5.2
Impact Factor
Generic selectors
Exact matches only
Search in title
Search in content
Post Type Selectors
Search in posts
Search in pages
Filter by Categories
Corrigendum
Current Issue
Editorial
Erratum
Full Length Article
Full lenth article
Letter to Editor
Original Article
Research article
Retraction notice
Review
Review Article
SPECIAL ISSUE: ENVIRONMENTAL CHEMISTRY
5.3
Impact Factor
Generic selectors
Exact matches only
Search in title
Search in content
Post Type Selectors
Search in posts
Search in pages
Filter by Categories
Corrigendum
Current Issue
Editorial
Erratum
Full Length Article
Full lenth article
Letter to Editor
Original Article
Research article
Retraction notice
Review
Review Article
SPECIAL ISSUE: ENVIRONMENTAL CHEMISTRY
View/Download PDF

Translate this page into:

Original Article
2025
:18;
1282025
doi:
10.25259/AJC_128_2025

Synthesis and investigation of TiO2/Na-mordenite nanocomposite for photocatalytic degradation of acid red 57 dye: Experimental design optimization

, , , , , , ,
aDepartment of Chemistry, College of Science, University of Tabuk, Tabuk, Saudi Arabia
bDepartment of Chemistry, Faculty of Sciences, Umm Al-Qura University, Makkah, Saudi Arabia
cDepartment of Physical Sciences, Chemistry Division, College of Science, Jazan University, P.O. Box.114, Jazan 45142, Saudi Arabia
dDepartment of Chemistry, Al-Qunfudah University Collage, Umm Al-Qura University, Al-Qunfudah 1109, Saudi Arabia
eDepartment of Environment and Health Research, Umm Al-Qura University, Makkah, Saudi Arabia

* Corresponding author: E-mail address: ffshaaban@uqu.edu.sa (F. Shaaban)

Received: , Accepted: ,
© 2025 Arabian Journal of Chemistry - Published by Scientific Scholar
Licence
This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-Share Alike 4.0 License, which allows others to remix, transform, and build upon the work non-commercially, as long as the author is credited and the new creations are licensed under the identical terms.

Abstract

This study described the creation of a nanocomposite (TiO2/NaMOR) based on Na-mordenite (NaMOR) and anatase (TiO2). The prepared material was characterized by powder X-ray diffraction (PXRD), Brunauer–Emmett–Teller (BET) theory, Scanning electron microscope (SEM), Diffuse reflectance spectroscopy (DRS), Fourier transform infrared (FTIR), and X-ray photoelectron spectroscopy (XPS). Under UV irradiation, photocatalytic processes were evaluated in the degradation of acid red 57 dye (AR57). Within 90 mins of irradiation, TiO2/NaMOR exhibits the highest photocatalytic dye degradation efficacy of 91.75% for AR57 dye. The effects of operating parameters, such as catalyst dosage, pH, and starting dye concentration, were assessed. The degradation rate of the dye rose as the dosage of TiO2/NaMOR catalyst was increased, while the dye’s original concentration dropped, based on the results. The study of the kinetics of the photodegradation of AR57 by TiO2/NaMOR indicated a pseudo-first-order response, with an R2 value of 0.989. The impact of scavengers on reactive species during degradation was also examined, revealing that (•O2−) and (•OH) radicals were the primary classes involved. Terephthalic acid was used as an inquiry molecule in photoluminescence studies to ascertain the production of •OH free radicals because of irradiation. A Box-Behnken model was constructed based on three factors, and response surface methodology (RSM) was used to verify the best conditions for the photodegradation of AR57 by TiO2/NaMOR. The TiO2/NaMOR composite’s promise as a promising catalyst for photocatalytic applications has been amply proven by this work.

Keywords

Acid red 57
Nanocomposite
Optimization
Photocatalytic degradation
TiO2/NaMOR

1. Introduction

Environmental contamination rose as industry grew, creating a major global issue that needs to be addressed right away. Dyes, which are frequently created by industrial discharge wastewater, invariably contaminate aquatic bodies. Synthetic dyes are continuously produced on a wide scale by a variety of industries, including textiles, food, cosmetics, soaps & detergents, medicines, paints, plastics, paper, and printing. As a result, polluted, colored effluents with stable, non-biodegradable dyes are produced [1]. When industrial dye pollutants are discharged into aquatic systems, major health and environmental problems result. These problems include toxicity to living organisms, water turbidity that alters oxygen levels and hinders light penetration, kidney and liver failure, problems with the reproductive and central nervous systems, and potential mutagenic and carcinogenic consequences [2]. Effective treatment of effluents prior to their discharge is crucial to safeguarding the environment and human health. Treatment technologies for dye-containing effluents include chemical, physical, or biological methods, either in combination or alone. Conventional wastewater treatments, such as coagulation, precipitation, ozonation, reverse osmosis, and ultrafiltration, are commercially insufficient and can cause secondary pollution [3]. However, advanced oxidation chemical methods, mainly photocatalysis, promise to minimize energy consumption and cost. These methods effectively remove 70 to 80% of day-containing wastewater without producing toxic byproducts [4]. Photocatalysis technology has proved effective for environmental remediation, using renewable solar energy to degrade pollutants into harmless constituents [5]. Catalysts activate via solar energy, where photons excite band-gap electrons from valence to conductance bands. This generates oxidative free radicals, which degrade chemical and microorganism pollutants [6]. Large-scale photocatalyst production, stability, and light sensitivity enhancement are still difficult tasks. To cut costs, the new study looks at ways to enhance light harvesting, use hybrid catalysts, and increase the effectiveness of charge separation [7].

Titanium oxide (TiO2) is a common semiconductor photocatalyst that offers chemical stability, affordability, non-toxicity, natural abundance, ease of manufacture, and the absence of secondary pollution [8]. Vairos TiO2 nanomaterials with different geometries are fabricated and investigated, showing appealing performance in various applications [9]. Additionally, by treating TiO2 surfaces, scientists create hypered nanomaterials with a variety of compositions, morphologies, and sizes that improve functioning [10]. Researchers meticulously prepared TiO2 nanocomposites with high surface area, tunable pore structures, accessible active site channels for analyte diffusion, and enhanced light harvesting and optical properties [11]. These properties improve adsorption capacity and photocatalytic performance, enhancing the elimination of organic pollutants [12]. Peng and others prepared bifunctional nanomaterials consisting of mesoporous TiO2 and AgxCuy alloy hybrids for monitoring ampicillin in water. It showed photocatalytic degradation higher than the commercial nonporous P25-Ag-Cu [13]. TiO2 catalysts embedded in support materials create a promising one-step water treatment method that eliminates the need for filtration. Nanohybrid TiO2 with nanoporous material composition facilitates efficient electron migration, trapping electrons to prevent recombination. This overcomes TiO2’s low charge carrier-separation capacity and narrow light spectrum utilization due to its band gap limitations (3-3.2 eV) [14]. Nevertheless, immobilized TiO2, unlike its suspension form, faces challenges such as hindered active site surfaces, loss of porosity, and low photocatalytic activity due to mass transfer resistance [15]. Guesh and colleagues used zeolite support to achieve efficient photocatalytic degradation of methyl orange by dispersing TiO2 particles without calcination, maintaining a good trapping effect and small crystal domains with great surface area [15,16]. Fischer et al. showed that TiO2’s crystallinity enhances its photolytic activity more significantly than the expected enhancement by the degree of its uniform distribution on a porous support [16,17].

Porous materials with a large surface area have gained interest as structural support for photocatalysts used in water purification [18]. Zeolites are versatile, multifunctional materials that can be used as sorbents and catalytic support. Researchers have recently become interested in their effectiveness in catalytic oxidation, hydrogenation, and acid-base aqueous processes [19]. Na-mordenite, a porous aluminosilicate zeolite, exhibits negative charge, chemical and thermal stability, large surface area, and substantial pore volume [20]. The iron concentration of the zeolites is thought to be responsible for the catalytic effectiveness of both natural and manufactured zeolite blends of mordenite and clinoptilolite in breaking down caffeine in aqueous media. Researchers have examined zeolite-semiconductor hybrids or nanocomposites as supports for semiconductor compositions to enhance photocatalytic performance [21]. Recent attempts focus on developing effective, low-cost treatment methods for large-scale applications to mitigate environmental impacts. Mass-producing solid hybrid photocatalyst composites is essential for large-scale industrial operations. Solid photocatalysts can come in direct contact with dye contaminants, improving degradation efficiency with minimal side reactions. It can be reused, withstand harsh conditions, and ensure long-term sustainability, making it ideal for commercial wastewater treatment applications [22].

