have been widely used for coking wastewater treatment. The removal efficiencies of coking wastewater differed, which may be attributed to different initial pollutant concentrations, different operating parameters and conditions, and different treatment water volume of the coking wastewater. For the actual treatment of coking wastewater, the treatment process should be reasonably selected according to the specific water quality of coking wastewater. In this study, the catalytic ozonation process using Fe-Mn-Cu-Ce/Al₂O₃ catalyst could effectively remove organic pollutants from coking wastewater.

Table 1 Literature comparison of catalytic ozonation of practical wastewater using alumina supported active metals as catalyst.

Type of catalyst	S_BET（m²/g）	Type of wastewater	Reaction conditions	Removal efficiency	Reference
Mn-Fe-Mg-Ce/Al₂O₃	225	petroleum refinery wastewater	[O₃] = 5 mg/min; t = 15 min;[TOC] = 35.24 mg/L; GF = 0.5 L/min; [Catalyst] = 0.5 g; TWV = 0.1L;	[TOC]= 45.6 %	(Chen et al., 2017)
Mn-Fe-Cu/ Al₂O₃	253	petroleum refinery wastewater	[O₃] = 36.5 mg/min;t = 60 min; [COD] = 2825 mg/L; [Catalyst] = 15 g; TWV = 3L;	[COD]= 67.1 %	(Chen et al., 2015)
Mn-Cu/ Al₂O₃	81.69	tannery wastewater	[O₃] = 5 mg/min;t = 60 min; [COD] = 135–150 mg/L; [Catalyst] = 2 g; TWV = 1L;	[COD]= 86.4 %	(Huang et al., 2016)
Mn-Cu-Ce/ Al₂O₃	195.97	coal chemical wastewater	[O₃] = 10 mg/L;GF = 0.5 L/min; t = 120 min;[TOC] = 168 mg/L; [Catalyst] = 1 g;TWV = 0.5L;	[TOC]= 70.2 %	(Zhao et al., 2021)
Fe-Bi/ Al₂O₃	264.43	Wastewater from chemical industry park	[O₃] = 0.2 L/min; t = 60 min; [COD] = 206 mg/L; the inner diameter of the reactor = 4 cm; the column height of the reactor = 32 cm; [Catalyst filling ratio] = 10 %; TWV = 0.24L;	[COD]= 83.9 %	(Guo et al., 2022)
Fe-Cu-Ce-Mn/ Al₂O₃	—	Chemical wastewater	[O₃] = 40 mg/L; t = 40 min; [COD] = 69.63–103.26 mg/L; the inner diameter of the reactor = 6 cm, the height of the reactor = 55 cm, [Catalyst filling ratio] = 70 %; TWV = 0.24L;	[COD]= 36 %	(Ma et al., 2022)
Ca-C/ Al₂O₃	151.8	high salt organic wastewater	[O₃] = 12 mg/L;t = 40 min; [COD] = 100 ∼ 126 mg/L; [Catalyst] = 20 g;TWV = 0.05L;	[COD]= 64.4 %	(Chen et al., 2022)
Mn-Ce / Al₂O₃	195	coking wastewater	[O₃] = 80 mg/(L·h); t = 90 min; GF = 0.48 m³/h; [COD] = 150 mg/L; [Catalyst] = 72 kg;	[COD]= 45.6 %	(He et al., 2020)
Mn-Fe-Ce/ Al₂O₃	159.97	dairy farming wastewater	[O₃] = 12.5 mg/L; t = 20 min; GF = 0.6 L/min;[COD] = 460 mg/L; [Catalyst] = 15 g;TWV = 3.6L;	[COD]= 48.9 %	(Li et al., 2020)

S_BET, [O₃], [catalyst], GF, t, TWV, [COD]、[TOC] respectively represent BET surface area, O₃ dose, catalyst dosage, gas flow, reaction time, treated water volume, initial COD concentration of wastewater and initial total organic carbon concentration.

Table 2 Literature comparison of some advanced oxidation technologies for coking wastewater treatment.

Type of advanced oxidation process	Type of wastewater	Initial COD concentration (mg/L)	COD removal efficiency	Reference
electrochemical process	bio-treated coking wastewater	230 ± 20	83.05 %	(He et al., 2022)
photocatalysis-Fenton process	Coking wastewater	145.62	63.60 %	(An et al., 2023)
electro-Fenton process	coking wastewater from a conditioning pond	1730	87.50 %	(Hu et al., 2022)
Peroxymonosulfate / chloridion oxidation process	Coking wastewater concentrate	303.3	47.94 %	(Wang and Wang 2020)
Peroxymonosulfate / chloridion oxidation process	Coking wastewater concentrate	247.6	42.41 %	(Wang and Wang 2020)
Fenton-like process	Coking wastewater from the system before anaerobic treatment	7900	71 %	(Qin et al., 2019)
Fenton-like process	Coking wastewater from the system after aerobic process	263	89 %	(Qin et al., 2019)
photocatalysis process	Coking wastewater	2030	89.80 %	(Gao et al., 2011)
Wet oxidation process	real coke wastewater containing high thiocyanate concentration	1408	51 %	(Oulego et al., 2014)
Fenton oxidation process	coking wastewater after ammonia stripping	7500–8400	44–50 %	(Chu et al., 2012)

3.2

3.2 Characterization of catalysts

The physical and chemical properties of the Fe-Mn-Cu-Ce/Al₂O₃ catalysts were analysed using XRD, XRF, XPS, SEM, and BET nitrogen adsorption–desorption isotherms. Fig. 3 shows the XRD patterns of the support materials for catalysts (SCA) and catalysts (CA). As seen, the diffraction peaks of the catalyst and its support are consistent with those of quartz (PDF:46–1045) and aluminium (PDF:04–0880). The diffraction peaks at 2θ values of 20.9°, 26.6°, 36.5°, 39.5°, 42.5°, 45.8°, 50.1°, 60°, and 67.7° corresponded to the (1 0 0), (1 0 1), (1 1 0), (1 0 2), (2 0 0), (2 0 1), (1 1 2), (2 1 1) and (2 1 2) planes of quartz, respectively. The diffraction peaks at 2θ values of 37.4°, 39.7°, 45.8°, and 67.3° are attributed to the (3 1 1), (2 2 2), (4 0 0), and (4 4 1) planes of aluminium oxide, respectively. These results indicate that the crystalline phase of the catalyst was not affected by the preparation process (Chen et al., 2014, Tang et al., 2016). It should be noted that the diffraction peaks of other metal oxides were not clearly identified in the XRD pattern; possibly due to the low content of other metal oxides.

Table 3 summarises the elemental compositions of CA and SCA were analysed using XRF spectroscopy. The contents of Al₂O₃ and SiO₂ accounted for ∼ 98 % of the SCA, while Fe₂O₃, MnO, CuO, and CeO₂ were not identified. Besides the main Al₂O₃ and SiO₂ in the CA, the percentages of Fe₂O₃, MnO, CuO, and CeO₂ were 1.1 %, 0.29 %, 0.177 %, and 0.147 %, respectively. These findings suggest that that Fe, Mn, Cu, and Ce were efficiently loaded onto the carrier.

Table 3 Results of XRF analysis of SCA and CA.

Parameter (wt%)	CA	SCA
Al₂O₃	89.67	91.3563
SiO₂	7.39	6.5891
Fe₂O₃	1.1	Not detected
Na₂O	0.582	0.7165
MnO	0.29	Not detected
CaO	0.193	0.4168
CuO	0.177	Not detected
K₂O	0.171	0.1932
CeO₂	0.147	Not detected
MgO	0.13	0.1151
SO₃	0.0249	0.3452

Fig. 4 shows the chemical forms of the surface elements in CA and SCA. As seen, the full XPS spectrum confirms that that CA contained Fe (3.54 %), Mn (1.7 %), Cu (1.33 %), and Ce (0.83 %). However, these elements were not detected in SCA, thereby corroborating that the preparation of the catalyst was successful.

Fig. 5 illustrates the scanning electron microscope-based analysis of the surface morphological characteristics of CA and SCA. The analysis demonstrated that the surface morphology of SCA was relatively smooth, while that of CA was relatively rough. This contrast was potentially driven by the uniform loading of some metal oxides on the surface of the catalyst support, which strengthened the catalytic capacity of the catalyst (Song et al., 2022). EDS analysis in Fig. 6 further demonstrated that the elemental composition of the materials on the CA contained mainly Al, O, Si, Fe, Mn, Cu, and Ce, which also indicated that the catalyst was efficiently prepared.

SEM images of CA at 100,000× (a) and 10,000 × magnification (b) and SEM images of SCA at 100,000× (c) and 10,000× (d) magnification.

As shown in Fig. 7a, a typical H3 hysteresis loop as well as a type IV adsorption branch indicated that CA and SCA have mesoporous characteristic structures (Sing et al., 1985, Li et al., 2018, Yang et al., 2022 ). Moreover, the presence of hysteresis loops indicates that the catalyst synthesis process did not considerably destroy the carrier structure (Zhu et al., 2022). Fig. 7(b) shows the BJH pore size distribution plots of SCA and CA. The BET surface area and pore volume of CA and SCA are shown in Table 4. Relative to SCA, the specific surface area, pore volume and pore diameter of CA decreased from 242.54 m²/g, 0.3764 cm³/g, and 6.75 nm to 216.91 m²/g, 0.3111 cm³/g, and 6.11 nm, respectively. This difference was potentially driven by the blockage of some mesopores during the preparation of CA (Hou et al., 2020). The mesoporous structure of the catalyst will help improve the catalytic performance of the reaction system.

Nitrogen adsorption and desorption isotherms (a) and BJH pore size distribution plots (b) of CA and SCA.

Table 4 Results of BET analysis of SCA and CA.

Parameter	CA	SCA
BET Surface Area (m²/g)	216.91	242.54
Pore Volume (cm³/g)	0.3111	0.3764
Average Pore Size (nm)	6.11	6.75

3.3

3.3 Parameter optimization of catalytic ozonation process

3.3.1

3.3.1 Effect of catalyst dosage

Fig. 8 displays the effect of the catalyst dosage (0–625 g/L) on the removal of organic pollutants from the coking wastewater. After the coking raw water was treated with catalytic ozonation for 1 h, the removal effect of different catalyst dosages on the COD of coking wastewater was found to be as follows: 625 g/L (52.67 %) > 500 g/L (51.03 %) > 375 g/L (40.28 %) > 250 g/L (29.63 %) > 125 g/L (24.62 %) > 0 g/L (21.54 %). Overall, the degradation efficiency gradually increased with the increasing catalyst dosage. This could be due to the increase in catalyst dosage, which facilitated the increase in radical concentration, thereby inducing the efficient degradation of organic pollutants (Huang et al., 2021). However, when the catalyst dosage was excessively high, the degradation efficiency of the wastewater increased slowly, possibly due to the quenching reaction (Jothinathan et al., 2021). It is also reasonable to suggest that a change in the catalyst filling height may have indirectly affected the mass transfer effect in the reactor, thereby weakening the degradation efficiency. Due to this, the catalyst dosage was set to 500 g/L in the laboratory-scale experiment considering the process cost and degradation efficiency.

Effect of catalyst dosage on the degradation of coking wastewater. (ozone concentration: 5 ± 1 mg/L, initial COD concentration: 155 ± 15 mg/L, gas flow: 1 L/min, pH: 7, reflux ratio: 100:1, treated wastewater volume: 2 L).

3.3.2

3.3.2 Effect of pH

Fig. 9 illustrates the effect of different pH values on the degradation efficiency of the coking wastewater. The degradation efficiency of the coking wastewater after the 1 h treatment can be ranked depending on pH values as follows: pH = 7.00 (49.54 %) > pH = 9.00 (48.16 %) > pH = 11.00 (47.76 %) > pH = 5.00 (45.11 %) > pH = 3.00 (43.38 %). The results indicate that COD removal efficiency was stronger when the pH was neutral and weakly alkaline, possibly due to the following phenomenon: the radicals were more likely to be produced in the catalytic ozone oxidation system under neutral and alkaline conditions (Mohsin and Mohammed 2021, Zhao et al., 2021). The pH point of zero charge (pHpzc) of the catalyst was found to be ∼ 7.82, as shown in Fig. 9. Moreover, the surface hydroxyl of the catalyst exhibited a hydrogenated surface (pH < 7.82) and hydroxylated surface (pH > 7.82) depending on the pH. When the pH was 7, the best degradation effect of organic pollution was identified. Most likely, since its pH was close to pHpzc, the surface hydroxyl group was not greatly affected. Thus, it can be used as an active site to accelerate ozone decomposition.