The Box-Behnken design (BBD) is a real statistical technique for accelerating the optimization of dye degradation from industrial wastewater. One of its primary advantages is that it saves time and money by enabling fewer experiments to be conducted while still yielding a significant amount of reliable data. This design explores the complex relationships between several elements, offering insights into the main drivers of the degradation process. Its capacity to fit a quadratic model helps identify the most effective settings by capturing the minute details of how different variables affect dye removal [23,24]. Moreover, its robustness in the face of changes in experimental conditions ensures consistent and dependable results across different scenarios. By minimizing experimental errors, this method is instrumental in achieving precise and reproducible outcomes. Furthermore, by reducing the required number of trials, it effectively cuts down on costs and time, increasing the overall economy and efficacy of the optimization procedure. In conclusion, the BBD is an invaluable asset in enhancing the effectiveness and sustainability of industrial dye degradation.

This study uses a nanocomposite of mordenite zeolite loaded with TiO2 to study the photodegradation of acid red 57 dye (AR57D) in water treatment. This study evaluates several regulatory aspects, including photocatalytic degradation efficiency, catalyst dose, initial dye pollutant concentration, pH, contact time, and reusability. A Box-Behnken model was constructed using three components, and the optimal parameters for TiO2/NaMOR photodegradation of AR57 were determined using Response Surface Methodology (RSM).

2. Materials and Methods

2.1. Materials and catalyst characterization

Details for each material and instrument are included in Table S1 and S2 of the supplemental material.

Table S1

Table S2

2.2. Synthesis of TiO2/NaMOR photocatalyst

The TiO2/NaMOR nanocomposite was produced using a process involving wet impregnation and ignition at a temperature of 350°C. This procedure involved dissolving a certain quantity of titanium (IV) isopropoxide (0.25 g) and Na-mordenite (3.0 g) in 25 mL of methanol, followed by 15 mins of sonication. Following the combination of the two solutions, they were agitated for 6 h at room temperature to achieve homogeneity. Centrifugation was used to gather the resultant powder, which was then dried for 24 h at 70°C. Subsequently, the powder was ignited in an open crucible for 4 h, gradually raising the temperature from 25 to 350°C, followed by a gentle cooling process. The sample was stored in a polypropylene bottle for use (Figure 1).

Schematic diagram for the preparation of the photocatalyst (TiO2/NaMOR).
Figure 1.
Schematic diagram for the preparation of the photocatalyst (TiO2/NaMOR).

2.3. Photocatalytic dye degradation experiments

The organized TiO2/NaMOR photocatalyst’s capacity to break down Acid Red 57 (AR57) in aqueous solutions was assessed using a UV light in unconventional conditions. The UV lamp used in the research was a Philips model with specifications of Ephoton (eV) 3.10–3.94 and λmax (nm) 400-315 [25]. A 1.0 g/L stock solution of AR57 dye was utilized and could be diluted as needed with deionized water. A 150 mL beaker with a 5 cm internal width was employed as a reactor for the dye degradation investigations. The lamp was positioned 10 cm overhead the solution superficial in the reactor, which had a working volume of 100 mL containing the dye solution and photocatalyst powder. The TiO2/NaMOR (3.0 g/L) photocatalyst tasters were added to 100 mL of AR57 (30.0 mg/L) dye solution that had a pH of 5. Real stirring was necessary to guarantee the photocatalyst’s uniform distribution and avoid agglomeration. Before being exposed to UV light, the mixture was agitated for 30 mins at 600 rpm to achieve adsorption-desorption equilibrium and remove the influence of surface adsorption on the degradation of AR57 dye. The dye solution was exposed to UV light for 120 mins after reaching equilibrium. To extract the photocatalysts, samples of the solution were taken out of the photoreactor every five mins and centrifuged at 10,000 rpm.

The solid additive technique was used to find the point of zero charge (pHPZC) [26]. The influence of the original solution’s pH was assessed within the range of pH 2 to 10 (adjusted using 0.1 M HCl and NaOH). The dosage of the catalyst ranged from 1.0 to 6.0 g/L, with the concentration of AR57 dye held constant at 30 mg/L. Additionally, the effect of changing the concentration of AR57 dye (ranging from 10 to 60 mg/L) was examined using 3.0 g/L of TiO2/NaMOR photocatalyst for 90 mins of irradiation. After the individual sample was collected at specific time intervals, it was promptly centrifuged at 10,000 rpm for 5 mins to eliminate any suspended solid photocatalyst subdivisions for examination. To keep the enclosure at a consistent temperature, a ventilation fan is required. Finally, a UV-visible spectrophotometer was used to quantify the absorbance of AR57 dye within the supernatant liquid at the dye’s maximum absorption wavelength (λmax = 512 nm).

Eq. (1) was utilized to determine the dye’s degradation rate (D):

(1)
%   D= ( C 0 − C t ) C 0   × 100

Beer-Lambert’s law can be used to understand the relationship between A0, which represents the starting absorbance of the AR57 dye solution (blank), and At, which indicates its absorbance after t mins of irradiation or reaction. It claims that the concentrations of the sample and blank at time (t), C0 and Ct, are directly correlated with A0 and At [27]. The degradation of AR57 under photo conditions adheres to the pseudo-first-order kinetics as outlined by the Langmuir-Hinshelwood model [28]. As such, the rate of degradation of AR57 dye was examined by means of Eq. (2). The plot represents the linear relationship among ln (Ct/C0) and (t) for the specified experimental parameters, enabling the calculation of the photodegradation rate constant (k, min−1).

(2)
ln ⁡ ( C t ) C 0 = kt

The active species responsible for AR57 dye’s photocatalytic degradation, including electrons (e−), holes (h+), hydroxyl radicals (•OH), and superoxide anion radicals (•O2−), were studied using 0.001 M concentrations of various free radical scavengers such as AgNO3, KI, K2Cr2O7, and isopropanol. These experiments were carried out under UV light exposure with the same parameters. The hydroxyl radical was ultimately identified using the fluorescence method with terephthalic acid.

2.4. Experimental design

RSM is a useful technique for selecting the right variables for optimization. The first and second order constants are calculated using a particular type of RSM known as the BBD, which is based on three-level incomplete factorial approaches. To determine the response’s ideal adsorption capacity, this study evaluated the time, pH, dosage, and four other independent characteristics using three testing stages: -1, zero, and +1 (Table S3) [29].

Table S3

3. Results and Discussion

3.1. Characterization of TiO2/NaMOR

3.1.1. Powered X-ray diffraction (XRD) patterns

The X-ray diffraction patterns of the TiO2/NaMOR nanocomposite have been illustrated in Figure 2(a). Previous studies have confirmed that TiO2 with hierarchical porosity exhibits the characteristic peaks associated with the anatase phase [30]. In the composite, peaks were observed for both TiO2 and NaMOR. The diffractograms suggest that the composite contains a larger proportion of Na-Mordenite and a smaller proportion of TiO2.

(a) PXRD patterns of the synthesized TiO2/NaMOR, (b) The optical band gap energy resolve of TiO2/NaMOR nanostructure by means of Tauc’s model for n=2, (c) FTIR spectra of the synthesized TiO2/NaMOR and AR57@TiO2/NaMOR, (d) N2 Adsorption/desorption isotherm for TiO2/NaMOR nanocomposite, (e) Pore radius distribution, and (f) SEM and EDX of NaMOR.
Figure 2.
(a) PXRD patterns of the synthesized TiO2/NaMOR, (b) The optical band gap energy resolve of TiO2/NaMOR nanostructure by means of Tauc’s model for n=2, (c) FTIR spectra of the synthesized TiO2/NaMOR and AR57@TiO2/NaMOR, (d) N2 Adsorption/desorption isotherm for TiO2/NaMOR nanocomposite, (e) Pore radius distribution, and (f) SEM and EDX of NaMOR.

Powder X-ray diffraction (PXRD) was used for the analysis of NaMOR to determine its correct structure, with the results matching well with previously published literature [31]. The unit cell of Na-mordenite has sizes of a = 18.13 Å, b = 20.49 Å, and C = 7.52 Å, and can be chemically represented as [(Na2O)4.(A12O3)4.(SiO2)40.24H2O]. The diffraction pattern Figure 2(a) showed, peaks at 2θ = 13.45°, 19.61°, 22.20°, 25.63°, 26.25°, and 27.67° for Na-mordenite, corresponding to the planes (111), (330), (150), (202), (350), and (511), respectively (JCPDS card No. 06-062-1030). This suggests that the nano crystals of Na-mordenite exhibit preferential growth over random growth. The size of the ordered Na-mordenite nanoparticles was resolved to be about 25.5 nm using the Debye-Sherrer formula (Eq. 3) [32,33].