Effect of pH on the degradation of coking wastewater. (ozone concentration: 5 ± 1 mg/L, initial COD concentration: 155 ± 15 mg/L, gas flow: 1 L/min, catalyst dosage: 500 g/L, reflux ratio: 100:1, treated wastewater volume: 2 L).

3.3.3

3.3.3 Effect of reflux ratio

In general, an additional circulation pump can indirectly change the mass transfer effect of water, gas, and solids in the system, thereby affecting the degradation efficiency of organic pollutants (Ma et al., 2018). Due to this, the effects of different reflux ratios on the removal efficiency were compared. Fig. 10 shows that the degradation efficiencies at the different reflux ratios were in the following order: reflux ratio of 100:1 (51.26 %) > reflux ratio of 75:1 (47.36 %) > reflux ratio of 50:1 (39.54 %) > reflux ratio of 25:1 (32.87 %) > reflux ratio of 0 (27.13 %). As the reflux ratio increased, the removal efficiency of organic pollutants from wastewater increased significantly; possibly due to the enhanced mass transfer effect (Zhang et al., 2022). The highest degradation efficiency of organic pollutants in coking wastewater was identified when the reflux ratio was 100:1 in the laboratory-scale experiment.

Effect of reflux ratio on wastewater degradation. (ozone concentration: 5 ± 1 mg/L, initial COD concentration: 155 ± 15 mg/L, gas flow: 1 L/min, pH: 7, catalyst dosage: 500 g/L, treated wastewater volume: 2 L).

3.4

3.4 Catalytic mechanism

3.4.1

3.4.1 Ozone utilization rate and active site

It is conducive to ameliorate the treatment efficiency of organic pollutants to enhance the utilisation rate of ozone (Sun et al., 2020). Therefore, the utilisation of ozonation and catalytic ozonation systems in the degradation of phenol were examined. Fig. 11 (a) shows that the ozone utilisation rate gradually decreased with increasing reaction time in both ozonation and catalytic ozonation systems. However, the ozone utilisation rate in the catalytic ozonation system was much higher than that in the ozonation system. When the reaction time was 60 min, the ozone utilisation rate of the catalytic ozone system was 38.9 % higher than that in the ozonation system. The ozone utilisation rate in the catalytic ozonation system was 1.1–1.8 times that in the ozonation system, thus indicating that the catalyst was conducive to the rapid decomposition and efficient utilisation of ozone, and bolstered the degradation efficiency of organic pollutants.

(a) Ozone utilization rate of single ozone system and catalytic ozonation system. (b) Fourier transform infrared spectroscopy of CA and SCA(b). (c) Effect of NaH2PO4 on COD removal with Fe-Mn-Cu-Ce/Al2O3 catalyst. (ozone concentration: 5 ± 1 mg/L, initial phenol concentration: 50 mg/L, gas flow: 1 L/min, reflux ratio: 100:1, treated wastewater volume: 2 L).

Lewis acid sites on the catalyst surface form surface hydroxyl groups during the catalytic ozonation process, which may serve as active sites in the catalytic ozonation process (Nawrocki and Kasprzyk-Hordern 2010). Fig. 11 (b) shows how Fourier transform–infrared spectroscopy was used to analyse the functional groups on the surface of the catalyst and its support. The response peak near 3,471.73 cm⁻¹ was identified, which may have been driven by the –OH stretching of water adsorbed on the catalyst surface. Furthermore the response peak near 1,634.79 cm⁻¹ have been caused by the bending vibration of the O—H bond of free water or adsorbed water (Bokhimi et al., 2001, Peng et al., 2018). The response peak near 1,384.28 cm⁻¹ may be the characteristic peak formed by the interaction between Lewis acid sites and ozone. The response peak near 1,079.64 cm⁻¹ may have been triggered by the bending vibration in the C-OH bond plane (Bulla et al., 2004, Ke et al., 2020). The broad response spectrum peak located near 500 ∼ 700 cm⁻¹ may have been caused by the vibration of various metal oxides (Huong et al., 2016, Du et al., 2019, Shahmahdi et al., 2020, Ederer et al., 2021 ). Notably, the response peak of the catalyst near 1,384.28 cm⁻¹ was significantly higher than that of the carrier, thereby indicating that the catalyst potentially had more Lewis acid sites due to the carrier of Fe, Mn, Cu, and Ce.

In general, phosphate can deprotonate the surface hydroxyl groups of the catalyst and affect its catalytic efficiency (Li et al., 2019). The effect of phosphate addition on the degradation efficiency of phenol was compared to elucidate the influence of Lewis acid sites on the catalyst surface. Fig. 11 (c) demonstrates that the addition of phosphate significantly hindered the degradation efficiency of organic pollutants, thereby suggesting that the catalytic performance of the catalyst was affected by the Lewis acid sites and surface hydroxyl groups. Moreover, the Lewis acid sites of the catalyst may have been catalytically active sites.

In order to further study the role of the four active metals in the catalytic ozonation process, XPS was used to gain further insights into the surface compositions of Fe-Mn-Cu-Ce/Al₂O₃ before and after the catalytic ozonation reaction. Fe2p, Mn2p, Cu2p, Ce3d, and O1s XPS spectra of these catalysts were illustrated in Fig. 12 and Figure S2. The O1s spectrum (Figure S2) could be decomposed into two components at binding energy of 529.8 and 530.9 eV, which might be respectively attributable to lattice oxygen and adsorbed oxygen (Yang et al., 2022). Adsorbed oxygen as surface reactive oxygen species, which can easily capture free electrons and act as active sites for adsorption and decomposition of ozone into ·OH, thus promoting the degradation of organic pollutants (Long et al., 2019). The Fe 2p XPS spectra were exhibited in Fig. 12 (a). The binding energies of Fe 2p_1/2 and Fe 2p_3/2 were located at 723.9 and 710.6 eV, respectively. The peaks of 709.7(2p3/2) and 711.8(2p3/2) eV were considered to Fe (II) and Fe (III), respectively, indicating that Fe mainly existed in the form of Fe (II) and Fe (III) (Yang et al., 2022). The Mn 2p XPS spectra were exhibited in Fig. 12 (b). The binding energies of Mn 2p_1/2 and Mn 2p_3/2 were located at 653.3 and 642 eV, respectively. Then for Mn 2p_3/2, the peaks of 641.8 and 643 eV were considered to Mn (III) and Mn (IV), respectively, indicating that Mn mainly existed in the form of Mn (III) and Mn (IV) (Zhang et al., 2021). As shown in Fig. 12 (c), the binding energies of Cu 2p_1/2 and Cu 2p_3/2 were located at 953.6 and 933.3 eV, respectively. The Cu in the catalyst was present as Cu (II) and Cu (0)/ Cu (I), with peaks at 933.2 eV (2p3/2) and 935.3 eV (2p3/2) in the Cu 2p spectrum corresponding to Cu (0)/ Cu(I) and Cu (II), respectively (Wang et al., 2021). As shown in Fig. 12 (d), the Ce 3d XPS spectrum of Fe-Mn-Cu-Ce/Al₂O₃ was deconvoluted into 5 pairs of doublets, where V and U represented the 3d_5/2 and 3d_3/2 spin–orbit splits of Ce, respectively. The peaks U (901.2 eV), U″ (907.2 eV), U‴ (917.1 eV) and V (882.8 eV), V″ (889.6 eV), V‴ (898.2 eV) were attributed to Ce (IV), while the peaks V⁰ (880.7 eV), V′ (886.1 eV) and U⁰ (899.6 eV), U′ (904 eV) were attributed to Ce (III), indicating that Ce mainly existed in the form of Ce (III) and Ce (IV) (Zhang et al., 2022). Four metals with different valence states were conducive to the formation of reactive oxygen, maintain the conservation of total charge, and thus improve the degradation efficiency of organic pollutants (Shao et al., 2022).

XPS spectra of (a) Fe 2p, (b) Mn 2p, (c) Cu 2p, and (d) Ce 3d of Fe-Mn-Cu-Ce/Al2O3.

The element species composition of the catalyst was summarized in Table S1. After catalytic ozonation, the Fe (II) content was decreased from 64.2 % to 59.55 %; the Cu (0)/Cu (I) content was decreased from 73.34 % to 69.48 %; the Mn (III) content was decreased from 65.58 % to 62.23 %; the Ce (III) content was increased from 38.35 % to 40.84 %; the Fe (III) content was increased from 35.79 % to 40.45 %; the Cu (II) content was increased from 26.67 % to 30.52 %; the Mn (IV) content was increased from 34.41 % to 37.77 %; and the Ce (IV) content was decreased from 61.65 % to 59.16 %. Therefore, iron species, manganese species, and copper species were oxidized in the reaction process, and cerium species was reduced in the reaction process. In other words, the Fe (II)-Fe (III), Mn (III)- Mn (IV), Cu (0)/Cu (I)- Cu (II) and Ce (III)- Ce (IV) redox centers participated in the catalytic reaction process. In addition, the adsorbed oxygen content was decreased from 86.28 % to 71.38 % and the lattice oxygen content was increased from 13.72 % to 28.62 %, which may indicate that besides adsorbed oxygen, lattice oxygen also participated in the catalytic reaction process. In conclusion, the couples of Fe (II)-Fe (III), Mn (III)- Mn (IV), Cu (0)/Cu (I)- Cu (II) and Ce (III)- Ce (IV) facilitated the dissociation of ozone into reactive oxygen species, thus improving the catalytic activity of Fe-Mn-Cu-Ce/Al₂O₃ (Guo et al., 2019).

3.4.2

3.4.2 Detection of reactive oxygen species

To further evaluate the presence of reactive oxygen in the catalytic ozonation system, the reactive oxygen was detected using the EPR method (Li et al., 2022, Tu et al., 2022). Fig. 13 (a) shows that although the characteristic spectrum of superoxide radicals was detected in both the single and catalytic ozonation systems, the response value of the characteristic peak of superoxide radicals in the catalytic oxidation system was significantly higher than that in the separate ozonation system. As shown in Fig. 13 (b), singlet oxygen existed in the single ozonation system and catalytic ozonation system. Moreover, the characteristic peak response value of singlet oxygen in the catalytic oxidation system was significantly higher than that in the single ozonation system, which indicated that a high concentration of superoxide radicals and singlet oxygen strengthened the degradation efficiency of organic pollutants. Moreover, Fig. 13 (c) shows that the hydroxyl radical response values in the catalytic ozonation system were significantly higher than those in the single ozone oxidation system, compared with the single ozonation system. These findings indicate that reactive oxygen played a key role in the degradation of organic compounds in the catalytic ozonation system.

EPR method analysis of (a) superoxide radicals, (b) singlet oxygen, and (c) hydroxyl radicals. (d) Effect of TBA on hydroxyl radicals. (ozone concentration: 5 ± 1 mg/L, initial COD concentration: 155 ± 15 mg/L, gas flow: 1 L/min, pH: 7, reflux ratio: 100:1, TBA concentration: 38.75 mg/L, treated wastewater volume: 2 L).

To evaluate the presence of hydroxyl radicals in the catalytic ozonation system, tert-butanol (TBA) was further selected as a scavenger of hydroxyl radicals due to its high reaction rate constant with hydroxyl radicals and low reaction rate constant with ozone (Sun et al., 2020, Jothinathan et al., 2022). Fig. 13 (d) displays the effect of the addition on the catalytic ozonation and ozone oxidation systems. As seen, when TBA was added, the degradation efficiencies of the catalytic ozonation system and the single ozone oxidation system were nearly equal. This quasi-equality was likely driven by the reduction of the hydroxyl radical concentration in the catalytic ozonation system, caused by tert-butanol. Overall, these results corroborate that the hydroxyl radicals were generated in the catalytic ozonation system.

To explore the effect of active oxygen on the degradation of organic pollutants, three quenching agents (TBA for ·OH, pBQ for ·O₂^–, and FFA for ¹O₂) were used to study the effect of active oxygen on the removal rate of phenol (Figure S3) (Guo et al., 2021, Guo et al., 2022). As shown in Figure S3, in the ozonation system, the addition of TBA, pBQ, and FFA reduced the phenol removal rate by 15.53, 19.57, and 20.04 %, respectively, indicating that hydroxyl radical, superoxide radical, and singlet oxygen also existed in the ozonation system. Compared with the ozonation system, the addition of TBA, pBQ, and FFA in the catalytic ozonation system greatly reduced the phenol removal rate by 39.6, 55.23, and 55.66 %, respectively. This result showed that in the catalytic ozonation system, organic pollutants were mainly degraded by free radicals (·OH, ·O₂^–, and ¹O₂), which was consistent with the results of EPR. Notably, the introduction of quenching agents may lead to changes in the degradation mechanism of organic substances in the catalytic ozonation system, and the quantitative analysis of the removal efficiency of organic pollutants by active oxygen needs to be studied further (Guo et al., 2022).

3.4.3

3.4.3 Possible reaction mechanism

Fig. 14 illustrates a possible reaction mechanism for the degradation of organic pollutants by catalytic ozonation using Fe-Mn-Cu-Ce/Al₂O₃. Given the adsorption of the catalyst, some of the organic pollutants in the wastewater were identified at the surface of the catalyst. As a strong oxidant, ozone can directly degrade the organic pollutants in wastewater into intermediates. Moreover, the ozonation process itself can also form a low concentration of reactive oxygen species, thereby indirectly degrading organic pollutants in wastewater (Li et al., 2018, Xu et al., 2019). During the catalytic ozonation, ozone can react with the active sites on the surface of the catalyst to generate a high concentration of reactive oxygen species, thus indirectly degrading organic pollutants in wastewater. After the degradation of organic pollutants, the intermediates can be further mineralised into carbon dioxide and water. It should be noted that the presence of quencher can generally weaken the efficiency of reactive oxygen species in the treatment of organic pollutants.

Reaction mechanism of catalytic ozonation using Fe-Mn-Cu-Ce/Al2O3.

3.5

3.5 Pilot test of catalytic ozonation degradation of coking wastewater

Compared with the laboratory scale catalytic ozonation experiment, the pilot scale catalytic ozonation experiment had significant differences in initial pollutant concentration, treatment water volume, and reactor. According to the results of the laboratory scale catalytic ozonation parameter optimisation experiment, we found that increasing the reflux ratio and catalyst dosage can improve the removal efficiency of COD in coking wastewater. In addition, when the initial pH value of coking wastewater is close to the equal point potential of the wastewater, it is beneficial to improve the removal efficiency of COD in coking wastewater. Therefore, in consideration of the above factors and cost, during the pilot scale test of catalytic ozonation, no acid and alkali agents were used to adjust the initial pH value of coking wastewater. In addition, to save costs, the catalyst dosage and reflux ratio were set at 250 g/L and 50:1, respectively, during the pilot scale catalytic ozonation experiment. In the pilot scale catalytic ozonation experiment, the effects of initial pollutant concentration, ozone concentration, and gas flow rate on the COD removal efficiency of coking wastewater were studied.

3.5.1

3.5.1 Parameter optimization of catalytic ozonation process

3.5.1.1

3.5.1.1 Effect of initial pollutant concentration

During the pilot period, the effluent COD concentration exhibited significant fluctuations. Due to this, the effects of wastewater with different initial pollutant concentrations on the catalytic ozonation process were elucidated (see Fig. 15). As the initial COD concentration of the coking wastewater increased, the wastewater degradation efficiency was also gradually strengthened. This pattern was likely driven by the poor effluent quality of the biochemical process, and because many easily degradable organic pollutants entered the catalytic ozonation stage (Sheydaei et al., 2022). However, when the initial COD concentration was excessively high (COD > 200 mg/L), the COD concentration was difficult to meet the discharge standards (COD < 80 mg/L) after 3 h. The organic pollutants in wastewater degrade rapidly in the early stage and exceptionally slowly at the later stage. This pattern was possibly triggered by the decomposition of easily degradable large-molecule organic pollutants into difficult-to-degrade small-molecule organic pollutants as the reaction time increased. Overall, this phenomenon decelerated the degradation rate of organic pollutants in wastewater, which implied that it is very difficult to meet the standard discharge in a short time. When the initial COD concentration of the coking wastewater was < 200 mg/L, the wastewater steadily met the wastewater discharge standard after 2 h of catalytic ozonation degradation; possibly due to the control of the total organic matter content during the catalytic ozonation process (Petre et al., 2015).

Effect of initial COD concentration on degradation efficiency. (ozone concentration: 30 ± 1 mg/L, reflux ratio: 50:1, gas flow: 1 L/min, catalyst dosage: 250 g/L, pH: 7.50 ± 1.40, treated wastewater volume: 300 L).

To elucidate the effect of the initial pollutant concentration on the degradation efficiency in detail, catalytic ozonation experiments were conducted for 5 h with coking wastewater (see Figure S4). As the reaction time increased, the concentration of COD in the wastewater gradually decreased. The degradation effect of the wastewater in the first 2 h was significantly better than that in the last 3 h. When the concentration of influent COD was ∼ 300 mg/L, the concentration of COD reached ∼ 90 mg/L after 5 h of degradation. Thus, the wastewater discharge standard has not been reached. When the influent COD concentration ∼ 165 mg/L, the concentration of COD reached ∼ 60 mg/L after 5 h of degradation. Therefore, it is crucial to reduce the initial COD concentration in coking wastewater.

3.5.1.2

3.5.1.2 Effect of ozone concentration

As the ozone concentration plays a vital role in the effectiveness of wastewater degradation, the ozone concentration was examined in this study (Chen et al., 2021). Fig. 16 shows that when the ozone concentration was 30 mg/L, the wastewater met the wastewater discharge standards after 2 h of the degradation. As ozone is a strong oxidant, by increasing its dosage, one can strengthen the wastewater degradation efficiency (Sathya et al., 2019, Wang et al., 2020). However, the increase in ozone concentration did not significantly increase the degradation efficiency of organic pollutants. On this basis, an ozone concentration of 30 mg/L was selected for subsequent experiments on coking wastewater.

Effect of ozone concentration on coking wastewater. (reflux ratio: 50:1, gas flow: 1 L/min, catalyst dosage: 250 g/L, pH: 7.50 ± 1.40, treated wastewater volume: 300 L).

3.5.1.3

3.5.1.3 Effect of gas flow

Fig. 17 shows the effect of different gas flow rates (0.25 L/min, 0.5 L/min, 0.75 L/min, and 1 L/min) on the degradation efficiency of the coking wastewater. The degradation efficiency was enhanced with an increase in the gas flow rate. This phenomenon is potentially attributed to the underlying increase in the oxide concentration with increasing gas flow rate (Ranjbar Vakilabadi et al., 2017, Shang et al., 2021). Note that only when the gas flow rate was 1 L/min, the COD of the wastewater reached the wastewater discharge standard after 2 h of the degradation. To this end, a gas flow rate of 1 L/min was selected for ensuring that the coking wastewater met the standard discharge.

Effect of gas flow on coking wastewater. (ozone concentration: 30 ± 1 mg/L, reflux ratio: 50:1, catalyst dosage: 250 g/L, pH: 7.50 ± 1.40, treated wastewater volume: 300 L).

3.5.2

3.5.2 Reusability of the catalyst

As the reusability of the catalyst is an important factor for the stable operation of catalytic ozonation, the long-term treatment performance of the process was elucidated (Fig. 18) (Nakhate et al., 2019). When the COD concentration of the coking raw water was < 200 mg/L, the effluent met the coking wastewater discharge standard steadily for 32 days. The degradation efficiency of the wastewater was estimated to be ∼ 60 %, thereby suggesting that the catalyst could maintain high catalytic activity and stability during continuous operation.

Long-term performance of catalytic ozonation for coking wastewater under pilot test. (ozone concentration: 30 ± 1 mg/L, reflux ratio: 50:1, gas flow: 1 L/min, catalyst dosage: 250 g/L, pH: 7.50 ± 1.40, treated wastewater volume: 300 L).

3.5.3

3.5.3 Operation cost of catalytic ozonation in the pilot-scale study

As catalytic ozonation technology is relatively mature for the degradation of organic pollutants, this study did not evaluate the costs of fixed expenditures, such as infrastructure, labour, equipment, and catalyst replacement cost. Rather, this study further focused on the evaluation of the operating costs of catalytic ozonation degradation of organic pollutants. The operating cost of this process is primarily the electricity charge for O₃ production. When the ozone concentration was 30 mg/L, the gas flow rate was 1 L/min, reaction time was 120 min, the wastewater treatment volume was 300 L, and operating cost was ∼ 0.032 $/m³, thereby indicating acceptable conditions for engineering applications.

3.6

3.6 Kinetic analysis

The kinetics of wastewater degradation provide reliable guidelines for efficient degradation of coking wastewater (Mathon et al., 2021). Thus, it is necessary to elucidate the kinetics of wastewater degradation. Pseudo-first-order and pseudo-second-order reaction kinetics were performed to degrade COD in coking wastewater under different parameters. The kinetic order of the organic pollutants in the coking wastewater was determined by analysing the R² value. Tables S2–S7 summarise organic the pseudo-first-order and pseudo-second-order degradation kinetics of organic pollutants in the coking wastewater under different parameters. As seen, the R² fitting effect of the pseudo-second-order reaction kinetics was significantly better than that of the pseudo-first-order reaction kinetics. This result indicates that, in this study, pseudo-second-order reaction kinetics were potentially more accurate for the degradation process of organic pollutants in coking wastewater. In general, coking wastewater contains abundant organic compounds that react with ozone according to pseudo-second-order kinetics, such as aromatic compounds, heterocyclic compounds, and nitrogen-containing organic pollutants, which potentially explains why the COD degradation of coking wastewater followed pseudo-second-order kinetics (Lim et al., 2022).

3.7

3.7 Removal behavior of organic pollutants

3.7.1

3.7.1 3D-EEM analysis

As the 3D-EEM method can identify pollutants in coking wastewater according to different fluorescence-corresponding areas, many scholars have previously used it as a good indicator for water quality analysis because it is rapid, accurate, and simple to apply (Fu et al., 2019, He et al., 2021). The three-dimensional fluorescence spectrum can be divided into five main fluorescence response regions. Fig. 19(a) shows that the coking raw wastewater had fluorescence response values in all five primary divisions, indicating that the wastewater contained organic matter, such as aromatic proteins, fulvic acid organics, humic acid-like compounds, and soluble microbial metabolites. Notably, the wastewater exhibited larger fluorescence response values in the second and fourth regions, thereby pointing out relatively high concentrations of aromatic protein type II substances and soluble row microbial metabolites in the coking wastewater. Moreover, Fig. 19 (b) shows that the fluorescence response values of each region were significantly reduced, thus indicating that the concentration of organic pollutants in the wastewater was efficiently degraded. However, although the fluorescence response values were markedly reduced, some fluorescence response peaks were identified in the second and fourth regions of the spectrum. We suggest that these pollutants contributed to the residual COD concentration in the effluent.

3D-EEM spectrum of coking wastewater before (a) and after (b) treatment under pilot-scale experiment.

3.7.2

3.7.2 GC–MS analysis

To investigate the changes in wastewater quality before and after the treatment in detail, the wastewater was analysed using gas chromatography–mass spectrometry (GC–MS) (Jayapal et al., 2022, Liu et al., 2022, Yang et al., 2022 ). According to the GC–MS profiles of the influent and effluent, the total number of pollutant species decreased from 221 to 174 after the treatment with ozone catalytic ozonation, as indicated by Figure S5. The molecular weight of the organic pollutants decreased after the treatment, due to the oxidation by ozone and reactive oxygen, indicating that most of the organic compounds were effectively degraded. However, numerous new peaks appeared in the GC–MS spectra of the effluent, being potentially driven by the incomplete mineralisation of organic pollutants.

3.7.3

3.7.3 Analysis in conventional water quality indexes

By analysing the changes in conventional water quality indicators, one can understand how to strengthen the degradation efficiency (Zubot et al., 2021). Table 5 shows that the turbidity and chromaticity values of the coking effluent significantly decreased, being potentially driven by the degradation of colloidal substances and organic pollutants containing chromogenic groups. The conductivity and TDS slightly increased. The pH value of the effluent remained unchanged, indicating that the catalytic ozonation process had little effect on the pH value. The zeta potential of the coking effluent tended to 0, thereby suggesting that the accessible flocculating substances were treated. Moreover, the DOC and UV₂₅₄ values of the coking effluent both decreased significantly. These results demonstrate that the organic pollutants in the wastewater were effectively degraded.