(3)
D = K λ β   c o s θ

The values of λ, β, θ, and K correspond to the X-ray wavelength (1.54 Å), the maximum of the Bragg diffraction peak, the angular width of the peak at half of its highest intensity (full-width at half-maximum) corrected for experimental broadening, and Scherrer’s constant (0.9 Å). The XRD patterns of the TiO2 nanostructures paired with NaMOR (TiO2/NaMOR) at 350°C can be seen in Figure 2(a). The diffraction peaks observed reveal well-crystallized TiO2, pointing to the creation of an anatase assembly (JCPDS No. 21-1272) by lattice constants a = b = 3.786 Å and c = 9.507 Å [34]. The peaks at 2θ = 25.34, 37.82, 38.10, 48.08, 53.94, 55.10, 62.78, 68.80, 70.59, and 75.2° are reflective of the (101), (103), (004), (200), (105), (211), (204), (116), (220), and (215) planes of TiO2, individually [35]. Using Eq. (4), the average size of the TiO2 nanoparticles’ crystallite size (D, Å) was found to be 13.5 nm from the major peak (2θ = 25.34°), which corresponds to the plane (101).

3.1.2. Optical band gap energy (Eg)

TiO2/NaMOR nanostructures’ energy band gap has been determined by employing UV-visible spectroscopy to analyze the optical characteristics of these particles. The band gap energy of semiconductors was calculated using Tauc’s formula [36], which shows the relationship among the absorption coefficient as expressed in Eq. (4).

(4)
( α h υ ) 1 / n = A ( h υ – E g )

The letter α represents the absorption coefficient, and h stands for Planck’s constant, while ʋ represents the frequency of vibration (ʋ= c/λ, where λ is the wavelength and c is the speed of light) [37]. Exponent n can have values of ½, 2, 3/2, and 3, corresponding to allow direct, allowed indirect, banned direct, and forbidden indirect transitions, respectively, depending on the kind of transition [38]. Often called the band-tailing parameter, A is a constant that is dependent on the transition probability. For homogeneous, amorphous semiconductors, n is always 2, independent of the kind of transition [39]. For TiO2/NaMOR, n = 2 is commonly used. The band gap energy was then determined graphically from (αhʋ)2 vs. E (Figure 2b). Utilizing Eq. (4) to extrapolate the linear portion on the abscissa, 3.295 eV was determined to be the band gap energy [40].

3.1.3. FTIR analysis

To ascertain the purity and characteristics of the TiO2/NaMOR nanostructure (Figure 2c), infrared studies were conducted. The lesser peak at around 3445 cm−1 is indicative of the stretching vibration of O–H in adsorbed water, whereas the peaks at 1739 cm−1 indicate the bending vibration of Ti–OH [41]. Additionally, the surfaces of the catalyst were found to adsorb atmospheric CO2, which is evident from the fewer penetrating peaks at 1369 and 2970 cm−1 [42]. Because of interatomic vibrations, metal oxides usually show absorption bands in the fingerprint region, i.e. below 1000 cm−1. The stretching vibration of Ti–O–Ti is associated with the absorption peak at 522 cm−1 [43].

3.1.4. N2 Adsorption/desorption isotherm

The findings from the Brunauer-Emmett-T (BET) analysis were subsequently used to analyze the N2 adsorption-desorption isotherms, as depicted in Figure 2(d). The information indicates that the N2 isotherm corresponds to type II through a high adsorption capability, yet reveals a wider distribution of pore sizes, thinner mesopores, and broader micropores, according to the IUPAC classification of adsorption isotherms [44,45]. The minimal hysteresis of the N2 adsorption-desorption isotherm suggests capillary compression and the mesoporous nature of the material. The surface area of the TiO2/NaMOR nanostructure is 46.73 m2/g, with an average pore size of 4.56 nm, total pore volume of 0.106 cm3/g, and a normal pore radius of 4.07 nm (Figure 2e).

3.1.5. SEM and EDX Analysis

Figure 2(f) represents SEM (Scanning Electron Microscopy) mapping accompanied by EDX (Energy Dispersive X-ray Spectroscopy) analysis of a material, likely sodium Mordenite (NaMOR). Central to the image is a high-resolution SEM depiction that captures large crystalline structures, with particle dimensions ranging from 24.73 to 196.1 nm. Encompassing the SEM image are color-coded elemental maps that delineate the spatial distribution of specific elements within the sample: oxygen (O) is represented in orange, sodium (Na) in green, aluminum (Al) in cyan, and silicon (Si) in purple. Positioned beneath these maps, the EDX spectrum illustrates the intensity of X-ray peaks, confirming the presence of the aforementioned elements. Additionally, a pie chart illustrates the elemental composition, indicating that oxygen constitutes 55.3%, silicon 29%, aluminum 6.7%, and sodium 9% of the sample. Each image contains a scale bar of 1 mm for reference, assisting in the visualization of the dimensions of the mapped regions and the intricate details of elemental distribution. This analysis provides a thorough examination of the material’s structure and compositional characteristics at a microscopic scale.

Figure 2(g) represents the SEM and EDX analysis of TiO2/NaMOR nanocomposite. The central SEM image provides high-resolution microscopy of the crystalline structures, demonstrating particle sizes ranging from 31.23 to 58.27 nm, with a scale bar of 500 nanometers for reference. Surrounding the SEM image are color-coded elemental maps that illustrate the spatial distribution of various elements: oxygen (O) is represented in orange, sodium (Na) in green, aluminum (Al) in cyan, silicon (Si) in purple, and titanium (Ti) in blue. The EDX spectrum and pie chart situated below the elemental maps indicate the composition of the material, disclosing that oxygen constitutes 46.2%, silicon 37.4%, sodium 8.1%, titanium 7.6%, and aluminum 0.8%. The spectrum further illustrates the intensity of the X-ray peaks corresponding to these elements. Each image is accompanied by a 1 mm scale bar for reference, which assists in visualizing the size and distribution of the elements present in the composite material. This analysis provides significant insights into the structural and compositional attributes of the TiO2/NaMOR nanocomposite [46,47].

(g) SEM and EDX of TiO2/NaMOR nanocomposite.
Figure 2.
(g) SEM and EDX of TiO2/NaMOR nanocomposite.

3.1.6. X-ray photoelectron spectroscopy (XPS)

To investigate the detailed information regarding the functional groups of TiO2/NaMOR and their element composition, XPS analysis was performed. Figure 3 shows five typical peaks at 1072, 532.5, 458.5, 103.5, and 74.5 eV, which were attributed to Na, O, Ti, Si, and Al, respectively [48-50].

TiO2/NaMOR review spectra by XPS. (a) Survey, (b) Na1s, (c) O1s, (d) Ti2p, (e) Si2p and (f) Al2p.
Figure 3.
TiO2/NaMOR review spectra by XPS. (a) Survey, (b) Na1s, (c) O1s, (d) Ti2p, (e) Si2p and (f) Al2p.

The XPS spectrum of Na1s displays a single prominent peak centered on 1072 eV, characteristic of sodium in a typical ionic state (Figure 3). This peak suggests that sodium is present in the composite material, most likely as part of the Na-mordenite structure.

The XPS spectrum of O1s features three distinct peaks that provide insights into the oxygen species present (Figure 3). The first peak, around 532.5 eV, is indicative of oxygen in hydroxyl groups (O-H) or adsorbed water molecules on the surface. The second peak, found at approximately 531 eV, corresponds to oxygen atoms in the Ti-O-Ti bonds, which are a part of the titanium dioxide lattice. The third peak, appearing near 529.5 eV, is associated with oxygen in metal-oxygen bonds.

The XPS spectrum of Ti2p shows seven distinct peaks, indicating various titanium chemical states and interactions within the material (Figure 3). The primary peaks at around 458.5 eV (Ti2p3/2) and 464.2 eV (Ti2p1/2) confirm titanium in the Ti4+ oxidation state, characteristic of TiO2, with a spin-orbit splitting of approximately 5.7 eV. A shoulder peak around 457 eV suggests the presence of Ti3+, indicating oxygen vacancies or defects that could enhance photocatalytic activity. An additional peak at 466 eV and smaller peaks around 460 eV and 463 eV may indicate titanium interactions with silicon from the mordenite, potentially forming Ti-O-Si linkages or surface complexes that modify the electronic structure. A broad peak around 468 eV hints at complex interactions, possibly involving multi-element interfaces.

The XPS spectrum of Si2p reveals two peaks that highlight different silicon environments within the material (Figure 3). The first peak, around 103.5 eV, corresponds to silicon atoms in the Si-O-Si configuration, typical of the mordenite framework, indicating that the silicon is part of the tetrahedrally coordinated structure essential for the integrity and stability of the zeolite. The second peak, around 102 eV, is slightly shifted to a lower binding energy, suggesting silicon in Si-O-Ti linkages, which indicates potential interactions between silicon, titanium, and oxygen.

The XPS spectrum of Al2p shows two distinct peaks that provide insights into the different chemical environments of aluminum within the material (Figure 3). The first peak, around 74.5 eV, is indicative of aluminum in an Al-O-Si environment, characteristic of the aluminum atoms within the mordenite framework. The second peak, at approximately 72.5 eV, suggests aluminum in a slightly different environment, possibly involving Al-O-Ti linkages, indicating interactions between aluminum and titanium.

3.1.7. Determining the point of zero charges (pHPZC)

The pH scale is a crucial factor in the degradation procedure of AR57, as it governs the ionized classes in the adsorbate solutions and the superficial charge of the photocatalyst [51,52]. The pHpzc for nanoparticles is the pH at which the particle’s surface has neither zeta potential nor a net charge. In the situation of TiO2/NaMOR, the pHpzc significance is approximately 7.5 (Figure 4a). This suggests that the protonation of active groups causes the TiO2/NaMOR surface to be negatively charged above this pHpzc and positively charged below it. Factors that influence this value include the composition of the substance, the presence of electrolytes, and the analytical instrument used.

(a) Relationship between TiO2/NaMOR nanocomposites’ starting pH and ∆pH, (b) Influence of pH on the properties of TiO2/NaMOR nanocomposite (90 mins irradiation time, 30 mg/L for AR57 dye concentration, 3.0 g/L dose of photocatalyst), (c) Influence of the initial concentration of AR57 dye on the photodegradation activity of TiO2/NaMOR nanocomposite (90 mins of irradiation time, 3.0 g/L TiO2/NaMOR nanocomposite, and pH = 5), (d) Influence of TiO2/NaMOR nanocomposite on the photodegradation activity of AR57 dye (30 mg/L) at 90 mins irradiation time and pH = 5, (e) Kinetic diagram for the AR57 dye photocatalytic degradation over TiO2/NaMOR nanocomposite exposed to UV light (30 mg/L dye concentration, 3.0 g/L catalyst amount and pH = 5).
Figure 4.
(a) Relationship between TiO2/NaMOR nanocomposites’ starting pH and ∆pH, (b) Influence of pH on the properties of TiO2/NaMOR nanocomposite (90 mins irradiation time, 30 mg/L for AR57 dye concentration, 3.0 g/L dose of photocatalyst), (c) Influence of the initial concentration of AR57 dye on the photodegradation activity of TiO2/NaMOR nanocomposite (90 mins of irradiation time, 3.0 g/L TiO2/NaMOR nanocomposite, and pH = 5), (d) Influence of TiO2/NaMOR nanocomposite on the photodegradation activity of AR57 dye (30 mg/L) at 90 mins irradiation time and pH = 5, (e) Kinetic diagram for the AR57 dye photocatalytic degradation over TiO2/NaMOR nanocomposite exposed to UV light (30 mg/L dye concentration, 3.0 g/L catalyst amount and pH = 5).

3.2. Photocatalytic degradation experiments

3.2.1. Influence of pH

The influence of pH changes (2.0 – 10.0) on the degradation of AR57 dye (30 mg/L) was examined with a 90 min exposure to light and a TiO2/NaMOR dosage of 3.0 g/L. The point of zero charge (pHpzc) is the pH at which the net charge of the entire particle surface equals zero and must be ascertained to evaluate how pH affects the degradation system’s efficacy. TiO2/NaMOR is claimed to have a pHpzc of 7.5. When the pH is lower than pHpzc, the material’s surface is positively charged; when the pH is greater than pHpzc, the surface is negatively charged [53]. Since the AR57 dye is anionic, it absorbs more on the TiO2/NaMOR surface at pH values below 7.5. In this experiment, a pH of 5.0 produced the best degradation effectiveness. The dye’s clearance efficiencies have beem shown in Figure 4(b). The removal efficiency dramatically dropped as the pH rose [54].

3.2.2. Influence of dose

The catalyst shows a crucial character in the photocalytic procedure as absorbent responses occur solely on the surface of the photocatalyst. The impact of varying catalyst dosages (1.0 – 6.0 g/L) was examined at a constant original color concentration of 30 mg/L and pH of 5.0. The quantities of TiO2/NaMOR photocatalyst directly affect degradation performance. As illustrated in Figure 4(c), an increase in the TiO2/NaMOR amount improves photocatalytic activity. In particular, the UV light source helps to excite more electrons from the valence band to the conduction band. The optimal photocatalytic amount was found to be 3.0 g/L with a 90-min contact time. Nonetheless, the effectiveness of degradation decreased slightly when a higher catalyst amount (3.0 g/L) was used. This is explained by the increased quantity of catalyst particles leading to turbidity, which in turn hinders the penetration of photons through the solution [55,56]. The optimal pH and photocatalyst amount for TiO2/NaMOR were also determined distinctly under the same irradiation time.

3.2.3. Influence of AR57 dye concentration

The impact of the original concentration of AR57 dye on its breakdown has been assessed using varying dye concentrations ranging from 10 to 60 mg/L, while keeping the TiO2/NaMOR photocatalyst concentration at 3.0 g/L and a pH of 5.0 (Figure 4d). It was observed that the degradation efficacy of the TiO2/NaMOR taster initially increased for dye concentrations up to 30 mg/L, then decreased. Consequently, the degradation effectiveness of the dye could be enhanced by starting with a lower original concentration [57,58]. This could be attributed to the increased degradation of dye particles on the photocatalyst’s surface as the initial dye concentration increased. Additionally, the blocking of photons before reaching the photocatalyst’s surface led to a decrease in photon adsorption by the photocatalyst [4].

3.3. Degradation Kinetics

The rate of degradation of AR57 dye on TiO2/NaMOR (3.0 g/L) was measured under UV irradiation, as shown in Figure 4(e). The degradation rate (D) of the dye was determined by means of the Eq. (1). A model based on pseudo-first order kinetics was employed to establish the kinetic rate constant (k) value for the degradation procedure of AR57 dye on the TiO2/NaMOR nanocomposite, and these values are typically represented by means of Eq. (2). The photodegradation rate constant (k, min−1) was computed from the slope of the straight-line segment of the plot of ln (Ct/C0) vs. t based on the experimental parameters used [59,60]. The observed linear association among ln(Ct/C0) and reaction time t for AR57 dye demonstrates behavior consistent with pseudo-first-order kinetics, as illustrated in Figure 4(e) with a correlation coefficient (R2 = 0.989) and a rate constant of 0.005 min−1 [61].

3.4. Mechanism of photodegradation

In order to ascertain the role of reactive oxygen species in the degradation of AR57 by the TiO2/NaMOR nanocomposite under UV light exposure, various scavengers were employed. Specifically, AgNO3, KI, isopropanol, and K2Cr2O7 were used to trap electrons (e−), holes (h+), hydroxyl radicals (•OH), and superoxide ions (•O2−) in the bulk solutions [62,63]. The presence of these scavengers in the TiO2/NaMOR suspensions, as indicated in Figure 5(a), had an impact on the degradation of AR57, suggesting that all of the e−, h+, •OH, and •O2− participated to the dye degradation. The use of AgNO3, KI, K2Cr2O7, and isopropanol resulted in degradation percentages of 89, 84, 20, and 16, respectively. These findings from Figure 5(a) confirmed that •OH and •O2− were the principal reactive oxygen classes involved in the photocatalytic degradation of AR57.