Table 5 Changes of conventional water quality indicators before and after coking wastewater treatment under pilot-scale experiment.

Water quality index name	Raw water	Coking wastewater effluent
Turbidity (NTU)	4.29 ± 1	1.76 ± 0.8
pH	7.50 ± 1.40	7.70 ± 1.20
Conductivity (μs/cm)	6330 ± 500	6880 ± 200
TDS (ppm)	3210 ± 300	3620 ± 150
DOC (mg/L)	35.11 ± 3	18.59 ± 2
UV₂₅₄ (cm⁻¹)	1.67 ± 0.25	0.46 ± 0.15
Zeta potential (mV)	−20 ± 5	−4 ± 1
Chromaticity (°)	216 ± 2	43.2 ± 3

3.8

3.8 Scope for future work

(1) In future research, different parameter optimisation methods, such as orthogonal method and response surface method, should be further used to explore the optimal conditions for the wastewater treatment process.

(2) Mathematical models, such as computational fluid dynamics, should be used in combination with practical engineering experience data to further study the impact of reactors on the degradation efficiency of organic pollutants, and the internal relationship between small reactors and pilot reactors should be established.

(3) Changes in the ozone utilisation rate by wastewater of different qualities should be further discussed, and the role of various active oxygen species in the catalytic ozonation system should be studied in detail by combining the quenching method, probe method, kinetic model analysis, and other analysis methods.

(4) The effects of other metal elements loaded on the catalyst and metal elements with different ratios loaded on the catalyst on the removal efficiency of organic pollutants in wastewater should be further studied.

4 Conclusions

Fe-Mn-Cu-Ce/Al₂O₃ catalysts were successfully prepared and applied for advanced treatment of coking wastewater in the catalytic ozonation system at the laboratory scale and pilot scale. The effects of catalyst dosage, pH, reflux ratio, ozone concentration, gas flow rate, and initial organic pollutant concentration on the removal of organic pollutants were studied and optimised. Under the optimal reaction conditions, the COD removal efficiency of bio-treated coking wastewater is approximately 50 %–60 %. The reaction mechanism experiment showed that the loading of active components (iron, manganese, copper, cerium) greatly increased the utilisation rate of ozone and promoted the degradation of organic pollutants. Lewis acid sites and reactive oxygen species (· OH, · O₂^–, and ¹O₂) may play a key role in the degradation of organic pollutants. In the 32-day pilot test, the catalyst showed good reusability and low operating cost (∼0.032 $/m³). The degradation kinetics experiment of COD in coking wastewater shows that the degradation process of COD conforms to the quasi second order kinetics. 3D-EEM and GC–MS showed that the organic pollutants in the treated coking wastewater were effectively degraded. In other words, the catalytic ozonation system using Fe-Mn-Cu-Ce/Al₂O₃ has a great application prospect in the advanced treatment of coking wastewater.

Acknowledgement

This study was supported by the National Water Pollution Control and Treatment Science and Technology Major Project of China (No. 2017ZX07402002). The funders of this study is Ministry of Ecology and Environment of the People's Republic of China.