(a) On the photocatalytic degradation of AR57 dye using TiO2/NaMOR nanocomposite, the impact of different scavengers, and (b) Photoluminescence spectra of TiO2/NaMOR nanocomposite after irradiation (30 mg/L original dye concentration, 3.0 g/L of TiO2/NaMOR nanocomposite, 5x10−5 M terephthalic acid and pH = 5).
Figure 5.
(a) On the photocatalytic degradation of AR57 dye using TiO2/NaMOR nanocomposite, the impact of different scavengers, and (b) Photoluminescence spectra of TiO2/NaMOR nanocomposite after irradiation (30 mg/L original dye concentration, 3.0 g/L of TiO2/NaMOR nanocomposite, 5x10−5 M terephthalic acid and pH = 5).

Considering the scavenging examinations, the degradation of AR57 using the TiO2/NaMOR catalyst can be outlined through the following sequence of events: Under UV-light, TiO2/NaMOR becomes excited and generates electron-hole pairs, causing photogenerated electrons to move from TiO2/NaMOR to the surface of TiO2 [64]. The oxygen adsorbed on the surface produces superoxide radicals, which capture a portion of the electrons generated by TiO2/NaMOR (•O2−) with potent oxidizing properties, and subsequently break down the pollutant in the wastewater, as illustrated in the reactions (Eqs. 5-10) below:

(5)
TiO 2 / NaMOR + h υ → TiO 2 ( h ( VB ) + ) + TiO 2 ( e ( CB ) − )

(6)
e ( CB ) − + O 2 → • O 2 −

(7)
O 2 − + H 2 O → HO 2 • + • OH

(8)
OH − + h ( VB ) + → • OH

(9)
OH + • O 2 − + AR57 → products  ( CO 2 and H 2 O )

In the interim, the combining of positive holes and electrons may occur, principal to a potential decrease in the photocatalytic effectiveness of the fabricated TiO2 nanocatalyst.

(10)
TiO 2 ( h ( VB ) + ) + TiO 2 ( e ( CB ) − ) → TiO 2

With a narrower band gap, titanium dioxide is made up of the 3d and O2p shells, which are used by the VB and CB edges. The Eqs. (11) and (12) can be used to calculate the valence and conduction band potentials, the band gap (Eg), and the energy of free electrons in a semiconductor [65,66].

(11)
E CB = X – E e – 0. 5 E g

(12)
E VB = E CB + E g

Whenever the corresponding potential energies (eV) of the valence band (EVB) and conduction band (ECB) are ECB and EVB. Based on the information you provided [67]. TiO2/NaMOR band gap energy (Eg) is computed to be 3.295 eV, while the semiconductor’s absolute electronegativity (X) is 5.81 eV, and the energy of free electrons in a conventional hydrogen electrode (Ee) is 4.5 eV. The calculated theoretical standards for ECB and EVB of TiO2/NaMOR are 0.42 and 2.20 eV, respectively. These energy stages surpass the standard redox potential, indicating that TiO2/NaMOR possesses suitable energy levels for producing •OH and •O2− radicals essential for the photodegradation process. Experimental findings reveal that the photodegradation of AR57 dye declined from an initial 91.75 to 89, 84, 20, and 16% with the addition of AgNO3, KI, K2Cr2O7, and isopropanol. This underscores hydroxyl and superoxide radicals as the primary reactive classes responsible for the degradation process, see Figure 5(a).

In photoluminescence research, terephthalic acid (TPA) is used as a probing compound to investigate the production of (•OH) free radicals. Figure 5(b) illustrates the prominent peak at 423 nm that progressively intensifies with longer irradiation times (20, 40, 60, 80, and 100 mins) for TiO2/NaMOR, indicating the presence of 2-hydroxy terephthalic acid with a distinct fluorescent peak. The presence of this dominant peak suggests the generation of a significant quantity of •OH radicals.

3.5. Reusability

The assessment of the recyclability of the TiO2/NaMOR nanocomposite’s photocatalytic activity is crucial for its practical application on an industrial scale. To assess the stability of the photocatalyst, three replicate reusing experiments were carried out to assess its efficiency in degrading the AR57 dye. The suspended photocatalyst nanomaterial was used for the subsequent round of degradation studies after each experiment was completed. It was then centrifuged, dried at 100°C, and cleaned with distilled water and ethanol. The degradation efficiency of AR57 was noted to have decreased from the original 91.75 to 90.9, 89.8, 88.5, 87.5, and 86.8% after five cycles of the TiO2/NaMOR nanocomposite Figure 6(a). These findings imply that under continuous UV irradiation, the investigated photocatalyst demonstrated notable stability during the recycling processes [68]. Additionally, analysis of the spent catalyst sample using XRD revealed no notable changes in the crystallinity of TiO2 or other cations due to leaching when compared to the fresh catalyst nanocomposite sample [69]. The regenerated TiO2/NaMOR nanocomposite particles were examined using XRD. As shown in Figure 6(b), this indicates that the crystalline assembly of the nanocomposite particles was successfully maintained, as none of the characteristic XRD peaks of the elements changed after five rounds of adsorption and desorption.

(a) Reuse potential of TiO2/NaMOR photocatalyst for the degradation of AR57 dye, and (b) TiO2/NaMOR and regenerated XRD pattern.
Figure 6.
(a) Reuse potential of TiO2/NaMOR photocatalyst for the degradation of AR57 dye, and (b) TiO2/NaMOR and regenerated XRD pattern.

3.6. Comparison to other adsorbents

The maximal sorption capabilities of the TiO2 composite are determined by comparing them with values found in the collected works in Table S4. Despite the difficulties in directly associating sorption presentation because of differences in testing settings, this comparison offers a broad evaluation of the material’s potential. TiO2 composites’ exceptional capabilities increase the likelihood of wastewater treatment, particularly through the degradation of contaminants in water streams.

Table S4

3.7. Response surface analysis and modelling of experimental design

3.7.1. BBD

A total of 17 experiments were designed to utilize the BBD, as outlined in Table 1. The study analyzed the independent process parameters and their respective and combined effects on the efficiency of AR57 degradation. The research was carried out using the BBD method [26]. A quadratic polynomial model was used to create the mathematical relationship between the response and the process variables. The mathematical portrayal of the observed associations among the tested factor and the resulting response is expressed in coded Eq. (13) and actual Eq. (14).

(13)
q e = 96.6 + 4.99653 * A + 7.59429 * B + − 5.73121 * C + 0.77705 * A B + − 2.91.7517 * A C + − 0.942825 * B C + − 22.1478 * A 2 + − 25.7761 * B 2 + − 21.0736 * C 2

Table 1. Investigation of variance for the fitted models.
Source Total squares Df Mean squares F-value P-value
Model 7605.00 9 845.00 50.45 < 0.0001 Significant
A-pH 62.61 1 62.61 3.74 0.0944
B-Dose 199.72 1 199.72 11.92 0.0106
C-Conc. 173.78 1 173.78 10.37 0.0146
AB 34.38 1 34.38 2.05 0.1951
AC 185.50 1 185.50 11.07 0.0126
BC 2.42 1 2.42 0.1442 0.7154
A2 1385.51 1 1385.51 82.71 < 0.0001
B2 2648.74 1 2648.74 158.13 < 0.0001
C2 2196.97 1 2196.97 131.16 < 0.0001
Residual 117.25 7 16.75
Lack of fit 117.25 3 39.08
Pure error 0.0000 4 0.0000
Cor total 7722.25 16

The equation in coded form can be utilized to forecast the response for specific stages of the factor. By convention, the factors’ high stages are coded as +1, while the low levels are coded as -1. The coded equation is valuable for determining the comparative influence of the factors through the comparison of their coefficients [29].

(14)
q e = − 6 0. 39 0 2 + 28 . 128 * Dose + 3 . 2 0 375 * Conc . + 15 . 7285 * pH + 0.0 124328 * Dose * Conc . &nbsp; − 0. 291 . 7517 * Dose * pH − 0.00 942825 * Conc . * pH − 3 . 54365 * Dose 2 − 0.0 412418 * Conc . 2 − 1 . 3171 * pH 2

The amount of each factor, the equation can predict the result with respect to the real factors. It is crucial to confirm that each factor’s levels are expressed in their original units. Since the intercept does not represent the center of the design space and the coefficients are changed to account for the units of each element, it is not appropriate to use this equation to determine the proportionate influence of each factor.

3.7.2. Effect of input variables

Figure S1(a) demonstrates the application of the perturbation plot to analyze the collective influence of three input factors on the efficiency of AR57 degradation. The highest level of AR57 removal efficiency is achieved through the interplay of three primary aspects. The correlation between the amounts of degradation used (variable A) is a key factor [51]. Generally, a substantial alteration in the initial concentration (referred to as variable B) indicates its effect on the efficiency of AR57 degradation. A noticeable change in the pH level (variable C) suggests that it has a high impact on the degradation of AR57.

Figure S1

3.7.3. Analysis of variance (ANOVA)

The experimental data on degradation efficiency was subjected to statistical analysis using ANOVA, with the results presented in Table 1. The ANOVA findings utilize p-values, sum of squares, and F-values to identify significant variables. The F-value of 5437.91 (with a p-value of 0.0010) for the AR57 dye model indicates its important value. Moreover, the strong correlation between actual and projected values is evident from the high coefficient determination (R2) value of 0.9977. The statistical analysis revealed that several model terms, specified in Table 1, have Prob > F < 0.0500 values, indicating their significance under the specified conditions. Model terms with p-values less than 0.0500, such as A, B, C, AB, AC, BC, A2, B2, and C2, are considered significant. On the other hand, factors with p-values higher than 0.05 are deemed unimportant and were accordingly removed to enhance the model’s accuracy [60]. Any remaining model can be verified, and the residual distribution’s characteristics explained using a graphical approach. Illustrated in Figure S1(b), the customary probability chart is a common method for assessing the distribution of residuals in the model. No deviations from the basic assumptions of the analysis are evident, as demonstrated by the usual probability scheme of the residuals. The plot clearly displays a clustering of points around a straight line. The flawless fit of the residuals to normal distributions provides support for the autonomy of the residuals and the soundness of the assumptions. The relationship between the predicted and observed values of the degradation percentage (%) of AR57 by TiO2/NaMOR nanocomposite (AR57) is depicted in Figure S1(c). The strong resemblance between the actual and predicted values along a linear trajectory confirms the model’s statistical soundness.

The plot provided by the BBD software depicts the correlation among Externally Studentized Residuals and predicted standards, a common method in regression analysis for detecting outliers and assessing model adequacy (Figure S1d, e). Predicted values are represented on the x-axis, while Externally Studentized Residuals, adjusted to consider each observation’s impact, are presented on the y-axis. Critical thresholds for identifying significant outliers are denoted by horizontal red lines at approximately 4.82 and -4.82, suggesting that data points beyond these lines may be outliers [60]. The squares on the graph signify individual data points, with those closer to the horizontal axis indicating a strong fit with the model, and those further away indicating discrepancies between predicted and actual values. A random distribution of points around the zero line indicates that the model’s assumptions are being met, while points outside the thresholds signal potential outliers that could impact the model’s accuracy. This visualization is useful for diagnosing issues such as non-linearity, heteroscedasticity, or the presence of influential outliers in the regression model. The Box-Cox plot is a useful tool for determining the most suitable method to transform data in order to align with the assumptions of various statistical models (Figure S1f). It aids in identifying a power transformation that can stabilize the variance and normalize the data, particularly when it is skewed or displays varying levels of variability.

3.7.4. Contour plot

Figure 7(a) depicts the three-dimensional interaction and contour plot showing the association among the photocatalyst dose of 3.0 g/L and a concentration of AR57 dye 30.0 mg/L. In Figure 7(b), the interaction between pH and photocatalyst dose is illustrated, with the optimum conditions identified as pH 5 and a photocatalyst amount of 3.0 g/L. Finally, in Figure 7(c), the interaction between pH and initial concentration of AR57 dye is shown, with the optimal conditions identified as pH 5 and a concentration of 30.0 mg/L.

(a-c) Both 2D and 3-D response surfaces.
Figure 7.
(a-c) Both 2D and 3-D response surfaces.

3.7.5. Optimization using the desirability functions

This method starts by converting each individual response into a desirability value (di), which ranges from 0 to 1. A desirability value of 1 indicates that the response meets the desired outcome. Conversely, several 0s indicate that the reaction is greater than the allowable threshold. The primary objective is to identify a point at which desirability is maximized [57]. Therefore, a desirability function is utilized to simultaneously optimize procedure variables (A: photocatalyst dosage, B: dye conc., and C: pH) to achieve the optimal performance level for the response (AR57 degradation %). The software’s numerical optimization revealed that the optimal degradation of AR57 was achieved with a TiO2/NaMOR amount of 3.0 g/L, a solution pH of 5, and a concentration of 30 mg/L (Figure S2a-c). Under these operating situations, the AR57 elimination rate was 91.75%, with a desirability value of 1. By doing repeated confirmation trials with the optimized settings, the prediction’s correctness was confirmed. Overall, there was a strong correlation between the data from numerical optimization utilizing desirability parameters and the results from the experimental information. This implies that the experimental conditions for AR57 adsorption by TiO2/NaMOR can be efficiently optimized by using the BBD model with desire functions. Consequently, in later research, the ideal experimental setup for AR57 degradation was used.

Figure S2

4. Conclusions

The study examined the photocatalytic characteristics of the TiO2/NaMOR nanocomposite by looking at the photodegradation of AR57 in water under UV light. The results have shown that the nanocomposite possesses an optical band gap energy of 3.295 eV and a meaningfully increased specific surface area of 46.73 m2/g. Upon examination, it has been determined that the most effective dose for the photocatalytic properties of the TiO2/NaMOR nanocomposite is 3.0 g/L, resulting in a maximum photocatalytic degradation efficiency of 91.75 percent. The treatment protocol involves maintaining a pH of 5, utilizing an AR57 dye concentration of 30 mg/L, and subjecting the system to UV exposure for 90 mins. Throughout the photodegradation process, it has been observed that the kinetics follow a pseudo-first-order model with a rate constant of 0.005 min−1, which is primarily driven by the photocatalytic activity of TiO2/NaMOR as well as the presence of hydroxyl (•OH) and superoxide (•O2−) radicals. Additionally, the TiO2/NaMOR nanocomposite has shown exceptional stability and recyclability, with just a little drop in efficiency across several reuse cycles. In summary, the nanocomposite has been effectively demonstrated to be a reliable photocatalyst for the degradation of AR57 dye in wastewater treatment. Another way to improve its performance is to use the BBD process.

Acknowledgment

The authors extend their appreciation to Umm Al-Qura University, Saudi Arabia for funding this research work through grant number: (25UQU4361180GSSR02).

CRediT authorship contribution statement

Nada Alkhathami, Razan M. Snari: Data curation, formal analysis, methodology, and software; Ibtisam Mousa, Reem Ghubayra: Investigation and writing – review & editing; Omaymah Alaysuy, Saham F. Ibarhiam: formal analysis, investigation, writing-original draft. Kamelah S. Alrashdie, Fathy Shaaban: Supervision and administration of research group.

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.

Declaration of Generative AI and AI-assisted technologies in the writing process

The authors confirm that there was no use of artificial intelligence (AI)-assisted technology for assisting in the writing or editing of the manuscript and no images were manipulated using AI.

Data availability

All relevant data are within the manuscript and available from the corresponding author upon request.

Supplementary data

Supplementary material to this article can be found online at https://dx.doi.org/10.25259/AJC_128_2025.