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

References

AHA-AWWA-WEF, 1998. Standard Methods for the Examination of Water and Wastewater. 20th ed. American Public Health Association. Washington, DC
An W., Wang H., Yang T., . Enriched photocatalysis-Fenton synergistic degradation of organic pollutants and coking wastewater via surface oxygen vacancies over Fe-BiOBr composites. Chem. Eng. J.. 2023;451
[CrossRef] [Google Scholar]
Bokhimi X., Toledo J.A., Navarrete J., . Thermal evolution in air and argon of nanocrystalline MoS₂ synthesized under hydrothermal conditions. Int. J. Hydrogen Energy. 2001;26:1271-1277.
[CrossRef] [Google Scholar]
Bulla D.A.P., Li W.-T., Charles C., . Deposition and characterization of silica-based films by helicon-activated reactive evaporation applied to optical waveguide fabrication. Appl. Opt.. 2004;43:2978-2985.
[CrossRef] [Google Scholar]
Cai Q.Q., Wu M.Y., Li R., . Potential of combined advanced oxidation – biological process for cost-effective organic matters removal in reverse osmosis concentrate produced from industrial wastewater reclamation: screening of AOP pre-treatment technologies. Chem. Eng. J.. 2020;389
[CrossRef] [Google Scholar]
Chen C., Chen H., Guo X., . Advanced ozone treatment of heavy oil refining wastewater by activated carbon supported iron oxide. J. Ind. Eng. Chem.. 2014;20:2782-2791.
[CrossRef] [Google Scholar]
Chen C., Yoza B.A., Wang Y., . Catalytic ozonation of petroleum refinery wastewater utilizing Mn-Fe-Cu/Al₂O₃ catalyst. Environ Sci Pollut Res Int.. 2015;22:5552-5562.
[CrossRef] [Google Scholar]
Chen C., Li Y., Ma W., . Mn-Fe-Mg-Ce loaded Al₂O₃ catalyzed ozonation for mineralization of refractory organic chemicals in petroleum refinery wastewater. Sep. Purif. Technol.. 2017;183:1-10.
[CrossRef] [Google Scholar]
Chen J., Tu Y., Shao G., . Catalytic ozonation performance of calcium-loaded catalyst (Ca-C/Al₂O₃) for effective treatment of high salt organic wastewater. Sep. Purif. Technol.. 2022;301
[CrossRef] [Google Scholar]
Chen K.-C., Wang Y.-H., . The effects of Fe–Mn oxide and TiO₂/α-Al₂O₃ on the formation of disinfection by-products in catalytic ozonation. Chem. Eng. J.. 2014;253:84-92.
[CrossRef] [Google Scholar]
Chen X., Wang C., Jiang L., . Pilot-scale catalytic ozonation pretreatment for improving the biodegradability of fixed-bed coal gasification wastewater. Process Saf. Environ. Prot.. 2021;148:13-19.
[CrossRef] [Google Scholar]
China, M. o. E. P. o. t. P. s. R. o., 2012. Emission standard of pollutants for coking chemical industry (GB 16171-2012). General Administration of Quality Supervision, Inspection and Quarantine of the People’s Republic of China. URL: http://www.mee.gov.cn/ywgz/fgbz/bz/bzwb/shjbh/swrwpfbz/201207/t20120731_234146.shtml [In Chinese],
Chu L., Wang J., Dong J., . Treatment of coking wastewater by an advanced Fenton oxidation process using iron powder and hydrogen peroxide. Chemosphere. 2012;86:409-414.
[CrossRef] [Google Scholar]
Coha M., Farinelli G., Tiraferri A., . Advanced oxidation processes in the removal of organic substances from produced water: potential, configurations, and research needs. Chem. Eng. J.. 2021;414
[CrossRef] [Google Scholar]
Du X., Zhang Y., Si F., . Persulfate non-radical activation by nano-CuO for efficient removal of chlorinated organic compounds: reduced graphene oxide-assisted and CuO (0 0 1) facet-dependent. Chem. Eng. J.. 2019;356:178-189.
[CrossRef] [Google Scholar]
Ederer J., Janoš P., Šťastný M., . Nanocrystalline cerium oxide for catalytic degradation of paraoxon methyl: Influence of CeO₂ surface properties. J. Environ. Chem. Eng.. 2021;9
[CrossRef] [Google Scholar]
Faghihinezhad M., Baghdadi M., Shahin M.S., . Catalytic ozonation of real textile wastewater by magnetic oxidized g-C₃N₄ modified with Al₂O₃ nanoparticles as a novel catalyst. Sep. Purif. Technol.. 2022;283
[CrossRef] [Google Scholar]
Fu L., Wu C., Zhou Y., . Ozonation reactivity characteristics of dissolved organic matter in secondary petrochemical wastewater by single ozone, ozone/H₂O₂, and ozone/catalyst. Chemosphere. 2019;233:34-43.
[CrossRef] [Google Scholar]
Gao M.-J., Wang X.-D., Guo M., . Contrast on COD photo-degradation in coking wastewater catalyzed by TiO₂ and TiO₂–TiO₂ nanorod arrays. Catal. Today. 2011;174:79-87.
[CrossRef] [Google Scholar]
Gao Y.-Q., Zhou J.-Q., Rao Y.-Y., . Comparative study of degradation of ketoprofen and paracetamol by ultrasonic irradiation: mechanism, toxicity and DBP formation. Ultrason. Sonochem.. 2022;82:105906
[CrossRef] [Google Scholar]
Guo Q., Liu Y., Qi G., . Study of low temperature combustion performance for composite metal catalysts prepared via rotating packed bed. Energy. 2019;179:431-441.
[CrossRef] [Google Scholar]
Guo Y., Zhang Y., Yu G., . Revisiting the role of reactive oxygen species for pollutant abatement during catalytic ozonation: The probe approach versus the scavenger approach. Appl. Catal. B: Environ.. 2021;280
[CrossRef] [Google Scholar]
Guo Y., Long J., Huang J., . Can the commonly used quenching method really evaluate the role of reactive oxygen species in pollutant abatement during catalytic ozonation? Water Res.. 2022;215:118275
[CrossRef] [Google Scholar]
Guo L., Zhang M., Xie S., . Catalytic ozonation of high-salinity wastewater using salt-resistant catalyst Fe-Bi@γ-Al₂O₃. J. Water Process Eng.. 2022;49
[CrossRef] [Google Scholar]
He C., Wang J., Wang C., . Catalytic ozonation of bio-treated coking wastewater in continuous pilot- and full-scale system: efficiency, catalyst deactivation and in-situ regeneration. Water Res.. 2020;183
[CrossRef] [Google Scholar]
He C., He X., Li J., . The spectral characteristics of biochar-derived dissolved organic matter at different pyrolysis temperatures. J. Environ. Chem. Eng.. 2021;9
[CrossRef] [Google Scholar]
He L., Wang C., Chen X., . Preparation of Tin-Antimony anode modified with carbon nanotubes for electrochemical treatment of coking wastewater. Chemosphere. 2022;288:132362
[CrossRef] [Google Scholar]
Hou S., Jia S., Jia J., . Fe₃O₄ nanoparticles loading on cow dung based activated carbon as an efficient catalyst for catalytic microbubble ozonation of biologically pretreated coal gasification wastewater. J Environ Manage.. 2020;267:110615
[CrossRef] [Google Scholar]
Hu Y., Yu F., Bai Z., . Preparation of Fe-loaded needle coke particle electrodes and utilisation in three-dimensional electro-Fenton oxidation of coking wastewater. Chemosphere. 2022;308:136544
[CrossRef] [Google Scholar]
Huang Y., Liang M., Ma L., . Ozonation catalysed by ferrosilicon for the degradation of ibuprofen in water. Environ Pollut.. 2021;268:115722
[CrossRef] [Google Scholar]
Huang G., Pan F., Fan G., . Application of heterogeneous catalytic ozonation as a tertiary treatment of effluent of biologically treated tannery wastewater. J. Environ. Sci. Health Part a-Toxic/Hazard. Substances Environ. Eng.. 2016;51:626-633.
[CrossRef] [Google Scholar]
Huong P.T.L., Huy L.T., Phan V.N., . Application of graphene oxide-MnFe₂O₄ magnetic nanohybrids as magnetically separable adsorbent for highly efficient removal of arsenic from water. J. Electron. Mater.. 2016;45:2372-2380.
[CrossRef] [Google Scholar]
Jayapal M., Jagadeesan H., Krishnasamy V., . Demonstration of a plant-microbe integrated system for treatment of real-time textile industry wastewater. Environ. Pollut.. 2022;302:119009
[CrossRef] [Google Scholar]
Jothinathan L., Cai Q.Q., Ong S.L., . Organics removal in high strength petrochemical wastewater with combined microbubble-catalytic ozonation process. Chemosphere. 2021;263
[CrossRef] [Google Scholar]
Jothinathan L., Cai Q.Q., Ong S.L., . Fe-Mn doped powdered activated carbon pellet as ozone catalyst for cost-effective phenolic wastewater treatment: mechanism studies and phenol by-products elimination. J. Hazard. Mater.. 2022;424:127483
[CrossRef] [Google Scholar]
Ke P., Yue K., You Z., . Investigation on structure and luminescence properties of Yb3+-doped silica materials. Modell. Simul. Mater. Sci. Eng.. 2020;28
[CrossRef] [Google Scholar]
Li X., Chen W., Ma L., . Industrial wastewater advanced treatment via catalytic ozonation with an Fe-based catalyst. Chemosphere. 2018;195:336-343.
[CrossRef] [Google Scholar]
Li X., Chen W., Ma L., . Characteristics and mechanisms of catalytic ozonation with Fe-shaving-based catalyst in industrial wastewater advanced treatment. J. Clean. Prod.. 2019;222:174-181.
[CrossRef] [Google Scholar]
Li J., Song W., Yu Z., . Preparation of the Mn-Fe-Ce/γ-Al₂O₃ ternary catalyst and its catalytic performance in ozone treatment of dairy farming wastewater. Arabian J. Chem.. 2020;13:3724-3734.
[CrossRef] [Google Scholar]
Li C., Sun Z., Song A., . Flowing nitrogen atmosphere induced rich oxygen vacancies overspread the surface of TiO₂/kaolinite composite for enhanced photocatalytic activity within broad radiation spectrum. Appl. Catal. B: Environ.. 2018;236:76-87.
[CrossRef] [Google Scholar]
Li Y., Wu L., Wang Y., . γ-Al₂O₃ doped with cerium to enhance electron transfer in catalytic ozonation of phenol. J. Water Process Eng.. 2020;36
[CrossRef] [Google Scholar]
Li M., Yang K., Huang X., . Efficient degradation of trimethoprim by catalytic ozonation coupled with Mn/FeO_x-functionalized ceramic membrane: Synergic catalytic effect and enhanced anti-fouling performance. J. Colloid Interface Sci.. 2022;616:440-452.
[CrossRef] [Google Scholar]
Liang D., Hu Y., Xiao C., . Highly efficient catalytic ozonation for ammonium in water upon gamma-Al₂O₃@Fe/Mg with acidic-basic sites and oxygen vacancies. Sci. Total Environ.. 2022;834:155278
[CrossRef] [Google Scholar]
Lim S., Shi J.L., von Gunten U., . Ozonation of organic compounds in water and wastewater: a critical review. Water Res.. 2022;213:118053
[CrossRef] [Google Scholar]
Lin N., Gong Y., Wang R., . Critical review of perovskite-based materials in advanced oxidation system for wastewater treatment: design, applications and mechanisms. J. Hazard. Mater.. 2022;424:127637
[CrossRef] [Google Scholar]
Liu N., Dai W., Fei F., . Insights into the photocatalytic activation persulfate by visible light over ReS₂/MIL-88B(Fe) for highly efficient degradation of ibuprofen: combination of experimental and theoretical study. Sep. Purif. Technol.. 2022;297
[CrossRef] [Google Scholar]
Liu Z.Q., Huang C.X., Li J.Y., . Activated carbon catalytic ozonation of reverse osmosis concentrate after coagulation pretreatment from coal gasification wastewater reclamation for zero liquid discharge. J. Clean. Prod.. 2021;286:13.
[CrossRef] [Google Scholar]
Liu D., Wang C., Song Y., . Effective mineralization of quinoline and bio-treated coking wastewater by catalytic ozonation using CuFe₂O₄/Sepiolite catalyst: efficiency and mechanism. Chemosphere. 2019;227:647-656.
[CrossRef] [Google Scholar]
Liu W., Xiao K., Li J., . Efficient removal of organic contaminants in real shale gas flowback water using Fenton oxidation assisted by UV irradiation: feasibility study and process optimization. Process Saf. Environ. Prot.. 2022;158:687-697.
[CrossRef] [Google Scholar]
Long G., Chen M., Li Y., . One-pot synthesis of monolithic Mn-Ce-Zr ternary mixed oxides catalyst for the catalytic combustion of chlorobenzene. Chem. Eng. J.. 2019;360:964-973.
[CrossRef] [Google Scholar]
Ma J., Chen Y., Nie J., . Pilot-scale study on catalytic ozonation of bio-treated dyeing and finishing wastewater using recycled waste iron shavings as a catalyst. Sci. Rep.. 2018;8:7555.
[CrossRef] [Google Scholar]
Ma J., Li D., Yong X., . An ozone catalytic oxidation system for the degradation of organic compounds in secondary wastewater from refining and chemical processes. Environ. Technol.. 2022;1–11
[CrossRef] [Google Scholar]
Mathon B., Coquery M., Liu Z., . Ozonation of 47 organic micropollutants in secondary treated municipal effluents: direct and indirect kinetic reaction rates and modelling. Chemosphere. 2021;262
[CrossRef] [Google Scholar]
Mohsin M.K., Mohammed A.A., . Catalytic ozonation for removal of antibiotic oxy-tetracycline using zinc oxide nanoparticles. Appl. Water Sci.. 2021;11
[CrossRef] [Google Scholar]
Nakhate P.H., Gadipelly C.R., Joshi N.T., . Engineering aspects of catalytic ozonation for purification of real textile industry wastewater at the pilot scale. J. Ind. Eng. Chem.. 2019;69:77-89.
[CrossRef] [Google Scholar]
Nawrocki J., Kasprzyk-Hordern B., . The efficiency and mechanisms of catalytic ozonation. Appl. Catal. B: Environ.. 2010;99:27-42.
[CrossRef] [Google Scholar]
Oulego P., Collado S., Garrido L., . Wet oxidation of real coke wastewater containing high thiocyanate concentration. J. Environ. Manage.. 2014;132:16-23.
[CrossRef] [Google Scholar]
Pal P., Kumar R., . Treatment of coke wastewater: a critical review for developing sustainable management strategies. Sep. Purif. Rev.. 2014;43:89-123.
[CrossRef] [Google Scholar]
Pang Z.J., Luo P., Wei C., . In-situ growth of Co/Ni bimetallic organic frameworks on carbon spheres with catalytic ozonation performance for removal of bio-treated coking wastewater. Chemosphere. 2022;291:11.
[CrossRef] [Google Scholar]
Peng S., He X., Pan H., . Spectroscopic study on transformations of dissolved organic matter in coal-to-liquids wastewater under integrated chemical oxidation and biological treatment process. J. Environ. Sci. (China). 2018;70:206-216.
[CrossRef] [Google Scholar]
Petre A.L., Carbajo J.B., Rosal R., . Influence of water matrix on copper-catalysed continuous ozonation and related ecotoxicity. Appl. Catal. B: Environ.. 2015;163:233-240.
[CrossRef] [Google Scholar]
Qin X., Li Z., Zhu Z., . Fenton-like degradation of coke wastewater using Fe₇₈Si₈B₁₄ and Fe_73.5Nb₃Cu₁Si_13.5B₉ metallic glasses. J. Phys. Chem. Solids. 2019;133:85-91.
[CrossRef] [Google Scholar]
Qin Z., Wei C., Wei T., . Evolution of biochemical processes in coking wastewater treatment: a combined evaluation of material and energy efficiencies and secondary pollution. Sci Total Environ.. 2022;807:151072
[CrossRef] [Google Scholar]
Qu J., Li H., Liu H., . Ozonation of alachlor catalyzed by Cu/Al₂O₃ in water. Catal. Today. 2004;90:291-296.
[CrossRef] [Google Scholar]
Quintanilla A., Diaz de Tuesta J.L., Figueruelo C., . Condensation by-products in wet peroxide oxidation: fouling or catalytic promotion? part I. evidences of an autocatalytic process. Catalysts. 2019;9
[CrossRef] [Google Scholar]
Ranjbar Vakilabadi D., Hassani A.H., Omrani G., . Catalytic potential of Cu/Mg/Al-chitosan for ozonation of real landfill leachate. Process Saf. Environ. Prot.. 2017;107:227-237.
[CrossRef] [Google Scholar]
Reddy K.H.P., Kim B.S., Lam S.S., . Effective toluene oxidation under ozone over mesoporous MnO_x/gamma-Al₂O₃ catalyst prepared by solvent deficient method: Effect of Mn precursors on catalytic activity. Environ Res.. 2021;195:110876
[CrossRef] [Google Scholar]
Sani O.N., Fezabady A.A.N., Yazdani M., . Catalytic ozonation of ciprofloxacin using gamma-Al₂O₃ nanoparticles in synthetic and real wastewaters. J. Water Process Eng.. 2019;32
[CrossRef] [Google Scholar]
Sathya U., Keerthi M.N., . Evaluation of advanced oxidation processes (AOPs) integrated membrane bioreactor (MBR) for the real textile wastewater treatment. J. Environ. Manage.. 2019;246:768-775.
[CrossRef] [Google Scholar]
Shahmahdi N., Dehghanzadeh R., Aslani H., . Performance evaluation of waste iron shavings (Fe⁰) for catalytic ozonation in removal of sulfamethoxazole from municipal wastewater treatment plant effluent in a batch mode pilot plant. Chem. Eng. J.. 2020;383
[CrossRef] [Google Scholar]
Shang J., Jiang Y., Qin X., . Catalytic oxidation of Methylene Blue by Attapulgite/TiO₂. Front. Environ. Sci.. 2021;9
[CrossRef] [Google Scholar]
Shao S., Li Z., Gao K., . Preparation of Cu-MnO_X/γ-Al₂O₃ by high gravity-assisted impregnation method for heterogeneous catalytic ozonation of nitrobenzene. Sep. Purif. Technol.. 2022;280
[CrossRef] [Google Scholar]
Shao S., Li Z., Zhang J., . Preparation of Ce-MnO_X/γ-Al₂O₃ by high gravity-assisted impregnation method for efficient catalytic ozonation. Chem. Eng. Sci.. 2022;248
[CrossRef] [Google Scholar]
Sheydaei M., Haseli A., Ayoubi-Feiz B., . MoS₂/N-TiO₂/Ti mesh plate for visible-light photocatalytic ozonation of naproxen and industrial wastewater: comparative studies and artificial neural network modeling. Environ. Sci. Pollut. Res. Int.. 2022;29:22454-22468.
[CrossRef] [Google Scholar]
Sing K.S.W., Everett D.H., Haul R.A.W., . Reporting physisorption data for gas/solid systems with special reference to the determination of surface area and porosity. Pure Appl. Chem.. 1985;57:603-619.
[CrossRef] [Google Scholar]
Song J., Ma N., Chen W., . Insights into mechanism of catalytic ozonation of cinnamyl alcohol over core–shell Fe₃O₄@SiO₂@La₂O₃ catalyst. Sep. Purif. Technol.. 2022;282
[CrossRef] [Google Scholar]
Sun W., Sun Y., Zhu H., . Catalytic activity and evaluation of Fe-Mn@Bt for ozonizing coal chemical biochemical tail water. Sep. Purif. Technol.. 2020;239
[CrossRef] [Google Scholar]
Sun Z., Xia F., Lou Z., . Innovative process for total petroleum hydrocarbons reduction on oil refinery sludge through microbubble ozonation. J. Clean. Prod.. 2020;256
[CrossRef] [Google Scholar]
Tamang M., Paul K.K., . Advances in treatment of coking wastewater - a state of art review. Water Sci. Technol.. 2022;85:449-473.
[CrossRef] [Google Scholar]
Tang S., Yuan D., Zhang Q., . Fe-Mn bi-metallic oxides loaded on granular activated carbon to enhance dye removal by catalytic ozonation. Environ. Sci. Pollut. Res. Int.. 2016;23:18800-18808.
[CrossRef] [Google Scholar]
Tong S., Shi R., Zhang H., . Catalytic performance of Fe₃O₄-CoO/Al₂O₃ catalyst in ozonation of 2-(2,4-dichlorophenoxy)propionic acid, nitrobenzene and oxalic acid in water. J. Environ. Sci.. 2010;22:1623-1628.
[CrossRef] [Google Scholar]
Tu Y., Shao G., Zhang W., . The degradation of printing and dyeing wastewater by manganese-based catalysts. Sci. Total Environ.. 2022;828:154390
[CrossRef] [Google Scholar]
Tyagi M., Kumari N., Jagadevan S., . A holistic Fenton oxidation-biodegradation system for treatment of phenol from coke oven wastewater: optimization, toxicity analysis and phylogenetic analysis. J. Water Process Eng.. 2020;37:11.
[CrossRef] [Google Scholar]
Wang J., Bai Z., . Fe-based catalysts for heterogeneous catalytic ozonation of emerging contaminants in water and wastewater. Chem. Eng. J.. 2017;312:79-98.
[CrossRef] [Google Scholar]
Wang Y., Lin N., Gong Y., . Cu-Fe embedded cross-linked 3D hydrogel for enhanced reductive removal of Cr(VI): Characterization, performance, and mechanisms. Chemosphere. 2021;280:130663
[CrossRef] [Google Scholar]
Wang Y., Gong Y., Lin N., . Enhanced removal of Cr(VI) from aqueous solution by stabilized nanoscale zero valent iron and copper bimetal intercalated montmorillonite. J. Colloid Interface Sci.. 2022;606:941-952.
[CrossRef] [Google Scholar]
Wang S., Wang J., . Treatment of membrane filtration concentrate of coking wastewater using PMS/chloridion oxidation process. Chem. Eng. J.. 2020;379
[CrossRef] [Google Scholar]
Wang W., Wang L., Wang K., . Dissolved organic matter (DOM) removal from coking wastewater with efficient vanadium-titanium magnetite particle electrodes by 3D/EC/KPS system: optimization, performance, and mechanism. J. Clean. Prod.. 2021;322
[CrossRef] [Google Scholar]
Wang J., Wang X., Yu Z., . Using algae bacteria consortia to effectively treat coking wastewater: performance, microbial community, and mechanism. J. Clean. Prod.. 2022;334
[CrossRef] [Google Scholar]
Wang W., Yao H., Yue L., . Supported-catalyst CuO/AC with reduced cost and enhanced activity for the degradation of heavy oil refinery wastewater by catalytic ozonation process. Environ. Sci. Pollut. Res. Int.. 2020;27:7199-7210.
[CrossRef] [Google Scholar]
Wang J., Zhuan R., . Degradation of antibiotics by advanced oxidation processes: an overview. Sci. Total Environ.. 2020;701:135023
[CrossRef] [Google Scholar]
Xu Z., Xie M., Ben Y., . Efficiency and mechanism of atenolol decomposition in Co-FeOOH catalytic ozonation. J. Hazard. Mater.. 2019;365:146-154.
[CrossRef] [Google Scholar]
Yang X., De Buyck P.J., Zhang R., . Enhanced removal of refractory humic- and fulvic-like organics from biotreated landfill leachate by ozonation in packed bubble columns. Sci. Total Environ.. 2022;807:150762
[CrossRef] [Google Scholar]
Yang Y., Gu Y., Lin H., . Bicarbonate-enhanced iron-based Prussian blue analogs catalyze the Fenton-like degradation of p-nitrophenol. J. Colloid Interface Sci.. 2022;608:2884-2895.
[CrossRef] [Google Scholar]
Yang Y., Ji W., Li X., . Insights into the mechanism of enhanced peroxymonosulfate degraded tetracycline using metal organic framework derived carbonyl modified carbon-coated Fe(0) J. Hazard. Mater.. 2022;424:127640
[CrossRef] [Google Scholar]
Yang Y., Li X., Jie B., . Electron structure modulation and bicarbonate surrounding enhance Fenton-like reactions performance of Co-Co PBA. J. Hazard. Mater.. 2022;437:129372
[CrossRef] [Google Scholar]
Yang Y., Zhao S., Bi F., . Oxygen-vacancy-induced O₂ activation and electron-hole migration enhance photothermal catalytic toluene oxidation. Cell Rep. Phys. Sci.. 2022;3
[CrossRef] [Google Scholar]
Yang Y., Zhao S., Bi F., . Highly efficient photothermal catalysis of toluene over Co₃O₄/TiO₂ p-n heterojunction: the crucial roles of interface defects and band structure. Appl. Catal. B: Environ.. 2022;315
[CrossRef] [Google Scholar]
Yuan R., Xia Y., Wu X., . Efficient advanced treatment of coking wastewater using O₃/H₂O₂/Fe-shavings process. J. Environ. Chem. Eng.. 2022;10
[CrossRef] [Google Scholar]
Yuan Y., Xing G., Garg S., . Mechanistic insights into the catalytic ozonation process using iron oxide-impregnated activated carbon. Water Res.. 2020;177:115785
[CrossRef] [Google Scholar]
Zhang X., Bi F., Zhu Z., . The promoting effect of H₂O on rod-like MnCeO_x derived from MOFs for toluene oxidation: a combined experimental and theoretical investigation. Appl. Catal. B: Environ.. 2021;297
[CrossRef] [Google Scholar]
Zhang H., Niu J., Guo Y., . Recirculating coking by-products and waste for cost-effective activated carbon (AC) production and its application for treatment of SO₂ and wastewater in coke-making plant. J. Clean. Prod.. 2021;280
[CrossRef] [Google Scholar]
Zhang H., Wang B., Xiong M., . Process intensification of the ozone-liquid mass transfer in ultrasonic cavitation-rotational flow interaction coupled-field: optimization and application. J. Environ. Manage.. 2022;310:114710
[CrossRef] [Google Scholar]
Zhang X., Xiang S., Du Q., . Effect of calcination temperature on the structure and performance of rod-like MnCeO_x derived from MOFs catalysts. Mol. Catal.. 2022;522
[CrossRef] [Google Scholar]
Zhao K.-H., Ma Y.-L., Lin F., . Refractory organic compounds in coal chemical wastewater treatment by catalytic ozonation using Mn-Cu-Ce/Al₂O₃. Environ. Sci. Pollut. Res.. 2021;28:41504-41515.
[CrossRef] [Google Scholar]
Zhu Z., Rao R., Zhao Z., . Research progress on removal of phthalates pollutants from environment. J. Mol. Liq.. 2022;355
[CrossRef] [Google Scholar]
Zhu S., Zheng J., Xin S., . Preparation of flexible Pt/TiO₂/γ-Al₂O₃ nanofiber paper for room-temperature HCHO oxidation and particulate filtration. Chem. Eng. J.. 2022;427
[CrossRef] [Google Scholar]
Zubot W., An Z., Benally C., . Treatment of oil sands process water using petroleum coke: field pilot. J. Environ. Manage.. 2021;289
[CrossRef] [Google Scholar]

Appendix A

Supplementary material

Supplementary data to this article can be found online at https://doi.org/10.1016/j.arabjc.2022.104415.

Appendix A

Supplementary material

The following are the Supplementary data to this article:

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[1] AHA-AWWA-WEF, 1998. Standard Methods for the Examination of Water and Wastewater. 20th ed. American Public Health Association. Washington, DC

[2] An W., Wang H., Yang T., . Enriched photocatalysis-Fenton synergistic degradation of organic pollutants and coking wastewater via surface oxygen vacancies over Fe-BiOBr composites. Chem. Eng. J.. 2023;451
[CrossRef] [Google Scholar]

[3] Bokhimi X., Toledo J.A., Navarrete J., . Thermal evolution in air and argon of nanocrystalline MoS₂ synthesized under hydrothermal conditions. Int. J. Hydrogen Energy. 2001;26:1271-1277.
[CrossRef] [Google Scholar]

[4] Bulla D.A.P., Li W.-T., Charles C., . Deposition and characterization of silica-based films by helicon-activated reactive evaporation applied to optical waveguide fabrication. Appl. Opt.. 2004;43:2978-2985.
[CrossRef] [Google Scholar]

[5] Cai Q.Q., Wu M.Y., Li R., . Potential of combined advanced oxidation – biological process for cost-effective organic matters removal in reverse osmosis concentrate produced from industrial wastewater reclamation: screening of AOP pre-treatment technologies. Chem. Eng. J.. 2020;389
[CrossRef] [Google Scholar]

[6] Chen C., Chen H., Guo X., . Advanced ozone treatment of heavy oil refining wastewater by activated carbon supported iron oxide. J. Ind. Eng. Chem.. 2014;20:2782-2791.
[CrossRef] [Google Scholar]

[7] Chen C., Yoza B.A., Wang Y., . Catalytic ozonation of petroleum refinery wastewater utilizing Mn-Fe-Cu/Al₂O₃ catalyst. Environ Sci Pollut Res Int.. 2015;22:5552-5562.
[CrossRef] [Google Scholar]

[8] Chen C., Li Y., Ma W., . Mn-Fe-Mg-Ce loaded Al₂O₃ catalyzed ozonation for mineralization of refractory organic chemicals in petroleum refinery wastewater. Sep. Purif. Technol.. 2017;183:1-10.
[CrossRef] [Google Scholar]

[9] Chen J., Tu Y., Shao G., . Catalytic ozonation performance of calcium-loaded catalyst (Ca-C/Al₂O₃) for effective treatment of high salt organic wastewater. Sep. Purif. Technol.. 2022;301
[CrossRef] [Google Scholar]

[10] Chen K.-C., Wang Y.-H., . The effects of Fe–Mn oxide and TiO₂/α-Al₂O₃ on the formation of disinfection by-products in catalytic ozonation. Chem. Eng. J.. 2014;253:84-92.
[CrossRef] [Google Scholar]

[11] Chen X., Wang C., Jiang L., . Pilot-scale catalytic ozonation pretreatment for improving the biodegradability of fixed-bed coal gasification wastewater. Process Saf. Environ. Prot.. 2021;148:13-19.
[CrossRef] [Google Scholar]

[12] China, M. o. E. P. o. t. P. s. R. o., 2012. Emission standard of pollutants for coking chemical industry (GB 16171-2012). General Administration of Quality Supervision, Inspection and Quarantine of the People’s Republic of China. URL: http://www.mee.gov.cn/ywgz/fgbz/bz/bzwb/shjbh/swrwpfbz/201207/t20120731_234146.shtml [In Chinese],

[13] Chu L., Wang J., Dong J., . Treatment of coking wastewater by an advanced Fenton oxidation process using iron powder and hydrogen peroxide. Chemosphere. 2012;86:409-414.
[CrossRef] [Google Scholar]

[14] Coha M., Farinelli G., Tiraferri A., . Advanced oxidation processes in the removal of organic substances from produced water: potential, configurations, and research needs. Chem. Eng. J.. 2021;414
[CrossRef] [Google Scholar]

[15] Du X., Zhang Y., Si F., . Persulfate non-radical activation by nano-CuO for efficient removal of chlorinated organic compounds: reduced graphene oxide-assisted and CuO (0 0 1) facet-dependent. Chem. Eng. J.. 2019;356:178-189.
[CrossRef] [Google Scholar]

[16] Ederer J., Janoš P., Šťastný M., . Nanocrystalline cerium oxide for catalytic degradation of paraoxon methyl: Influence of CeO₂ surface properties. J. Environ. Chem. Eng.. 2021;9
[CrossRef] [Google Scholar]

[17] Faghihinezhad M., Baghdadi M., Shahin M.S., . Catalytic ozonation of real textile wastewater by magnetic oxidized g-C₃N₄ modified with Al₂O₃ nanoparticles as a novel catalyst. Sep. Purif. Technol.. 2022;283
[CrossRef] [Google Scholar]

[18] Fu L., Wu C., Zhou Y., . Ozonation reactivity characteristics of dissolved organic matter in secondary petrochemical wastewater by single ozone, ozone/H₂O₂, and ozone/catalyst. Chemosphere. 2019;233:34-43.
[CrossRef] [Google Scholar]

[19] Gao M.-J., Wang X.-D., Guo M., . Contrast on COD photo-degradation in coking wastewater catalyzed by TiO₂ and TiO₂–TiO₂ nanorod arrays. Catal. Today. 2011;174:79-87.
[CrossRef] [Google Scholar]

[20] Gao Y.-Q., Zhou J.-Q., Rao Y.-Y., . Comparative study of degradation of ketoprofen and paracetamol by ultrasonic irradiation: mechanism, toxicity and DBP formation. Ultrason. Sonochem.. 2022;82:105906
[CrossRef] [Google Scholar]

[21] Guo Q., Liu Y., Qi G., . Study of low temperature combustion performance for composite metal catalysts prepared via rotating packed bed. Energy. 2019;179:431-441.
[CrossRef] [Google Scholar]

[22] Guo Y., Zhang Y., Yu G., . Revisiting the role of reactive oxygen species for pollutant abatement during catalytic ozonation: The probe approach versus the scavenger approach. Appl. Catal. B: Environ.. 2021;280
[CrossRef] [Google Scholar]

[23] Guo Y., Long J., Huang J., . Can the commonly used quenching method really evaluate the role of reactive oxygen species in pollutant abatement during catalytic ozonation? Water Res.. 2022;215:118275
[CrossRef] [Google Scholar]

[24] Guo L., Zhang M., Xie S., . Catalytic ozonation of high-salinity wastewater using salt-resistant catalyst Fe-Bi@γ-Al₂O₃. J. Water Process Eng.. 2022;49
[CrossRef] [Google Scholar]

[25] He C., Wang J., Wang C., . Catalytic ozonation of bio-treated coking wastewater in continuous pilot- and full-scale system: efficiency, catalyst deactivation and in-situ regeneration. Water Res.. 2020;183
[CrossRef] [Google Scholar]

[26] He C., He X., Li J., . The spectral characteristics of biochar-derived dissolved organic matter at different pyrolysis temperatures. J. Environ. Chem. Eng.. 2021;9
[CrossRef] [Google Scholar]

[27] He L., Wang C., Chen X., . Preparation of Tin-Antimony anode modified with carbon nanotubes for electrochemical treatment of coking wastewater. Chemosphere. 2022;288:132362
[CrossRef] [Google Scholar]

[28] Hou S., Jia S., Jia J., . Fe₃O₄ nanoparticles loading on cow dung based activated carbon as an efficient catalyst for catalytic microbubble ozonation of biologically pretreated coal gasification wastewater. J Environ Manage.. 2020;267:110615
[CrossRef] [Google Scholar]

[29] Hu Y., Yu F., Bai Z., . Preparation of Fe-loaded needle coke particle electrodes and utilisation in three-dimensional electro-Fenton oxidation of coking wastewater. Chemosphere. 2022;308:136544
[CrossRef] [Google Scholar]

[30] Huang Y., Liang M., Ma L., . Ozonation catalysed by ferrosilicon for the degradation of ibuprofen in water. Environ Pollut.. 2021;268:115722
[CrossRef] [Google Scholar]

[31] Huang G., Pan F., Fan G., . Application of heterogeneous catalytic ozonation as a tertiary treatment of effluent of biologically treated tannery wastewater. J. Environ. Sci. Health Part a-Toxic/Hazard. Substances Environ. Eng.. 2016;51:626-633.
[CrossRef] [Google Scholar]

[32] Huong P.T.L., Huy L.T., Phan V.N., . Application of graphene oxide-MnFe₂O₄ magnetic nanohybrids as magnetically separable adsorbent for highly efficient removal of arsenic from water. J. Electron. Mater.. 2016;45:2372-2380.
[CrossRef] [Google Scholar]

[33] Jayapal M., Jagadeesan H., Krishnasamy V., . Demonstration of a plant-microbe integrated system for treatment of real-time textile industry wastewater. Environ. Pollut.. 2022;302:119009
[CrossRef] [Google Scholar]

[34] Jothinathan L., Cai Q.Q., Ong S.L., . Organics removal in high strength petrochemical wastewater with combined microbubble-catalytic ozonation process. Chemosphere. 2021;263
[CrossRef] [Google Scholar]

[35] Jothinathan L., Cai Q.Q., Ong S.L., . Fe-Mn doped powdered activated carbon pellet as ozone catalyst for cost-effective phenolic wastewater treatment: mechanism studies and phenol by-products elimination. J. Hazard. Mater.. 2022;424:127483
[CrossRef] [Google Scholar]

[36] Ke P., Yue K., You Z., . Investigation on structure and luminescence properties of Yb3+-doped silica materials. Modell. Simul. Mater. Sci. Eng.. 2020;28
[CrossRef] [Google Scholar]

[37] Li X., Chen W., Ma L., . Industrial wastewater advanced treatment via catalytic ozonation with an Fe-based catalyst. Chemosphere. 2018;195:336-343.
[CrossRef] [Google Scholar]

[38] Li X., Chen W., Ma L., . Characteristics and mechanisms of catalytic ozonation with Fe-shaving-based catalyst in industrial wastewater advanced treatment. J. Clean. Prod.. 2019;222:174-181.
[CrossRef] [Google Scholar]

[39] Li J., Song W., Yu Z., . Preparation of the Mn-Fe-Ce/γ-Al₂O₃ ternary catalyst and its catalytic performance in ozone treatment of dairy farming wastewater. Arabian J. Chem.. 2020;13:3724-3734.
[CrossRef] [Google Scholar]

[40] Li C., Sun Z., Song A., . Flowing nitrogen atmosphere induced rich oxygen vacancies overspread the surface of TiO₂/kaolinite composite for enhanced photocatalytic activity within broad radiation spectrum. Appl. Catal. B: Environ.. 2018;236:76-87.
[CrossRef] [Google Scholar]

[41] Li Y., Wu L., Wang Y., . γ-Al₂O₃ doped with cerium to enhance electron transfer in catalytic ozonation of phenol. J. Water Process Eng.. 2020;36
[CrossRef] [Google Scholar]

[42] Li M., Yang K., Huang X., . Efficient degradation of trimethoprim by catalytic ozonation coupled with Mn/FeO_x-functionalized ceramic membrane: Synergic catalytic effect and enhanced anti-fouling performance. J. Colloid Interface Sci.. 2022;616:440-452.
[CrossRef] [Google Scholar]

[43] Liang D., Hu Y., Xiao C., . Highly efficient catalytic ozonation for ammonium in water upon gamma-Al₂O₃@Fe/Mg with acidic-basic sites and oxygen vacancies. Sci. Total Environ.. 2022;834:155278
[CrossRef] [Google Scholar]

[44] Lim S., Shi J.L., von Gunten U., . Ozonation of organic compounds in water and wastewater: a critical review. Water Res.. 2022;213:118053
[CrossRef] [Google Scholar]

[45] Lin N., Gong Y., Wang R., . Critical review of perovskite-based materials in advanced oxidation system for wastewater treatment: design, applications and mechanisms. J. Hazard. Mater.. 2022;424:127637
[CrossRef] [Google Scholar]

[46] Liu N., Dai W., Fei F., . Insights into the photocatalytic activation persulfate by visible light over ReS₂/MIL-88B(Fe) for highly efficient degradation of ibuprofen: combination of experimental and theoretical study. Sep. Purif. Technol.. 2022;297
[CrossRef] [Google Scholar]

[47] Liu Z.Q., Huang C.X., Li J.Y., . Activated carbon catalytic ozonation of reverse osmosis concentrate after coagulation pretreatment from coal gasification wastewater reclamation for zero liquid discharge. J. Clean. Prod.. 2021;286:13.
[CrossRef] [Google Scholar]

[48] Liu D., Wang C., Song Y., . Effective mineralization of quinoline and bio-treated coking wastewater by catalytic ozonation using CuFe₂O₄/Sepiolite catalyst: efficiency and mechanism. Chemosphere. 2019;227:647-656.
[CrossRef] [Google Scholar]

[49] Liu W., Xiao K., Li J., . Efficient removal of organic contaminants in real shale gas flowback water using Fenton oxidation assisted by UV irradiation: feasibility study and process optimization. Process Saf. Environ. Prot.. 2022;158:687-697.
[CrossRef] [Google Scholar]

[50] Long G., Chen M., Li Y., . One-pot synthesis of monolithic Mn-Ce-Zr ternary mixed oxides catalyst for the catalytic combustion of chlorobenzene. Chem. Eng. J.. 2019;360:964-973.
[CrossRef] [Google Scholar]

[51] Ma J., Chen Y., Nie J., . Pilot-scale study on catalytic ozonation of bio-treated dyeing and finishing wastewater using recycled waste iron shavings as a catalyst. Sci. Rep.. 2018;8:7555.
[CrossRef] [Google Scholar]

[52] Ma J., Li D., Yong X., . An ozone catalytic oxidation system for the degradation of organic compounds in secondary wastewater from refining and chemical processes. Environ. Technol.. 2022;1–11
[CrossRef] [Google Scholar]

[53] Mathon B., Coquery M., Liu Z., . Ozonation of 47 organic micropollutants in secondary treated municipal effluents: direct and indirect kinetic reaction rates and modelling. Chemosphere. 2021;262
[CrossRef] [Google Scholar]

[54] Mohsin M.K., Mohammed A.A., . Catalytic ozonation for removal of antibiotic oxy-tetracycline using zinc oxide nanoparticles. Appl. Water Sci.. 2021;11
[CrossRef] [Google Scholar]

[55] Nakhate P.H., Gadipelly C.R., Joshi N.T., . Engineering aspects of catalytic ozonation for purification of real textile industry wastewater at the pilot scale. J. Ind. Eng. Chem.. 2019;69:77-89.
[CrossRef] [Google Scholar]

[56] Nawrocki J., Kasprzyk-Hordern B., . The efficiency and mechanisms of catalytic ozonation. Appl. Catal. B: Environ.. 2010;99:27-42.
[CrossRef] [Google Scholar]

[57] Oulego P., Collado S., Garrido L., . Wet oxidation of real coke wastewater containing high thiocyanate concentration. J. Environ. Manage.. 2014;132:16-23.
[CrossRef] [Google Scholar]

[58] Pal P., Kumar R., . Treatment of coke wastewater: a critical review for developing sustainable management strategies. Sep. Purif. Rev.. 2014;43:89-123.
[CrossRef] [Google Scholar]

[59] Pang Z.J., Luo P., Wei C., . In-situ growth of Co/Ni bimetallic organic frameworks on carbon spheres with catalytic ozonation performance for removal of bio-treated coking wastewater. Chemosphere. 2022;291:11.
[CrossRef] [Google Scholar]

[60] Peng S., He X., Pan H., . Spectroscopic study on transformations of dissolved organic matter in coal-to-liquids wastewater under integrated chemical oxidation and biological treatment process. J. Environ. Sci. (China). 2018;70:206-216.
[CrossRef] [Google Scholar]

[61] Petre A.L., Carbajo J.B., Rosal R., . Influence of water matrix on copper-catalysed continuous ozonation and related ecotoxicity. Appl. Catal. B: Environ.. 2015;163:233-240.
[CrossRef] [Google Scholar]

[62] Qin X., Li Z., Zhu Z., . Fenton-like degradation of coke wastewater using Fe₇₈Si₈B₁₄ and Fe_73.5Nb₃Cu₁Si_13.5B₉ metallic glasses. J. Phys. Chem. Solids. 2019;133:85-91.
[CrossRef] [Google Scholar]

[63] Qin Z., Wei C., Wei T., . Evolution of biochemical processes in coking wastewater treatment: a combined evaluation of material and energy efficiencies and secondary pollution. Sci Total Environ.. 2022;807:151072
[CrossRef] [Google Scholar]

[64] Qu J., Li H., Liu H., . Ozonation of alachlor catalyzed by Cu/Al₂O₃ in water. Catal. Today. 2004;90:291-296.
[CrossRef] [Google Scholar]

[65] Quintanilla A., Diaz de Tuesta J.L., Figueruelo C., . Condensation by-products in wet peroxide oxidation: fouling or catalytic promotion? part I. evidences of an autocatalytic process. Catalysts. 2019;9
[CrossRef] [Google Scholar]

[66] Ranjbar Vakilabadi D., Hassani A.H., Omrani G., . Catalytic potential of Cu/Mg/Al-chitosan for ozonation of real landfill leachate. Process Saf. Environ. Prot.. 2017;107:227-237.
[CrossRef] [Google Scholar]

[67] Reddy K.H.P., Kim B.S., Lam S.S., . Effective toluene oxidation under ozone over mesoporous MnO_x/gamma-Al₂O₃ catalyst prepared by solvent deficient method: Effect of Mn precursors on catalytic activity. Environ Res.. 2021;195:110876
[CrossRef] [Google Scholar]

[68] Sani O.N., Fezabady A.A.N., Yazdani M., . Catalytic ozonation of ciprofloxacin using gamma-Al₂O₃ nanoparticles in synthetic and real wastewaters. J. Water Process Eng.. 2019;32
[CrossRef] [Google Scholar]

[69] Sathya U., Keerthi M.N., . Evaluation of advanced oxidation processes (AOPs) integrated membrane bioreactor (MBR) for the real textile wastewater treatment. J. Environ. Manage.. 2019;246:768-775.
[CrossRef] [Google Scholar]

[70] Shahmahdi N., Dehghanzadeh R., Aslani H., . Performance evaluation of waste iron shavings (Fe⁰) for catalytic ozonation in removal of sulfamethoxazole from municipal wastewater treatment plant effluent in a batch mode pilot plant. Chem. Eng. J.. 2020;383
[CrossRef] [Google Scholar]

[71] Shang J., Jiang Y., Qin X., . Catalytic oxidation of Methylene Blue by Attapulgite/TiO₂. Front. Environ. Sci.. 2021;9
[CrossRef] [Google Scholar]

[72] Shao S., Li Z., Gao K., . Preparation of Cu-MnO_X/γ-Al₂O₃ by high gravity-assisted impregnation method for heterogeneous catalytic ozonation of nitrobenzene. Sep. Purif. Technol.. 2022;280
[CrossRef] [Google Scholar]

[73] Shao S., Li Z., Zhang J., . Preparation of Ce-MnO_X/γ-Al₂O₃ by high gravity-assisted impregnation method for efficient catalytic ozonation. Chem. Eng. Sci.. 2022;248
[CrossRef] [Google Scholar]

[74] Sheydaei M., Haseli A., Ayoubi-Feiz B., . MoS₂/N-TiO₂/Ti mesh plate for visible-light photocatalytic ozonation of naproxen and industrial wastewater: comparative studies and artificial neural network modeling. Environ. Sci. Pollut. Res. Int.. 2022;29:22454-22468.
[CrossRef] [Google Scholar]

[75] Sing K.S.W., Everett D.H., Haul R.A.W., . Reporting physisorption data for gas/solid systems with special reference to the determination of surface area and porosity. Pure Appl. Chem.. 1985;57:603-619.
[CrossRef] [Google Scholar]

[76] Song J., Ma N., Chen W., . Insights into mechanism of catalytic ozonation of cinnamyl alcohol over core–shell Fe₃O₄@SiO₂@La₂O₃ catalyst. Sep. Purif. Technol.. 2022;282
[CrossRef] [Google Scholar]

[77] Sun W., Sun Y., Zhu H., . Catalytic activity and evaluation of Fe-Mn@Bt for ozonizing coal chemical biochemical tail water. Sep. Purif. Technol.. 2020;239
[CrossRef] [Google Scholar]

[78] Sun Z., Xia F., Lou Z., . Innovative process for total petroleum hydrocarbons reduction on oil refinery sludge through microbubble ozonation. J. Clean. Prod.. 2020;256
[CrossRef] [Google Scholar]

[79] Tamang M., Paul K.K., . Advances in treatment of coking wastewater - a state of art review. Water Sci. Technol.. 2022;85:449-473.
[CrossRef] [Google Scholar]

[80] Tang S., Yuan D., Zhang Q., . Fe-Mn bi-metallic oxides loaded on granular activated carbon to enhance dye removal by catalytic ozonation. Environ. Sci. Pollut. Res. Int.. 2016;23:18800-18808.
[CrossRef] [Google Scholar]

[81] Tong S., Shi R., Zhang H., . Catalytic performance of Fe₃O₄-CoO/Al₂O₃ catalyst in ozonation of 2-(2,4-dichlorophenoxy)propionic acid, nitrobenzene and oxalic acid in water. J. Environ. Sci.. 2010;22:1623-1628.
[CrossRef] [Google Scholar]

[82] Tu Y., Shao G., Zhang W., . The degradation of printing and dyeing wastewater by manganese-based catalysts. Sci. Total Environ.. 2022;828:154390
[CrossRef] [Google Scholar]

[83] Tyagi M., Kumari N., Jagadevan S., . A holistic Fenton oxidation-biodegradation system for treatment of phenol from coke oven wastewater: optimization, toxicity analysis and phylogenetic analysis. J. Water Process Eng.. 2020;37:11.
[CrossRef] [Google Scholar]

[84] Wang J., Bai Z., . Fe-based catalysts for heterogeneous catalytic ozonation of emerging contaminants in water and wastewater. Chem. Eng. J.. 2017;312:79-98.
[CrossRef] [Google Scholar]

[85] Wang Y., Lin N., Gong Y., . Cu-Fe embedded cross-linked 3D hydrogel for enhanced reductive removal of Cr(VI): Characterization, performance, and mechanisms. Chemosphere. 2021;280:130663
[CrossRef] [Google Scholar]

[86] Wang Y., Gong Y., Lin N., . Enhanced removal of Cr(VI) from aqueous solution by stabilized nanoscale zero valent iron and copper bimetal intercalated montmorillonite. J. Colloid Interface Sci.. 2022;606:941-952.
[CrossRef] [Google Scholar]

[87] Wang S., Wang J., . Treatment of membrane filtration concentrate of coking wastewater using PMS/chloridion oxidation process. Chem. Eng. J.. 2020;379
[CrossRef] [Google Scholar]

[88] Wang W., Wang L., Wang K., . Dissolved organic matter (DOM) removal from coking wastewater with efficient vanadium-titanium magnetite particle electrodes by 3D/EC/KPS system: optimization, performance, and mechanism. J. Clean. Prod.. 2021;322
[CrossRef] [Google Scholar]

[89] Wang J., Wang X., Yu Z., . Using algae bacteria consortia to effectively treat coking wastewater: performance, microbial community, and mechanism. J. Clean. Prod.. 2022;334
[CrossRef] [Google Scholar]

[90] Wang W., Yao H., Yue L., . Supported-catalyst CuO/AC with reduced cost and enhanced activity for the degradation of heavy oil refinery wastewater by catalytic ozonation process. Environ. Sci. Pollut. Res. Int.. 2020;27:7199-7210.
[CrossRef] [Google Scholar]

[91] Wang J., Zhuan R., . Degradation of antibiotics by advanced oxidation processes: an overview. Sci. Total Environ.. 2020;701:135023
[CrossRef] [Google Scholar]

[92] Xu Z., Xie M., Ben Y., . Efficiency and mechanism of atenolol decomposition in Co-FeOOH catalytic ozonation. J. Hazard. Mater.. 2019;365:146-154.
[CrossRef] [Google Scholar]

[93] Yang X., De Buyck P.J., Zhang R., . Enhanced removal of refractory humic- and fulvic-like organics from biotreated landfill leachate by ozonation in packed bubble columns. Sci. Total Environ.. 2022;807:150762
[CrossRef] [Google Scholar]

[94] Yang Y., Gu Y., Lin H., . Bicarbonate-enhanced iron-based Prussian blue analogs catalyze the Fenton-like degradation of p-nitrophenol. J. Colloid Interface Sci.. 2022;608:2884-2895.
[CrossRef] [Google Scholar]

[95] Yang Y., Ji W., Li X., . Insights into the mechanism of enhanced peroxymonosulfate degraded tetracycline using metal organic framework derived carbonyl modified carbon-coated Fe(0) J. Hazard. Mater.. 2022;424:127640
[CrossRef] [Google Scholar]

[96] Yang Y., Li X., Jie B., . Electron structure modulation and bicarbonate surrounding enhance Fenton-like reactions performance of Co-Co PBA. J. Hazard. Mater.. 2022;437:129372
[CrossRef] [Google Scholar]

[97] Yang Y., Zhao S., Bi F., . Oxygen-vacancy-induced O₂ activation and electron-hole migration enhance photothermal catalytic toluene oxidation. Cell Rep. Phys. Sci.. 2022;3
[CrossRef] [Google Scholar]

[98] Yang Y., Zhao S., Bi F., . Highly efficient photothermal catalysis of toluene over Co₃O₄/TiO₂ p-n heterojunction: the crucial roles of interface defects and band structure. Appl. Catal. B: Environ.. 2022;315
[CrossRef] [Google Scholar]

[99] Yuan R., Xia Y., Wu X., . Efficient advanced treatment of coking wastewater using O₃/H₂O₂/Fe-shavings process. J. Environ. Chem. Eng.. 2022;10
[CrossRef] [Google Scholar]

[100] Yuan Y., Xing G., Garg S., . Mechanistic insights into the catalytic ozonation process using iron oxide-impregnated activated carbon. Water Res.. 2020;177:115785
[CrossRef] [Google Scholar]

[101] Zhang X., Bi F., Zhu Z., . The promoting effect of H₂O on rod-like MnCeO_x derived from MOFs for toluene oxidation: a combined experimental and theoretical investigation. Appl. Catal. B: Environ.. 2021;297
[CrossRef] [Google Scholar]

[102] Zhang H., Niu J., Guo Y., . Recirculating coking by-products and waste for cost-effective activated carbon (AC) production and its application for treatment of SO₂ and wastewater in coke-making plant. J. Clean. Prod.. 2021;280
[CrossRef] [Google Scholar]

[103] Zhang H., Wang B., Xiong M., . Process intensification of the ozone-liquid mass transfer in ultrasonic cavitation-rotational flow interaction coupled-field: optimization and application. J. Environ. Manage.. 2022;310:114710
[CrossRef] [Google Scholar]

[104] Zhang X., Xiang S., Du Q., . Effect of calcination temperature on the structure and performance of rod-like MnCeO_x derived from MOFs catalysts. Mol. Catal.. 2022;522
[CrossRef] [Google Scholar]

[105] Zhao K.-H., Ma Y.-L., Lin F., . Refractory organic compounds in coal chemical wastewater treatment by catalytic ozonation using Mn-Cu-Ce/Al₂O₃. Environ. Sci. Pollut. Res.. 2021;28:41504-41515.
[CrossRef] [Google Scholar]

[106] Zhu Z., Rao R., Zhao Z., . Research progress on removal of phthalates pollutants from environment. J. Mol. Liq.. 2022;355
[CrossRef] [Google Scholar]

[107] Zhu S., Zheng J., Xin S., . Preparation of flexible Pt/TiO₂/γ-Al₂O₃ nanofiber paper for room-temperature HCHO oxidation and particulate filtration. Chem. Eng. J.. 2022;427
[CrossRef] [Google Scholar]

[108] Zubot W., An Z., Benally C., . Treatment of oil sands process water using petroleum coke: field pilot. J. Environ. Manage.. 2021;289
[CrossRef] [Google Scholar]

Fe-Mn-Cu-Ce/Al2O3 as an efficient catalyst for catalytic ozonation of bio-treated coking wastewater: Characteristics, efficiency, and mechanism

Abstract

Abstract

Keywords

Fe-Mn-Cu-Ce/Al2O3

Catalytic ozonation

Coking wastewater

Catalytic mechanism

Pilot-scale study

Nomenclature

1 Introduction

2 Materials and methods

2.1 Experimental materials

2.2 Preparation of catalysts

2.3 Analytical methods

2.4 Experimental system

3 Results and discussion

3.1 Comparison of COD removal efficiency by different reaction systems

3.2 Characterization of catalysts

3.3 Parameter optimization of catalytic ozonation process

3.3.1 Effect of catalyst dosage

3.3.2 Effect of pH

3.3.3 Effect of reflux ratio

3.4 Catalytic mechanism

3.4.1 Ozone utilization rate and active site

3.4.2 Detection of reactive oxygen species

3.4.3 Possible reaction mechanism

3.5 Pilot test of catalytic ozonation degradation of coking wastewater

3.5.1 Parameter optimization of catalytic ozonation process

3.5.1.1 Effect of initial pollutant concentration

3.5.1.2 Effect of ozone concentration

3.5.1.3 Effect of gas flow

3.5.2 Reusability of the catalyst

3.5.3 Operation cost of catalytic ozonation in the pilot-scale study

3.6 Kinetic analysis

3.7 Removal behavior of organic pollutants

3.7.1 3D-EEM analysis

3.7.2 GC–MS analysis

3.7.3 Analysis in conventional water quality indexes

3.8 Scope for future work

4 Conclusions

Acknowledgement

Declaration of Competing Interest

References

Appendix A

Supplementary material

Appendix A

Supplementary material

Supplementary data 1

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Fe-Mn-Cu-Ce/Al₂O₃ as an efficient catalyst for catalytic ozonation of bio-treated coking wastewater: Characteristics, efficiency, and mechanism