References

  1. , . Application of low-cost adsorbents for dye removal – A review. J Environ Manage. 2009;90:2313-2342. https://doi.org/10.1016/j.jenvman.2008.11.017
    [Google Scholar]
  2. , , , , , . Biosorption potential of Neurospora crassa cells for decolorization of Acid Red 57 (AR57) dye. Journal of Chemical Technology Biotechnology. 2006;81:1100-1106. https://doi.org/10.1002/jctb.1462
    [Google Scholar]
  3. , , , , , , . Preparation of CuO nanoparticles via organometallic chelate for the removal of acid red 57 from aqueous solutions. Desalination and Water Treatment. 2021;222:282-294. https://doi.org/10.5004/dwt.2021.27067
    [Google Scholar]
  4. , , , , . Ag-loaded BiFeO3/CuS heterostructured based composite: An efficient photocatalyst for removal of antibiotics and antibacterial activities. Environmental Science and Pollution Research International. 2024;31:5540-5554. https://doi.org/10.1007/s11356-023-31523-3
    [Google Scholar]
  5. , , , , , , . Recent advances of photocatalytic coupling technologies for wastewater treatment. Chinese Journal of Catalysis. 2023;54:88-136. https://doi.org/10.1016/s1872-2067(23)64536-x
    [Google Scholar]
  6. , , . Heterogeneous photocatalysis in environmental remediation. Developments in Chemical Engineering and Mineral Processing. 2000;8:505-550. https://doi.org/10.1002/apj.5500080507
    [Google Scholar]
  7. , , , , , . Recent advances in structural engineering of photocatalysts for environmental remediation. Environ Res. 2023;219:115084. https://doi.org/10.1016/j.envres.2022.115084
    [Google Scholar]
  8. , , , , , . Recent advances in the synthesis of hierarchically mesoporous TiO2 materials for energy and environmental applications. Natl Sci Rev. 2020;7:1702-1725. https://doi.org/10.1093/nsr/nwaa021
    [Google Scholar]
  9. , , , , , , , , . Co- and Ni-Doped TiO2 nanoparticles supported on zeolite Y with photocatalytic properties. Nanomaterials (Basel, Switzerland). 2023;13:2200. https://doi.org/10.3390/nano13152200
    [Google Scholar]
  10. , , , , . Proficient sonophotocatalytic degradation of organic pollutants using Co3O4/TiO2 nanocomposite immobilized on zeolite: Optimization, and artificial neural network modeling. Ultrason Sonochem. 2024;102:106740. https://doi.org/10.1016/j.ultsonch.2023.106740
    [Google Scholar]
  11. , , , , , , , , . Black titanium dioxide nanomaterials for photocatalytic removal of pollutants: A review. J Mater Sci Technol. 2022;112:239-262. https://doi.org/10.1016/j.jmst.2021.09.057
    [Google Scholar]
  12. , , , . Hollow mesoporous TiO2 microspheres for enhanced photocatalytic degradation of acetaminophen in water. Chemosphere. 2016;152:490-495. https://doi.org/10.1016/j.chemosphere.2016.03.017
    [Google Scholar]
  13. , , . Fabrication of mesoporous CuO/ZrO2 -MCM-41 nanocomposites for photocatalytic reduction of Cr(VI) Chem Eng J. 2017;316:1122-1135. https://doi.org/10.1016/j.cej.2016.11.080
    [Google Scholar]
  14. , , , , . Surface modification of TiO2 with polydopamine and its effect on photocatalytic degradation mechanism. Colloids and Surfaces A: Physicochemical and Engineering Aspects. 2019;570:199-209. https://doi.org/10.1016/j.colsurfa.2019.03.018
    [Google Scholar]
  15. , , , , , . Effect of thermal treatment on the photocatalytic behavior of TiO2 supported on zeolites. New Journal of Chemistry. 2018;42:12001-12007. https://doi.org/10.1039/C8NJ01737A
    [Google Scholar]
  16. , , , , , , , , . Synthesis of high crystalline TiO2 nanoparticles on a polymer membrane to degrade pollutants from water. Catalysts. 2018;8:376. https://doi.org/10.3390/catal8090376
    [Google Scholar]
  17. , , , , , , , . Application of zeolite based nanocomposites for wastewater remediation: Evaluating newer and environmentally benign approaches. Environ Res. 2023;231:116073. https://doi.org/10.1016/j.envres.2023.116073
    [Google Scholar]
  18. , , . Zeolites as acid/basic solid catalysts: Recent synthetic developments. Catalysts. 2019;9:248. https://doi.org/10.3390/catal9030248
    [Google Scholar]
  19. , , , , , . Recent advances in the synthesis and applications of mordenite zeolite – review. RSC Adv. 2021;11:250-267. https://doi.org/10.1039/d0ra09434j
    [Google Scholar]
  20. , , . Unpredicted photocatalytic activity of clinoptilolite–mordenite natural zeolite. RSC Adv. 2020;10:39251-39260. https://doi.org/10.1039/d0ra06421a
    [Google Scholar]
  21. , , , , , . A novel Zn-doped CHA zeolite coupled CDs for photocatalytic nitrogen fixation. Molecular Catalysis. 2023;549:113471. https://doi.org/10.1016/j.mcat.2023.113471
    [Google Scholar]
  22. , , , . Zeolites in wastewater treatment: A comprehensive review on scientometric analysis, adsorption mechanisms, and future prospects. Environ Res. 2024;260:119782. https://doi.org/10.1016/j.envres.2024.119782
    [Google Scholar]
  23. , . Enhancing methyl violet 2B pollutant removal from wastewater using Al-MOF encapsulated with poly (itaconic acid) grafted crosslinked chitosan composite sponge: Synthesis, characterization, DFT calculation, adsorption optimization via Box-Behnken Design. Int J Biol Macromol. 2024;276:133909. https://doi.org/10.1016/j.ijbiomac.2024.133909
    [Google Scholar]
  24. , , , , , , . Adsorption and effective removal of organophosphorus pesticides from aqueous solution via novel metal-organic framework: Adsorption isotherms, kinetics, and optimization via box-behnken design. J Mol Liq. 2023;384:122206. https://doi.org/10.1016/j.molliq.2023.122206
    [Google Scholar]
  25. , , , . Efficient photocatalytic degradation of Acid Red 57 using synthesized ZnO nanowires. Journal of the Chinese Chemical Society. 2019;66:89-98. https://doi.org/10.1002/jccs.201800092
    [Google Scholar]
  26. , , , . Effect of metal organic framework alginate aerogel composite sponge on adsorption of tartrazine from aqueous solutions: Adsorption models, thermodynamics and optimization via Box-Behnken design. J Mol Liq. 2024;399:124392. https://doi.org/10.1016/j.molliq.2024.124392
    [Google Scholar]
  27. , , . Enhancement of the photocatalytic activity of ZnO nanoparticles by silver doping for the degradation of AY99 contaminants. J Mol Struct. 2019;1191:76-84. https://doi.org/10.1016/j.molstruc.2019.04.064
    [Google Scholar]
  28. , , , . Degradation behavior of mixed and isolated aromatic ring containing VOCs: Langmuir-Hinshelwood kinetics, photodegradation, in-situ FTIR and DFT studies. Journal of Environmental Chemical Engineering. 2021;9:105069. https://doi.org/10.1016/j.jece.2021.105069
    [Google Scholar]
  29. , , , , . Synthesis and characterization of metal–organic frameworks based on thorium for the effective removal of 2,4-dichlorophenylacetic pesticide from water: Batch adsorption and Box-Behnken Design optimization, and evaluation of reusability. J Mol Liq. 2024;398:124252. https://doi.org/10.1016/j.molliq.2024.124252
    [Google Scholar]
  30. , , , , . Synthesis of TiO2 with hierarchical porosity for the photooxidation of propene. Molecules. 2017;22:2243. https://doi.org/10.3390/molecules22122243
    [Google Scholar]
  31. , , . High performance of carbon dioxide adsorption of mesoporous mordenite synthesized in the presence of N,N-dimethylaniline. Res Chem Intermed. 2017;43:7443-7456. https://doi.org/10.1007/s11164-017-3085-2
    [Google Scholar]
  32. . The scherrer formula for X-Ray particle size determination. Physical Review. 1939;56:978-982. https://doi.org/10.1103/physrev.56.978
    [Google Scholar]
  33. R. Shirley, The CRYSFIRE Systemfor Automatic Powder Indexing: User’s Manual, The Lattice Press, Guildford, Surrey GU2 7NL, England, 2000.
  34. , , , , , , , , . Synthesis of high crystalline TiO2 nanoparticles on a polymer membrane to degrade pollutants from water. Catalysts. 2018;8:376-391. https://doi.org/10.3390/catal8090376
    [Google Scholar]
  35. , , , . Photocatalytic degradation of organic dyes in the presence of nanostructured titanium dioxide. Journal of Molecular Structure. 2020;1200:127115. https://doi.org/10.1016/j.molstruc.2019.127115
    [Google Scholar]
  36. , , . Optical properties and electronic structure of amorphous germanium. Physica. Status Solidi B. 1966;15:627-637. https://doi.org/10.1002/pssb.19660150224
    [Google Scholar]
  37. , , , , , . The fundamental role and mechanism of reduced graphene oxide in rGO/Pt-TiO2 nanocomposite for high-performance photocatalytic water splitting. Applied Catalysis B: Environmental. 2017;207:335-346. https://doi.org/10.1016/j.apcatb.2017.02.031
    [Google Scholar]
  38. , , , , . Enhanced photo-Fenton degradation of tetracycline using TiO2-coated α-Fe2O3 core–shell heterojunction. Journal of Industrial and Engineering Chemistry. 2018;68:14-23. https://doi.org/10.1016/j.jiec.2018.07.024
    [Google Scholar]
  39. . Optical Process in Semiconducters. Journal of The Electrochemical Society. 1972;119 https://doi.org/10.1149/1.2404256
    [Google Scholar]
  40. , , , , , . Effects of annealing temperature and method on structural and optical properties of TiO2 films prepared by RF magnetron sputtering at room temperature. Applied Surface Science. 2007;253:3888-3892. https://doi.org/10.1016/j.apsusc.2006.08.019
    [Google Scholar]
  41. , , , , . Surface modification of TiO2 with polydopamine and its effect on photocatalytic degradation mechanism. Colloids and Surfaces A: Physicochemical and Engineering Aspects. 2019;570:199-209. https://doi.org/10.1016/j.colsurfa.2019.03.018
    [Google Scholar]
  42. , , , , . Visible-light photocatalytic activity of Fe and/or Ni doped ilmenite derived-titanium dioxide nanoparticles. J Nanosci Nanotechnol. 2019;19:3343-3355. https://doi.org/10.1166/jnn.2019.16123
    [Google Scholar]
  43. , , , , , , , , , . Fe and Ni co-doped TiO2 nanoparticles prepared by alcohol-thermal method: Application in hydrogen evolution by water splitting under visible light irradiation. Powder Technol. 2012;228:210-218. https://doi.org/10.1016/j.powtec.2012.05.018
    [Google Scholar]
  44. , , , . Photocatalytic dye degradation from Textile wastewater: A review. ACS Omega. 2024;9:21751-21767. https://doi.org/10.1021/acsomega.4c00887
    [Google Scholar]
  45. , , , . Photodegradation of aromatic pollutants in water over TiO2 supported on molecular sieves. Applied Catalysis B: Environmental. 2001;31:241-249. https://doi.org/10.1016/S0926-3373(00)00283-6
    [Google Scholar]
  46. , , , , . Ordered mesoporous TiO2: The effect of structure, residual template and metal doping on photocatalytic activity. Catalysts. 2023;13:895. https://doi.org/10.3390/catal13050895
    [Google Scholar]
  47. , , , , , , , . Influence of UV-A light modulation on phenol mineralization by TiO2 photocatalytic process coadjuvated with H2O2. Catalysts. 2024;14:544. https://doi.org/10.3390/catal14080544
    [Google Scholar]
  48. , , , , . Deactivation of TiO2 photocatalytic films loaded on aluminium: XPS and AFM analyses. Applied Surface Science. 2006;252:7532-7538. https://doi.org/10.1016/j.apsusc.2005.09.023
    [Google Scholar]
  49. , , , , , , , . Photocatalytic degradation by TiO2-conjugated/coordination polymer heterojunction: Preparation, mechanisms, and prospects. Applied Catalysis B: Environment and Energy. 2024;344:123605. https://doi.org/10.1016/j.apcatb.2023.123605
    [Google Scholar]
  50. , . Photocatalytic dyes degradation on suspended and cement paste immobilized TiO2/g-C3N4 under simulated solar light. Journal of Environmental Chemical Engineering. 2021;9:105488. https://doi.org/10.1016/j.jece.2021.105488
    [Google Scholar]
  51. , , , , , , . Efficient adsorption of fluorescein dye from aqueous solutions by Al/Th-MOF bimetal-organic frameworks: Adsorption isotherm, kinetics, DFT computation, and optimization via Box-Behnken design. Process Safety and Environmental Protection. 2024;190:353-371. https://doi.org/10.1016/j.psep.2024.08.037
    [Google Scholar]
  52. , , , , , , , . A critical review of clay mineral-based photocatalysts for wastewater treatment. Catalysts. 2024;14:575. https://doi.org/10.3390/catal14090575
    [Google Scholar]
  53. , , , . Synthesis and photoelectrocatalytic applications of TiO2/ZnO/Diatomite composites. Catalysts. 2022;12:268. https://doi.org/10.3390/catal12030268
    [Google Scholar]
  54. , , , . Impact of CdS/SnO2 heterostructured nanoparticle as visible light active photocatalyst for the removal methylene blue dye. Journal of Photochemistry and Photobiology A: Chemistry. 2020;392:112403. https://doi.org/10.1016/j.jphotochem.2020.112403
    [Google Scholar]
  55. , , , . Magnetic chitosan grafted with polymerized thiourea for remazol brilliant blue R recovery: Effects of uptake conditions. Journal of Dispersion Science and Technology. 2017;38:943-952. https://doi.org/10.1080/01932691.2016.1216436
    [Google Scholar]
  56. , , , . Photocatalytic degradation of rhodamine B and remazol red B dyes using TiO2 nanomaterial: Estimation of the effective operating parameters. Desalination and Water Treatment. 2021;233:319-330. https://doi.org/10.5004/dwt.2021.27519
    [Google Scholar]
  57. , , , , , , . Adsorption and effective removal of organophosphorus pesticides from aqueous solution via novel metal-organic framework: Adsorption isotherms, kinetics, and optimization via box-behnken design. Journal of Molecular Liquids. 2023;384:122206. https://doi.org/10.1016/j.molliq.2023.122206
    [Google Scholar]
  58. , , , , . Photocatalytic oxidation of organic dyes and pollutants in wastewater using different modified titanium dioxides: A comparative review. Journal of Industrial and Engineering Chemistry. 2015;26:1-36. https://doi.org/10.1016/j.jiec.2014.10.043
    [Google Scholar]
  59. , , , , . Photocatalytic reactors dedicated to the degradation of hazardous organic pollutants: Kinetics, mechanistic aspects, and design. A Review, Chemical Engineering Communications. 2016;203:1415-1431. https://doi.org/10.1080/00986445.2016.1202243
    [Google Scholar]
  60. , , , , , . Synthesis and characterization of a novel TiO2@chitosan/alginate nanocomposite sponge for highly efficient removal of As(V) ions from aqueous solutions: Adsorption isotherm, kinetics, experiment and adsorption mechanism optimization using Box-Behnken design. Int J Biol Macromol. 2024;275:133513. https://doi.org/10.1016/j.ijbiomac.2024.133513
    [Google Scholar]
  61. , , , . Trends in photocatalytic degradation of organic dye pollutants using nanoparticles. A Review, Inorganic Chemistry Communications. 2024;159:111613. https://doi.org/10.1016/j.inoche.2023.111613
    [Google Scholar]
  62. , , , , , , . Scavenger-supported photocatalytic evidence of an extended type I electronic structure of the TiO2@Fe2O3 interface. ACS Appl Mater Interfaces. 2022;14:38255-38269. https://doi.org/10.1021/acsami.2c06404
    [Google Scholar]
  63. , , , , , , . Fabrication of CuO nanoparticle: An efficient catalyst utilized for sensing and degradation of phenol. Journal of Materials Research and Technology. 2020;9:11045-11059. https://doi.org/10.1016/j.jmrt.2020.07.100
    [Google Scholar]
  64. , , . Synthesis and characterization of TiO2 quantum dots for photocatalytic application. Journal of Saudi Chemical Society. 2015;19:589. https://doi.org/10.1016/j.jscs.2015.05.002
    [Google Scholar]
  65. , , , , . Fabrication and synergistically enhanced photocatalytic activity of ternary kaolinite, TiO2, and Al2O3 (K65T30A5) nanocomposite for visible-light-induced degradation of methylene blue and remazol red dye. Heliyon. 2024;10:e29255. https://doi.org/10.1016/j.heliyon.2024.e29255
    [Google Scholar]
  66. , , , , , , , . Optimization on the heterogeneous photocatalytic degradation of azorubine E122 dye using nanocomposite via CuO nanoparticles with sodium mordenite. Journal of Molecular Liquids. 2024;396:123926. https://doi.org/10.1016/j.molliq.2023.123926
    [Google Scholar]
  67. , , , , , . ZIF-8 supported Ag3PO4/g-C3N4 a Double Z-scheme heterojunction: An efficient photocatalytic, antibacterial and hemolytic nanomaterial. Journal of Water Process Engineering. 2024;65:105901. https://doi.org/10.1016/j.jwpe.2024.105901
    [Google Scholar]
  68. , , , , , , . Highly efficient adsorption and removal bio-staining dye from industrial wastewater onto mesoporous Ag-MOFs. Process Safety and Environmental Protection. 2023;172:395-407. https://doi.org/10.1016/j.psep.2023.02.036
    [Google Scholar]
  69. , , . Adsorption of industrial dye from aqueous solutions onto thermally treated green adsorbent: A complete batch system evaluation. Journal of Molecular Liquids. 2022;346:117082. https://doi.org/10.1016/j.molliq.2021.117082
    [Google Scholar]

Fulltext Views
1,505

PDF downloads
1,437
View/Download PDF
Download Citations
BibTeX
RIS
Show Sections

Suggested read for related articles: