Anchoring N-Halo (sodium dichloroisocyanurate) on the nano-Fe3O4 surface as “chlorine reservoir”: Antibacterial properties and wastewater treatment

Ardeshir Khazaei; Negin Sarmasti; Jaber Yousefi Seyf; Zohreh Merati

doi:10.1016/j.arabjc.2018.04.007

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Original article

13 (

); 2219-2232

doi:

10.1016/j.arabjc.2018.04.007

Anchoring N-Halo (sodium dichloroisocyanurate) on the nano-Fe₃O₄ surface as “chlorine reservoir”: Antibacterial properties and wastewater treatment

Ardeshir Khazaei^{^a,⁎}, Negin Sarmasti^{^a}, Jaber Yousefi Seyf^{^b}, Zohreh Merati^{^a}

a Faculty of Chemistry, Bu-Ali Sina University, Hamedan 6517838683, Iran

b Department of Chemical Engineering, Hamedan University of Technology, Hamedan, Iran

⁎Corresponding author. khazaei_1326@yahoo.com (Ardeshir Khazaei),

Received: 2017-12-26, Accepted: 2018-4-15, Published: 2018-01-01

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

A novel retrievable bifunctional magnetic nano-structure (sodium dichloroisocyanurate immobilized on the Fe₃O₄@SiO₂@Si(CH₂)₃Cl surface) was synthesized. Its antibacterial performance as water disinfectant successfully evaluated. The value of Minimum Bactericidal Concentration (625 ppm) and Minimum Inhibitory Concentration (314.5 ppm) show that magnetic nano-structure is a very effective antibacterial structure against the E. coli bacteria. In addition the viability of bacteria (%) was evaluated at different contact time against magnetic nano-structure. The disinfection procedure is very clean without any residual cyanuric acid in water. In other hand, oxidizing performance of nano-structure against the azo dye (acid red-18) was evaluated which attributed to the releasing HOCl in water. Kinetic of dye removal was measured at 0.01, 0.05, 0.1, and 0.5 g of nano-structure. Reducing pH and increasing temperature leads to increased Acid Red 18 degradation. Chemical oxygen demand (COD) measurement shows the effectiveness of nano-structure in acid red-18 degradation.

The nano-structure turns to be magnetically retrievable, clean disinfectant, wastewater treatment agent, and its chlorine can be regenerated simply by exposure to household bleach such as Ca(OCl)₂.

Keywords

Disinfection

Wast water treatment

Azo dye

Magnetic chlorine reservoir

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1 Introduction

Water can be studied from two points of views, namely, contaminated water with bacteria and wastewater containing azo dyes. Contaminated drinking water and inadequate water supplies for personal hygiene lead to estimated 4 billion cases of diarrhea and approximately 2 million deaths in developing areas and countries, mostly among young children under 5 years of ages. In developing countries, there are 4 main methods for household water treatments (HWT) which can be classified as a thermal, photolytic, chemical, or filtration methods (Smieja, 2011). Among them, chemical disinfection is one of the most effective, inexpensive treatments available (Clasen et al., 2007). With regard to this issue, chlorine has been used to disinfection of water, and its effectiveness has been widely evaluated (Disinfection, 2000). Chlorine can be available as calcium hypochlorite, sodium hypochlorite, lithium hypochlorite and chloroisocyanurates (sodium dichloroisocyanurate or trichloroisocyanuric acid). Although, NaOCl is the most common and accessible chemical for drinking water disinfectants, but it has a limited shelf life due to the HOCl decomposition upon heating or exposure to sunlight (Salter and Langhus, 2007). Unlike NaOCl which releases all of its chlorine, sodium dichloroisocyanurate (NaDCC) acts as “reservoir chlorine” because of chemical equilibrium, so that has been chiefly used for disinfection in swimming pools, industrial cooling towers, baby bottles and the contact lens (Quain, 2016). Finally, NaDCC has potential benefits over NaOCl, including microbiological effectiveness, compliance, acceptability and affordability (Clasen and Edmondson, 2006). Dissociation of NaDCC in water generates cyanuric acid, bring about the gradual rise its concentration in swimming pools. Excessive amounts of cyanuric acid uptake of free chlorine to drive the chemical equilibrium. Hence, excess amounts of cyanuric acid (>70 ppm) cause the chlorine to become progressively over-stabilized and interfere with its disinfection function (Teichberg, 2007). In addition, combination of residual cyanuric acid as by product with melamine can cause progressive tubular blockage, degeneration, and subsequent renal failure and death (Cianciolo et al., 2008; Reimschuessel et al., 2008).

With regard to this issue, researchers are interested to develop new and potent antibacterial materials, so that ozone (Biswas et al., 2003; Flyunt et al., 2003; Wenk et al., 2013 ), free halogen (Richardson, 2007; Wenk et al., 2013), chlorine oxide (Wenk et al., 2013), metal ions (Ran et al., 2011), quaternary ammonium salts (Song et al., 2011; Waschinski et al., 2008), quaternary phosphonium salts (Kenawy et al., 2002), molecularly engineered peptides (Shen et al., 2010), guanidine (Bromberg et al., 2010, 2011), N-chlorinated sulfonamides (Emerson, 1990), and N-halamines (Cao and Sun, 2009; Dong et al., 2015; Kang et al., 2015; Kocer et al., 2011; Ma et al., 2013 ) have been developed. Although, different magnetic and non-magnetic N-Halamine based nanoparticles have been synthesized for antibacterial purpose, but they have some drawbacks such as large particle size, high Minimum inhibitory concentration (MIC), high Minimum bactericidal concentration (MBC) and low chlorine content (Bai et al., 2016; Cao and Sun, 2009; Demir et al., 2015; Dong et al., 2011, 2013, 2017, 2010, 2015; Haham et al., 2016; Kang et al., 2015; Kocer et al., 2011; Li et al., 2015; Ma et al., 2013; Padmanabhuni et al., 2012 ). In other hand, Azo dyes constitute the main class of dyes used in industry (Zollinger and Iqbal, 2001), and more than 2000 azo dyes are known to exist (Nadupalli et al., 2011), so that more than half of commercial dyes are azo dyes. They broadly are used in the textile, color solvent, ink, paint, varnish, paper, plastic, food, pharmaceutics, and cosmetic industries. Precursor of some azo dyes, cleavage of azo double bond, reduction by intestinal anaerobic bacteria, and hepatic azo reductases may produce potentially toxic, carcinogenic, mutagenic and teratogenic compounds such as aromatic amines (Oxspring et al., 1996; “Predicting azo dye toxicity,” 1993). So, their release into environment through discharge from various industries, especially in water causes concern with water resources, soil fertility, aquatic organisms and ecosystem integrity and even socioeconomic and political dimensions (Dhale and Mahajani, 1999). With regard to this issue, and huge quantity of generated colored waste, several approaches have been developed for wastewater treatment which includes adsorption, flocculation, oxidation and electrolysis (“Anion Exchange Resins as Effective Sorbents for Acidic Dye Removal from Aqueous Solutions and Wastewaters,” 2012; Crini, 2003). Although adsorption turns to be uncomplicated, effective and economical technique (Shuang et al., 2012), but separation of pollutant (dye) and recovery is not practical (Wu et al., 2005).

In light the above discussion, a novel bifunctional magnetic nano-structure (antimicrobial and oxidizing agent) was synthesized by anchoring NaDCC on the nano-Fe₃O₄@SiO₂@Si(CH₂)₃Cl surface. It used as an antimicrobial magnetic nano-structure, with a low level of MIC and MBC, clean without any cyanuric acid residue, oxidizing of azo dyes by realizing HOCl, easily retrievable using a magnet, and regenerable to the initial structure with any chlorine source (bleach agent) such as NaOCl, and Ca(OCl)₂.

2 Materials and methods

2.1

2.1 Materials

Ferric chloride hexahydrate (FeCl₃·6H₂O), ammonia (28%), ferrous chloride tetrahydrate (FeCl₂·4H₂O), tetramethyl orthosilicate (TMOS), (3-Chloropropyl) triethoxysilane (CPS), sodium dichloroisocyanurate (NaDCC), acetone, toluene, ethanol, and ethyl acetate were obtained from Merck. The commercial azo dye, acid red 18 (AR18) was purchased from Alavan Sabet Company, Iran, and used without any purification.

2.2

2.2 Preparation and characterization of magnetic antimicrobial nano-structure

2.2.1

2.2.1 Synthesis magnetic Fe₃O₄

The magnetic (Fe₃O₄) nanoparticle was synthesized by coprecipitation method. First 11.3 gr FeCl₃·6H₂O and 5.6 gr FeCl₂·4H₂O were solved in deionized water at the 80 ^○C (600 rpm). After complete dissolution of the salts, 25 ml ammonia (28 wt%) was added immediately to the solution. The resulting black solution was vigorously stirred for 2 h at 80 ^○C temperature and N₂ atmosphere. Then the precipitated magnetic nanoparticles were separated from the solution using a magnet. Then it was washed several times with water and then with acetone, finally a stable black magnetic dispersion was obtained and dried in an oven.

2.2.2

2.2.2 Synthesis of nano-Fe₃O₄@SiO₂

As a result of anisotropic dipolar attraction, Fe₃O₄ nano-particles tend to aggregate, so that the silica coating through sol–gel process tackles this issue. To solve this issue, 1 g nano Fe₃O₄ (synthesized in the previous step) was dispersed in water and ethanol (80:20 v/v%) using ultrasound bath (15 min), then 2 ml ammonia (28 wt%) and 2 ml tetramethyl orthosilicate (TMOS) was added drop wise to the mixture and stirred at 50 ^○C for 2 h. The obtained Fe₃O₄@SiO₂ nanoparticles were separated using magnet and then washed with water, and ethanol, respectively, and dried in an oven.

2.2.3

2.2.3 Synthesis of nano-Fe₃O₄@SiO₂@Si(CH₂)₃Cl

1 g from the previous synthesized nanoparticles were dispersed in 50 ml toluene (15 min). Then 2 ml CPS was added gently to the mixture and then reflux at 110 ^○C for 24 h. Synthesized nanoparticles were separated using a magnet, washed several times with toluene, and water, respectively. The final product was dried in an oven.

2.2.4

2.2.4 Synthesis of nano-Fe₃O₄@SiO₂@Si(CH₂)₃@DCC

1.2 g of sodium dichloroisocyanurate (NaDCC) was dissolved in 50 ml dimethylformamide (DMF) and 1 g of the pervious synthesized nano-particles were added to the solution and dispersed using an ultrasonic bath (15 min). Then the mixture was reflux for 48 h, the product (Fe₃O₄@SiO₂@Si(CH₂)₃@DCC) was separated from solution using a magnet, then dispersed and stirred in 50 ml DMSO, separated using magnet and dried under vacuum. Chlorine groups on the surface of Fe₃O₄@SiO₂@Si(CH₂)₃Cl nanoparticles are so active that they can easily attach to sodium dichloroisocyanurate (NaDCC). Procedure for the synthesis of magnetic nano-structure (Fe₃O₄@SiO₂@Si(CH₂)₃@DCC) is shown in Fig. 1. Successful preparation was confirmed using different techniques, which includes FTIR, VSM, FESEM, TEM, EDX, XRD, and TGA.

Experimental recipe for the fabrication of magnetic antibacterial nano-structure (Fe3O4@SiO2@Si(CH2)3@DCC).

2.2.5

2.2.5 Characterization

FT-IR spectra of compounds were taken using a Perkin-Elmer Spectrum 65. Samples were well powdered and mixed with KBr to make the IR tablet. Vibrating sample magnetometer (VSM), model (MDKB), was used to determine the magnetic property. Field emission scanning electron microscopy (FESEM), Transmission electron microscopy (TEM) images were recorded with SIGMA VP-500 (ZEISS), Zeiss-EM10C-100 kV, respectively. Energy dispersive X-ray analysis (EDX) was also performed during the scanning electron microscope measurements for elemental analysis of a sample (Oxford Instrument). The X-rays diffraction (XRD) patterns were recorded with Apd2000 (Italstructures), equipped with a copper anode (λ = 1.5418 Å) producing X-rays, so that data were collected in continuous scan mode from 5 to 90 degrees (2θ) with a 0.1 sampling interval. Thermal gravimetric analysis (TGA) under a nitrogen atmosphere with 7 ^○C/min was used to determine changes in physical and chemical properties. To quantitative measurement of AR18 concentration, a UV/Visible spectrophotometer (JASCO V-630, Japan) was used. Chemical oxygen demand (COD) measurements were also carried out to investigate the mineralization of the solution, according to a close reflux, colorimetric method using a HACH DR 2800 as spectrophotometer and HACH DRB 200 as a heater.

2.3

2.3 Chlorine content and recharge ability (charge-discharge)

To determine the active chlorine content of Fe₃O₄@SiO₂@Si(CH₂)₃@DCC, iodometric titration was used (Badrossamay and Sun, 2009; Cao and Sun, 2009; Padmanabhuni et al., 2012 ). 0.05 g of the sample was added to a flask containing 40 ml CHCl₃ with 1.0 wt% acetic acid. Then, 1 g NaI was added, and the mixture stirred for 30 min at room temperature, under N₂ atmosphere. Magnetic nano particles were separated using a magnet, and the released iodine (I₂) was tittered with Na₂S₂O₃ 0.01 N. It should be noted that the chlorine in CHCl₃ is not active, so that CHCl₃ could not release Cl⁺ (the obtained carbanion (⁻CHCl₂) is not stable). The percentage of active chlorine was calculated based on the following reaction and expression: $N-Cl + 2 I^{-} + H^{+} \to N-H + I_{2} + {Cl}^{-}, I_{2} + 2 S_{2} O_{3}^{2 -} \to 2 I^{-} + S_{4} O_{6}^{2 -}$ $Cl (%) = \frac{35.5}{2} (\frac{V_{s} - V_{0}}{W_{s}}) C_{{Na}_{2} S_{2} O_{3}} \times 100$ where V_s, V₀, W_s, and $C_{{Na}_{2} S_{2} O_{3}}$ stand for consumed volume of Na₂S₂O₃ (ml) in Fe₃O₄@SiO₂@Si(CH₂)₃@DCC titration, consumed volume of Na₂S₂O₃ (ml) in Fe₃O₄@SiO₂ titration, weight of sample (mg), and the normality of Na₂S₂O₃, respectively.

To test the rechargeability of magnetic nano-structure, the Fe₃O₄@SiO₂@Si(CH₂)₃@DCC was first treated with a sodium thiosulfate (0.01 N) solution at room temperature to quench the active chlorine and then rechlorinated (4 g Ca(OCl)₂ was dissolved in 100 ml water, then the pH of solution adjusted to 7 with HCl 37 wt%. The Fe₃O₄@SiO₂@Si(CH₂)₃@DCC was added to the solution and stirred for 3 h, then separated with a magnet, washed multiple times with deionized water, and dried in an oven). Obtained magnetic nano-structure was tittered with Na₂S₂O₃ to re-evaluate the chlorine content. This procedure was repeated 5 times without chlorine content reduction.

2.4

2.4 Antibacterial test

The Escherichia coli (E. coli ATCC25922) as Gram-negative bacteria were used to evaluate the susceptibility of bacteria to magnetic nano-structure. The Minimal inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were used to determine the antibacterial activity of the sample. MBC and MIC were determined in a microwell plate (96 well) with the broth microdilution method. First 0.250 g magnetic nano-structure was dispersed in 100 ml water and stirred to release its hypochlorous acid (antibacterial moiety), then 200 μl from the dispersed solution was added to the first well of microwell plate, then 100 μl MuellerHinton Broth (MHB) was added to the next 11 wells, and serially diluted with the first well content, finally 100 μl diluted E. coli (incubated at 37 ^○C) was added to the all wells. In sequence, 100 μl of each well was dispersed onto MHB agar plates, and after incubation at 37 ^○C for 24 h, MIC and MBC were determined. MIC concentration was used to determine the biocidity.

For antibacterial test, in the first step a solution with MBC concentration were prepared and E. coli (0.5 McFarland standard = 1.5 × 10⁸ CFU/ml) added to it. In the second step, 10–20 μl from the prepared solution was added to the MHB agar plate, incubated at 37 ^○C, colonies on the plates were counted after incubation for 0, 10, 20, 30, 40, and 50 min.

2.5

2.5 Wastewater treatment

The anionic azo dye (acid red 18 (AR18)) was used as the model dye, so that its calibration curve was constructed using different AR18 concentration. To investigate the effect of magnetic nano-structure on the AR18 decomposition, an aqueous solution with 50 ppm were prepared, and then the magnetic nano-structure was added to the mixture and stirred rigorously. To determine the decomposed percent of AR18, samples were taken from the solution (the magnetic nano-structure was separated using a super magnet to the bottom of the vessel) at different times, and its concentration was identified using a UV/Visible spectrometer. Different masses of magnetic nano-structure was added the solution to investigate the effect of initial loading on the degradation of AR18. The experiments were carried out at isothermal condition (T = 298.15 K).

In another investigation, the effect of pH and temperature was studied, so that the pH was set with NaOH, and H₂SO₄ for alkaline, and acidic solutions, respectively. The temperature was set with a circulating water bath.

3 Results and discussion

The IR spectra of the nano-Fe₃O₄, nano-Fe₃O₄@SiO₂, nano-Fe₃O₄@SiO₂@Si(CH₂)₃Cl, nano-Fe₃O₄@SiO₂@Si(CH₂)₃@DCC (final product), and NaDCC are shown in Fig. 2. The wave numbers of 1100 cm⁻¹ stands for the Si-O of the SiO₂ in Fe₃O₄@SiO₂ MNPs, 2946.4 cm⁻¹ is related to the CH₂ group in Fe₃O₄@SiO₂@Si(CH₂)₃Cl, and 1710 and 1651 cm⁻¹ stand for carbonyl group in the Fe₃O₄@SiO₂@Si(CH₂)₃@DCC. In addition, the spectra part between 3300 and 3670 cm⁻¹ in NaDCC, and Fe₃O₄@SiO₂@Si(CH₂)₃@DCC are identical, which is shown with the dotted magenta eclipsed. These findings are evidence that the NaDCC has been loaded onto the Fe₃O₄@SiO₂@Si(CH₂)₃Cl surface.

FTIR spectra of (a) NaDCC, (b) Fe3O4@SiO2@Si(CH2)3@DCC, (c) Fe3O4@SiO2@Si(CH2)3Cl, (d) Fe3O4@SiO2, and (e) Fe3O4.

Pure NaDCC with human oral lethal dose (LD₅₀) 3570 mg/kg, which is classified as essentially nontoxic material (Milne and Wiley, 2005), can be used for disinfection, and for the purpose of biocidicity, but the cyanuric acid (CA) remains as a byproduct. Although CA is another low-toxic substance (LD₅₀ = 7700 mg/kg in rats), but when is present together with melamine, insoluble crystals form, which in turn leads to progressive tubular blockage, degeneration, and subsequent renal failure and death (Cianciolo et al., 2008; Dobson et al., 2008; Hard et al., 2009; Osborne et al., 2009; Reimschuessel et al., 2008; Ren et al., 2009 ). This is evidenced in contamination of animal feed in the United States in 2007 and the contamination of infant formula in China in 2008 (Ren et al., 2009). In the present study, to prevent CA residue in water from the usage of NaDCC as a disinfectant with antibacterial performance, a bi-functional nano-magnetic Fe₃O₄@SiO₂@Si(CH₂)₃@DCC was synthesized. This rational combination has some advantages which include antibacterial performance, and regenerability of magnetic antibacterial structure. The magnetic property of N-Halo nanoparticles were investigated by vibrating sample magnetometer (VSM). Fig. 3(a) shows the M-H curves of Fe₃O₄, Fe₃O₄@SiO₂, and Fe₃O₄@SiO₂@Si(CH₂)₃@DCC, so that the saturation magnetization are 55, 50, 29 emu/g for Fe₃O₄, Fe₃O₄@SiO₂, and Fe₃O₄@SiO₂@Si(CH₂)₃@DCC, respectively. Reduced magnetization in magnetic antimicrobial structure is attributed to the non-magnetic materials with the quenching of surface moments (Xu et al., 2007), and with increasing the thickness, the magnetization decreases. It should be noted that the magnetization in Fe₃O₄@SiO₂@Si(CH₂)₃@DCC with 3 layers is enough to easily separate the magnetic antibacterial structure. The macroscopic magnetic properties were examined within aqueous solution by placing a magnet near the glass bottle (Fig. 3(b)), so that antibacterial N-Halo immediately attracted to the magnet. This feature is so important, so that the magnetic antibacterial structure can be the local delivery onto bacterial colonies, easily separated, mechanically oriented, such as in water treatment system and cooling devices and pipes.

Magnetization curves of the Fe3O4, Fe3O4@SiO2, and Fe3O4@SiO2@Si(CH2)3@DCC MNPs.

The information about shape, size and morphology of the magnetic antibacterial structure are provided using FESEM and TEM which are given in Fig. 4. Based on FESEM results the shape of the nanoparticles is spherical and explicit core/shell structure is seen from TEM images that implies the coating of Fe₃O₄ nanoparticles.

(a) and (b) Field emission scanning electron microscopy (FESEM), (c) and (d) transmission electron microscopy (TEM) of the fabricated Fe3O4@SiO2@Si(CH2)3@DCC MNPs.

Plotted histogram of particle size data together with the fitted normal density function with these data is shown in Fig. 5. Left part of the histogram is truncated, which is related to the inability to measure the smaller particle size in FESEM image. The mean and the standard deviation of the nanoparticles are 25.20, and 7.32 (nm), respectively.

Histogram of values in data and fitted normal density function.

Further information about the composition of the magnetic antibacterial structure was provided with EDX which can be used to obtain an approximate elemental analysis. Fig. 6 shows the EDX analysis of Fe₃O₄@SiO₂@Si(CH₂)₃@DCC nano-structure. Mass percent are 36.0, 31.4, 18.7, 12.0, 1.1, and 0.8 for Fe, O, C, Si, N, and Cl, respectively. The Au peaks in Fig. 6 come from Au deposited on the tested sample before measurement.

The energy-dispersive X-ray spectroscopy (EDX) of Fe3O4@SiO2@Si(CH2)3@DCC MNPs.

To provide information about the phase, purity, crystallinity, nature, and size of magnetic antibacterial structure, XRD method is used. Scherrer’s equation (D = (Kλ)/(βcosθ)) is used to determine the size of nano-particles. The input parameters are K (dimensionless shape factor), λ (X-ray wavelength), β (full width at half maximum (FWHM) of the diffraction peak), and θ (Bragg diffraction angle in radian). Spherical crystalline shape is assumed in Scherrer analysis, so that 0.9, 0.154184 nm (averaged Cu K-Alpha) are used for K, and λ, respectively. Bragg equation (d_hkl = λ/2sinθ) was used to determine the d-spacing or interplaner spacing. Size of MNPs and d-spacing of the nanoparticles is given in Table 1. The mean value of nanoparticle size, and d-spacing are 12.57, and 2.1142 nm, respectively. The difference between the mean value of MNPs size using FESEM, and XRD techniques are related to inability to smaller particles, and approximated K value in FESEM, and XRD, respectively.

Table 1 X-ray diffraction (XRD) data for Fe₃O₄@SiO₂@Si(CH₂)₃@DCC MNPs.

Entry	2θ	Peak width [FWHM] (radian)	Size (nm)	Interplanar spacing of the crystal (nm)
1	30.50	0.841	9.45	2.9285
2	35.70	0.651	12.21	2.5130
3	43.60	0.740	10.74	2.0472
4	57.40	0.399	19.93	1.6040
5	62.80	0.756	10.52	1.4785
Mean			12.57	2.1142

XRD pattern of MNPs, namely, Fe₃O₄, Fe₃O₄@SiO₂, Fe₃O₄@SiO₂@Si(CH₂)₃Cl, and Fe₃O₄@SiO₂@Si(CH₂)₃@DCC are given in Fig. 7. As it is seen in Fig. 7, the coated layer does not change the crystallize mater of the Fe₃O₄.

XRD pattern of Fe3O4, Fe3O4@SiO2, Fe3O4@SiO2@Si(CH2)3Cl, and Fe3O4@SiO2@Si(CH2)3@DCC MNPs.

TGA and DTG techniques can be used to identify thermal decomposition, stability, and approximate number of the coated layers on the surface of a core, in a core/shell structure. Fig. 8, shows the TGA and DTG of the synthesized magnetic N-Halo structure. Region A up to 200 ^○C is attributed to the evaporation of organic solvents and water (3.5%),(Dong et al., 2011, 2010) region B stands for the loss of DCC from the magnetic nanostructure (2.5% up to 413 ^○C), loss of Si(CH₂)₃ is related to the region C (4.5% from 413 to 520 ^○C), and the incombustible residues remaining after pyrolysis (region D) are assumed to be the mixture of SiO₂, and Fe₃O₄ (Zhou et al., 2010).

Thermal gravimetric analysis (TGA) and derivative thermo-gravimetric (DTG) of Fe3O4@SiO2@Si(CH2)3@DCC.

Iodometric titration showed that the Fe₃O₄@SiO₂@Si(CH₂)₃@DCC has 6.18% active chlorine, suggesting that magnetic nano-structure coated with 19.52% DCC. The chlorine content is much higher than the most literature reported structures coated with N-Halamine, which include N‑Halamine epoxide based on cyanuric acid (0.1%) (Ma et al., 2013), N-Halamine-based antimicrobial fillers (1.18%) (Padmanabhuni et al., 2012), N-Halamine copolymers for use in antimicrobial paints (0.23–0.31%) (Kocer et al., 2011), barbituric acid-based magnetic N-Halamine nanoparticles (2.54%) (Dong et al., 2013), polymeric N-Halamine latex emulsions (5%) (Cao and Sun, 2009). The more chlorine content, the greater the bactericidal effect. The literature reported different N-halamine based antibacterial nanoparticles/particles together with their active chlorine content is given in the Table 2. The rechargeability test (5 times charge-discharge cycles) showed that the nano-structure keeps its original active chlorine value (6.18%), which confirms the conversion of the magnetic nano-structure to its active form.

Table 2 Chlorine content of different N-halamine based structures.

Entry	N-halamine based structure	Chlorine content (%)	Reference
1	Polymeric N-halamine latex emulsions	5	Cao and Sun (2009)
2	N-halamine copolymers for use in antimicrobial paints	0.23–0.31	Kocer et al. (2011)
3	N-halamine-based antimicrobial fillers	1.18	Padmanabhuni et al. (2012)
4	Cl-DMH-UA-CaCO3	1.18	Padmanabhuni et al. (2012)
5	N-halamine epoxide based on cyanuric acid	0.1	Ma et al. (2013)
6	Barbituric acid-based magnetic N-Halamine nanoparticles	2.54	Dong et al. (2013)
7	Polypropylene melt-blown nonwoven-1-chloro-2,2,5,5-tetramethyl-4-imidazolidinone	0.52	Demir et al. (2015)
8	Hydantoin loaded PMMA	0.61	Dong, et al. (2015)
9	Polyglycolide suture functionalized with N-halamines	0.75–0.31	Umair et al. (2015)
10	PMMA-DBDMH (1,3-dichloro-5,5-dimethylhydantoin)	16.26	Bai et al. (2016)
11	PMMA-DCDMH (1,3-dibromo-5,5-dimethylhydantoin)	5.01	Bai et al. (2016)
12	Antibacterial cellulose with N-halamine	0.2	Jiang et al. (2016)
13	Antimicrobial cotton fabrics treated with N-halamine	0.04–0.28	Liu et al. (2016)
14	Antibacterial mesoporous molecular sieves modified with polymeric N-halamine	2.39	Wang et al. (2016)
15	N-halamine modified thermoplastic polyurethane	1.79 μg/cm²	Qiao et al. (2017)
16	Antibacterial PVA containing TiO₂/N-halamine	57.83 μg/cm²	Ma et al. (2017)
17	Present study (Fe₃O₄@SiO₂@Si(CH₂)₃@DCC)	6.18	–

In addition, the potential of hydronium (pH) ion was used to confirm the loading of NaDCC on the Fe₃O₄@SiO₂@Si(CH₂)₃Cl surface, so that the pH of the 25 ml water from 6.31 decreases to the 5.32, immediately after adding 0.1 g magnetic nano-structure to the water. Decrease of pH is attributed to the dissociation of loaded DCC on the Fe₃O₄@SiO₂@Si(CH₂)₃Cl surface.

The antibacterial performance of the NaDCC immobilized on the Fe₃O₄@SiO₂@Si(CH₂)₃Cl was tested using Gram negative bacteria E. coli by broth microdilution method. In addition, the antibacterial assay of Fe₃O₄@SiO₂@Si(CH₂)₃Cl nanoparticle was used for comparison with control. No significant difference observed in antibacterial performance between control and Fe₃O₄@SiO₂@Si(CH₂)₃Cl, while the effect of Fe₃O₄@SiO₂@Si(CH₂)₃@DCC was considerable. These findings confirm that the antibacterial activity is attributed to the immobilized DCC. Oxidative chlorine transport from Fe₃O₄@SiO₂@Si(CH₂)₃@DCC to appropriate receptors in the cell membrane (Block, 2000). This chemical reaction can effectively destroy or inhibit enzymatic or metabolic cell processes, which in turn, leads to expiration of the microorganisms (Chen and Sun, 2006). Minimum bactericidal concentration (MBC) was defined as the sample concentration that kills all of the bacteria, and Minimum inhibitory concentration (MIC) was defined as the adjacent well with lower concentration. The MBC and MIC values are given in Table 3.

Table 3 Minimum Bactericidal Concentration (MBC) and Minimum Inhibitory Concentration (MIC) of the NaDCC-anchored on the Fe₃O₄@SiO₂@Si(CH₂)₃Cl against E. coli.

Bacteria	MBC (ppm)	MIC (ppm)
E. coli	625	314.5

Although to evaluate antibacterial performance, a higher concentration than MBC (seem to be quite high) have been used in the literatures, (Bromberg et al., 2010, 2011; Dong et al., 2011 ) but in the present work, MBC used to investigate the biocidity of Fe₃O₄@SiO₂@Si(CH₂)₃@DCC. The viability percent of the bacterial colonies at different contact time with the solution, obtained from NaDCC immobilized are given in Table 4 and Fig. 9.

Table 4 Viability percent of E. coli bacterial colonies at different contact time (at MBC concentration) after the exposure to Fe₃O₄@SiO₂@Si(CH₂)₃@DCC.

Time (min.)	Viability percent
0	4.13
10	3.58
20	2.78
30	1.76
40	0.66
50	0.0

Log CFU of E. coli bacterial colonies at different contact time (using MBC concentration), control (inoculum: 4.05 ± 0.29 log CFU per sample), Fe3O4@SiO2@Si(CH2)3Cl (inoculum: 4.1 ± 0.23 log CFU per sample), Fe3O4@SiO2@Si(CH2)3@DCC (inoculum: 4.13 ± 0.17 log CFU per sample).

The low values of MIC and MBC show that the antibacterial magnetic nano-structure is very effective to E. coli. These virulent strains of E. coli typically cause a bout of diarrhea that is often self-limiting in healthy adults, but is frequently lethal to children in the developing world (Nataro and Kaper, 1998). The reported value of MIC and MBC for N-Halamine-Immobilized PSA@Fe₃O₄@SiO₂ nanoparticles against P. aeruginosa are 60 and 80 mg/ml, which are very higher than our MIC and MBC. The bacterial activity can be affected by N-Halamine structure, chlorine content and particle size. The dissociation constant of various N-halamines in water, namely, imide, amide, and amine are <10⁻⁴, <10⁻⁹, and <10⁻¹², respectively. So, the bactericidal activity of N-halamine order is as: imide > amide > amine, so that hydantoins contain one imide and one amide group, while cyanuric acid contains three imide groups. Therefore, it is reasonable that hydantoins antibacterial activity is lower than cyanuric acids derivatives. In general, by increasing the amount of chlorine bactericidal power increases (Dong et al., 2017). The antimicrobial efficiency can be enhanced by reducing the particle size due to the increased surface area which leads to more activated surface sites that can kill the bacteria. Thanks to these overwhelming advantages, the as-synthesized antibacterial magnetic nano-structure with cyanuric acid structure, more chlorine content, and smaller particle size (12.57 nm versus 171 nm) is more promising antimicrobial agents than N-Halamine-Immobilized PSA@Fe₃O₄@SiO₂ and barbituric acid-based magnetic and non-magnetic N-Halamine nanoparticles (Dong et al., 2013, 2015). Table 5 shows the MBC, MIC, and percentage reduction of bacteria (%) of the present as-synthesized nano-structure together with literature reported antibacterial nanoparticles/particles/fibers. In most cases, the bacteria reduction percentage is 100%.

Table 5 MBC and MIC of different antibacterial nanoparticles/particles/fibers against E. coli and other bacteria.

Entry	Nanoparticles/particles/fibers	MBC (mg/ml)	MIC (mg/ml)	Reference
1	Present study (Fe₃O₄@SiO₂@Si(CH₂)₃@DCC)	0.625	0.314	–
2	SiO₂-PS-DMH	–	0.512	Dong et al. (2010)
3	PSA@Fe3O4@SiO2-DMH	80 (P. aeruginosa) >160 (S. aureus)	60 (P. aeruginosa) 80 (S. aureus)	Dong et al. (2011)
4	Barbituric acid based magnetic N-halamine nanoparticles (BAMNH NPs)	–	80	Dong et al. (2013)
5	Hydantoin based magnetic N-halamine nanoparticles (HMNH NPs)	–	160	Dong et al. (2013)

Entry	Nanoparticles/particles/fibers	Reduction (%)
1	Silica-quaternary ammonium	96.65% (E. coli)		Song et al. (2011)
2	N-halamine copolymers for use in antimicrobial paints	96.7 (S. aureus), 95.7 (E. coli)		Kocer et al. (2011)
3	Cl-DMH-UA	99.9 (S. aureus), 100 (E. coli)		Padmanabhuni et al. (2012)
4	Cl-DMH-UA-CaCO3	100 (S. aureus), 100 (E. coli)		Padmanabhuni et al. (2012)
5	N-halamine epoxide based on cyanuric acid	100 (S. aureus), 100 (E. coli)		Ma et al. (2013)
6	Polypropylene melt-blown nonwoven-1-chloro-2,2,5,5-tetramethyl-4-imidazolidinone	100 (S. aureus), 100 (E. coli)		Demir et al. (2015)
7	Halamine polymers fibers	100 (S. aureus), 100 (E. coli)		Kang et al. (2015)
8	IO/PMAA (iron oxide/cross-linked polymethacrylamide)	Partially effective (E. coli)		Haham et al. (2016)
9	PMMA-DBDMH (1,3-dichloro-5,5 dimethylhydantoin)	100 (S. aureus), 100 (E. coli)		Bai et al. (2016)
10	PMMA-DCDMH (1,3-dibromo-5,5-dimethylhydantoin)	100 (S. aureus), 100 (E. coli)		Bai et al. (2016)
11	Present study (Fe₃O₄@SiO₂@Si(CH₂)₃@DCC)	100 (E. coli)		–

In another investigation, the residual content of cyanuric acid in water was studied. Cyanuric acid or NaDCC forms a crystalline complex in the presence of melamine, which is shown in Fig. 10 (Perdigao et al., 2006). First, 0.1 g Fe₃O₄@SiO₂@Si(CH₂)₃@DCC was added to the 25 ml water, and stirred for 4 h, then the magnetic nano-structure was separated using a magnet. Finally, 0.05 g melamine was dissolved in 10 ml water and added to the solution and stirred for 5 min, so that a clear solution without any crystalline complex obtained which confirms the absence of cyanuric acid in the solution (Fig. 10).

(a) Solution of magnetic nano-structure in the presence of melamine (after separation of magnetic nano-structure), and (b) crystalline complex of NaDCC and melamine.

In wastewater treatment the percent removal of the AR18 was calculated using the following expression $Re moval (%) = (\frac{C_{0} - C}{C_{0}})$ where, C₀ and C stand for the initial and final concentrations of dye and COD in the synthetic wastewater (Basiri Parsa et al., 2013). The percent removal of AR18 using 0.01, 0.05, 0.1, and 0.5 g magnetic nano-structure is given in Fig. 11. Results show that by increasing the amount of catalyst, the removal of AR18 increases. After 24 h, the percent of removal are 43.7, 52.3, 60.18, and 84.9 for 0.01, 0.05, 0.1, and 0.5 g magnetic nano-structure, respectively. Increased time leads to remove the more color and after a while, no significant impact is seen. Results show that 0.1 g of magnetic nano-structure reduced the chemical oxygen demand (COD) up to 64.28% after 72 h.

Percent removal of AR18 using 0.01, 0.05, 0.1, and 0.5 g magnetic nano-structure.

In another investigation, the effect of pH on the AR18 degradation by the as-synthesized nano-structure was investigated at 25 °C. The amount of nano-structure and initial concentration of AR18 were 0.1, and 50 ppm, respectively. The results are given in Fig. 12, so that at the pH = 2, the maximum AR18 degradation achieved, and with increasing pH, the removal percentage of AR18 degradation decreases. This can be explained with equilibrium dissociation of HOCl in water (HOCl + H₂O ↔ OCl + H₃O⁺). According to Le Chatelier, at lower pH, the equilibrium shifts to the left side, so that the HOCl has a higher concentration than OCl⁻. The HOCl initiate the AR18 degradation reaction faster than OCl⁻ (Nadupalli et al., 2011). So, at a specified time and lower pH, the AR18 concentration will be lower than the higher pH, which is in consistence with the experimental results (Fig. 12). The HOCl is generated by dissociation of loaded DCC on the surface of the as synthesized magnetic nano-structure (Fig. 12).

The removal percentage of AR18 at different pH by the as-synthesized magnetic nano-structure.

To investigate the effect of temperature on the AR18 degradation using the as-synthesized magnetic nano-structure, the best pH (pH = 2) was used and the temperature was set at 25, 45, and 65 °C. The results are given in Fig. 13, so that with increasing temperature, the degradation of AR18 increases. This effect can be explained by the temperature effect on the reaction rate constant (Arrhenius equation) (Levenspiel, 1999).

The removal percentage of AR18 at different temperature (pH = 2) by the as-synthesized magnetic nano-structure.

To better represent the effect of three factors, namely, time, temperature, and pH, on the AR18 degradation, a quadratic model was fitted to the all experimental data (effect of pH and temperature). The obtained model is as follows:

(1)

Re moval (%) = 169.52 + 6.67 \times t - 1.15 \times T - 25.99 \times pH + 6.39 \times 10^{- 4} \times t \times T - 1.62 \times t \times pH + 7.78 \times 10^{- 2} \times T \times pH - 1.50 \times 10^{- 1} \times t^{2} + 1.94 \times 10^{- 3} \times T^{2} - 8.68 \times 10^{- 2} \times {pH}^{2}

The plus and minus symbols represent an increasing and decreasing effect, respectively. The value of each number represents the magnitude of its effect, so that the linear effect has the main role. Fig. 14 shows the effect of different parameters. Increasing the time increases the degradation of AR18 and ultimately leads to a flat area. Increasing the temperature and reducing the pH will increase the degradation.

The effect of time, temperature and pH on the removal percentage of AR18 by the as-synthesized magnetic nano-structure.

The plausible mechanism of AR18 using HOCl and OCl⁻ are shown in Fig. 15, which has been proved for AR27 by Nadupalli et al. (2011), so that the chemical structure of AR18 and AR27 is very similar. It has been shown that both OCl⁻ and HOCl initiate the reaction using first order path, while the latter reaction is faster.

Plausible mechanism for the chemical oxidation of AR18 using magnetic nano-structure.

The magnetic passive nano-structure (B in Fig. 15) not only could retrieve from the reaction media, but also it could be regenerated to the active nano-structure (A in Fig. 15) using NaOCl or Ca(OCl)₂. The discharge and charge procedure of the magnetic N-Halo nano-structure was repeated 5 times without loss of active chlorine content. This property makes the nano-structure used repeatedly without loss of activity. Chlorination treatment of 5,5-dimethylhydantoin (DMH) by NaOCl and convert it to N-halamine has been reported in the literature (Dong et al., 2011). Some of the various synthesized nanoparticles in the literature are given in Table 6, so that the most of them are non-magnetic nanoparticles and need to be separated from the reaction mixture by physical methods such as filtration. But, the as-synthesized nano-structure can be easily separated from the reaction mixture. In other hand, the present nano-structure can be charged with simple bleaching agents after loosing its catalytic activity, but the nanoparticles in Table 6 after disabling, must be discarded. The further details and comparison of catalysts for azo dye degradation can be found in the related review articles (Munoz et al., 2015).

Table 6 Nanoparticle used for degradation of azo dyes.

Entry	Nanoparticle	Dye	Reference
1	Present study (Fe₃O₄@SiO₂@Si(CH₂)₃@DCC)	Acid red 18	–
2	Palladium nanoparticles (PdNPs) + NaBH₄	p-Aminoazobenzene, Acid Red 66, Acid Orange 7, Scarlet 3G and reactive yellow 179	Li et al. (2017)
3	AuNPs/GC	Methylene blue	Khan et al. (2017)
4	Highly ordered TiO₂ nanotube arrays electrode	Methyl orange	Zhang et al. (2007)
5	Fe-Ni bimetallic nanoparticles	Orange G	Bokare et al. (2007)
6	SiO₂/TiO₂/CuBiS₂/Ag	Acid black 1	Abdullah and Kuo (2015)
7	ZnS-Ag-ZnO	Acid violet 7, acid black 1, active red 120, and reactive yellow 84	Subash et al. (2014)
8	Au/TiO₂	Orange II, ethyl orange, acid red G	Wang et al. (2008)
9	SnO₂/TiO₂	Naphthol blue black	Vinodgopal et al. (1996)
10	Magnetic Fe⁰/polyaniline nanofibers	Congo red	Das et al. (2017)
11	ZnO	Basic blue 41, basic red 46	Mahmoodi et al. (2017)
12	Fe₃O₄ magnetic nanoparticles	Rhodamine B	Chen et al. (2017)
13	Magnetic nanoscaled Fe3O4/CeO2	Orange G	Gan et al. (2017)
14	NiFe(C₂O)_x	Methyl orange	Liu et al. (2017)
15	Non-magnetic Pd-flyash and magnetic Pd-Fe₃O₄-flyash composite particles	Methylene blue	Narayani et al. (2017)
16	Co₂SiO₄	Methyl orange, acid brown, acid black	Bayat et al. (2016)
17	ZnO nanorods on Zn substrates	Congo red, methyl orange	Cai et al. (2014)

4 Conclusion

In this study, a new magnetic nano-structure was synthesized with a surface coating of Fe₃O₄@SiO₂@Si(CH₂)₃Cl with NaDCC. The antibacterial activity of Fe₃O₄@SiO₂@Si(CH₂)₃@DCC was evaluated against E. coli ATCC25922, and the values of MIC (314.5 ppm) and MBC (625 ppm) showed that Fe₃O₄@SiO₂@Si(CH₂)₃@DCC is a clean and an excellent disinfectant agent. Low values of MIC and MBC attributed to the small particle size (12.57 nm), higher chlorine content, and NaDCC structure. In addition, the wastewater treatment performance of the as-prepared magnetic nano-structure was tested successfully against AR18. The major advantages of the present study were that nano-structure is magnetic and can be separated easily, clean disinfectant, wastewater treatment agent, and can be regenerated to the active nano-structure using Ca(OCl)₂ which makes the nano-structure used repeatedly without loss of its activity. Therefore, the synthesized Fe₃O₄@SiO₂@Si(CH₂)₃@DCC in this study possess considerable potential for use in medical devices, healthcare products, water purification systems, hospitals, dental office equipment, food packaging, food storage, household sanitation, wastewater treatment systems, swimming pools, industrial cooling towers, baby bottles and contact lens, etc.

Acknowledgements

The authors gratefully acknowledge partial support of this work by the Research Affairs Office of Bu-Ali Sina University (Grant number 32-1716 entitled development of chemical methods, reagents and molecules), Center of Excellence in Development of Chemical Method (CEDCM), Hamedan, I. R. Iran.

References

Abdullah H., Kuo D.-H., . Photocatalytic performance of Ag and CuBiS2 nanoparticle-coated SiO2@TiO2 composite sphere under visible and ultraviolet light irradiation for azo dye degradation with the assistance of numerous nano p–n diodes. J. Phys. Chem. C. 2015;119:13632-13641.
[Google Scholar]
Anion Exchange Resins as Effective Sorbents for Acidic, . Dye removal from aqueous solutions and wastewaters. Solvent Extr. Ion Exch.. 2012;30:507-523.
[Google Scholar]
Badrossamay M.R., Sun G., . Graft polymerization of N-tert-butylacrylamide onto polypropylene during melt extrusion and biocidal properties of its products. Polym. Eng. Sci.. 2009;49:359-368.
[Google Scholar]
Bai R., Zhang Q., Li L., Li P., Wang Y.-J., Simalou O., Zhang Y., Gao G., Dong A., . N-halamine-containing electrospun fibers kill bacteria via a contact/release Co-determined antibacterial pathway. ACS Appl. Mater. Interfaces. 2016;8:31530-31540.
[Google Scholar]
Basiri Parsa J., Merati Z., Abbasi M., . Modeling and optimizing of electrochemical oxidation of C.I. Reactive Orange 7 on the Ti/Sb–SnO2 as anode via response surface methodology. J. Ind. Eng. Chem.. 2013;19:1350-1355.
[Google Scholar]
Bayat S., Ghanbari D., Salavati-Niasari M., . Pechini synthesis of Co2SiO4 magnetic nanoparticles and its application in photo-degradation of azo dyes. J. Mol. Liq.. 2016;220:223-231.
[Google Scholar]
Biswas K., Craik S., Smith D.W., Belosevic M., . Synergistic inactivation of Cryptosporidium parvum using ozone followed by free chlorine in natural water. Water Res.. 2003;37:4737-4747.
[Google Scholar]
Block S.S., . Disinfection, Sterilization, and Preservation. Philadelphia: Lea & Febiger; 2000.
Bokare A.D., Chikate R.C., Rode C.V., Paknikar K.M., . Effect of surface chemistry of Fe−Ni nanoparticles on mechanistic pathways of azo dye degradation. Environ. Sci. Technol.. 2007;41:7437-7443.
[Google Scholar]
Bromberg L., Chang E.P., Alvarez-Lorenzo C., Magariños B., Concheiro A., Hatton T.A., . Binding of functionalized paramagnetic nanoparticles to bacterial lipopolysaccharides and DNA. Langmuir. 2010;26:8829-8835.
[Google Scholar]
Bromberg L., Chang E.P., Hatton T.A., Concheiro A., Magariños B., Alvarez-Lorenzo C., . Bactericidal core-shell paramagnetic nanoparticles functionalized with poly(hexamethylene biguanide) Langmuir. 2011;27:420-429.
[Google Scholar]
Cai X., Han B., Deng S., Wang Y., Dong C., Wang Y., Djerdj I., . Hydrothermal growth of ZnO nanorods on Zn substrates and their application in degradation of azo dyes under ambient conditions. CrystEngComm. 2014;16:7761-7770.
[Google Scholar]
Cao Z., Sun Y., . Polymeric N-halamine latex emulsions for use in antimicrobial paints. ACS Appl. Mater. Interfaces. 2009;1:494-504.
[Google Scholar]
Chen F., Xie S., Huang X., Qiu X., . Ionothermal synthesis of Fe3O4 magnetic nanoparticles as efficient heterogeneous Fenton-like catalysts for degradation of organic pollutants with H2O2. J. Hazard. Mater.. 2017;322:152-162.
[Google Scholar]
Chen Z., Sun Y., . N-halamine-based antimicrobial additives for polymers: preparation, characterization, and antimicrobial activity. Ind. Eng. Chem. Res.. 2006;45:2634-2640.
[Google Scholar]
Cianciolo R.E., Bischoff K., Ebel J.G., Van Winkle T.J., Goldstein R.E., Serfilippi L.M., . Clinicopathologic, histologic, and toxicologic findings in 70 cats inadvertently exposed to pet food contaminated with melamine and cyanuric acid. J. Am. Vet. Med. Assoc.. 2008;233:729-737.
[Google Scholar]
Clasen T., Edmondson P., . Sodium dichloroisocyanurate (NaDCC) tablets as an alternative to sodium hypochlorite for the routine treatment of drinking water at the household level. Int. J. Hyg. Environ. Health. 2006;209:173-181.
[Google Scholar]
Clasen T., Haller L., Walker D., Bartram J., Cairncross S., . Cost-effectiveness of water quality interventions for preventing diarrhoeal disease in developing countries. J. Water Health. 2007;5:599-608.
[Google Scholar]
Crini G., . Studies on adsorption of dyes on beta-cyclodextrin polymer. Bioresour. Technol.. 2003;90:193-198.
[Google Scholar]
Das R., Bhaumik M., Giri S., Maity A., . Sonocatalytic rapid degradation of Congo red dye from aqueous solution using magnetic Fe0/polyaniline nanofibers. Ultrason. Sonochem.. 2017;37:600-613.
[Google Scholar]
Demir B., Cerkez I., Worley S.D., Broughton R.M., Huang T.-S., . N-halamine-modified antimicrobial polypropylene nonwoven fabrics for use against airborne bacteria. ACS Appl. Mater. Interfaces. 2015;7:1752-1757.
[Google Scholar]
Dhale A.D., Mahajani V.V., . Reactive dye house wastewater treatment. Use of hybrid technology: membrane, sonication followed by wet oxidation. Ind. Eng. Chem. Res.. 1999;38:2058-2064.
[Google Scholar]
Disinfection A.W.Q.D., . Committee report -disinfection at large and medium-size systems. J. Am. Water Works Assoc.. 2000;92:32-34.
[Google Scholar]
Dobson R.L.M., Motlagh S., Quijano M., Cambron R.T., Baker T.R., Pullen A.M., Regg B.T., Bigalow-Kern A.S., Vennard T., Fix A., Reimschuessel R., Overmann G., Shan Y., Daston G.P., . Identification and characterization of toxicity of contaminants in pet food leading to an outbreak of renal toxicity in cats and dogs. Toxicol. Sci.. 2008;106:251-262.
[Google Scholar]
Dong A., Lan S., Huang J., Wang T., Zhao T., Xiao L., Wang W., Zheng X., Liu F., Gao G., Chen Y., . Modifying Fe3O4-functionalized nanoparticles with N-halamine and their magnetic/antibacterial properties. ACS Appl. Mater. Interfaces. 2011;3:4228-4235.
[Google Scholar]
Dong A., Sun Y., Lan S., Wang Q., Cai Q., Qi X., Zhang Y., Gao G., Liu F., Harnoode C., . Barbituric acid-based magnetic N-halamine nanoparticles as recyclable antibacterial agents. ACS Appl. Mater. Interfaces. 2013;5:8125-8133.
[Google Scholar]
Dong A., Wang Y.-J., Gao Y., Gao T., Gao G., . Chemical insights into antibacterial N-halamines. Chem. Rev.. 2017;117:4806-4862.
[Google Scholar]
Dong A., Zhang Q., Wang T., Wang W., Liu F., Gao G., . Immobilization of cyclic N-halamine on polystyrene-functionalized silica nanoparticles: synthesis, characterization, and biocidal activity. J. Phys. Chem. C. 2010;114:17298-17303.
[Google Scholar]
Dong Q., Cai Q., Gao Y., Zhang S., Gao G., Harnoode C., Morigen, Dong A., . Synthesis and bactericidal evaluation of imide N-halamine-loaded PMMA nanoparticles. New J. Chem.. 2015;39:1783-1791.
[Google Scholar]
Emerson D.W., . Polymer-bound active chlorine: disinfection of water in a flow system. Polymer supported reagents. 5. Ind. Eng. Chem. Res.. 1990;29:448-450.
[Google Scholar]
Flyunt R., Leitzke A., Mark G., Mvula E., Reisz E., Schick R., von Sonntag C., . Determination of •OH, O2•-, and hydroperoxide yields in ozone reactions in aqueous solution. J. Phys. Chem. B. 2003;107:7242-7253.
[Google Scholar]
Gan G., Liu J., Zhu Z., Yang Z., Zhang C., Hou X., . A novel magnetic nanoscaled Fe3O4/CeO2 composite prepared by oxidation-precipitation process and its application for degradation of orange G in aqueous solution as Fenton-like heterogeneous catalyst. Chemosphere. 2017;168:254-263.
[Google Scholar]
Haham H., Natan M., Gutman O., Kolitz-Domb M., Banin E., Margel S., . Engineering of superparamagnetic core-shell iron oxide/N-chloramine nanoparticles for water purification. ACS Appl. Mater. Interfaces. 2016;8:18488-18495.
[Google Scholar]
Hard G.C., Flake G.P., Sills R.C., . Re-evaluation of kidney histopathology from 13-week toxicity and two-year carcinogenicity studies of melamine in the F344 rat: Morphologic evidence of retrograde nephropathy. Vet. Pathol.. 2009;46:1248-1257.
[Google Scholar]
Jiang Z., Liu Y., Li R., Ren X., Huang T.S., . Preparation of antibacterial cellulose with a monochloro-s-triazine-based N-halamine biocide. Polym. Adv. Technol.. 2016;27:460-465.
[Google Scholar]
Kang J., Han J., Gao Y., Gao T., Lan S., Xiao L., Zhang Y., Gao G., Chokto H., Dong A., . Unexpected enhancement in antibacterial activity of N-halamine polymers from spheres to fibers. ACS Appl. Mater. Interfaces. 2015;7:17516-17526.
[Google Scholar]
Kenawy E.-R., Abdel-Hay F.I., El-Shanshoury A.E.-R.R., El-Newehy M.H., . Biologically active polymers. V. Synthesis and antimicrobial activity of modified poly(glycidyl methacrylate-co-2-hydroxyethyl methacrylate) derivatives with quaternary ammonium and phosphonium salts. J. Polym. Sci., Part A: Polym. Chem.. 2002;40:2384-2393.
[Google Scholar]
Khan Z.U.H., Khan A., Chen Y., Khan A.u., Shah N.S., Muhammad N., Murtaza B., Tahir K., Khan F.U., Wan P., . Photo catalytic applications of gold nanoparticles synthesized by green route and electrochemical degradation of phenolic Azo dyes using AuNPs/GC as modified paste electrode. J. Alloy. Compd.. 2017;725:869-876.
[Google Scholar]
Kocer H.B., Cerkez I., Worley S.D., Broughton R.M., Huang T.S., . N-halamine copolymers for use in antimicrobial paints. ACS Appl. Mater. Interfaces. 2011;3:3189-3194.
[Google Scholar]
Levenspiel O., . Chemical Reaction Engineering. New York; Toronto: Wiley; 1999.
Li C., Hou J., Huang Z., Zhao T., Xiao L., Gao G., Harnoode C., Dong A., . Assessment of 2,2,6,6-tetramethyl-4-piperidinol-based amine N-halamine-labeled silica nanoparticles as potent antibiotics for deactivating bacteria. Colloids Surf. B Biointerfaces. 2015;126:106-114.
[Google Scholar]
Li G., Li Y., Wang Z., Liu H., . Green synthesis of palladium nanoparticles with carboxymethyl cellulose for degradation of azo-dyes. Mater. Chem. Phys.. 2017;187:133-140.
[Google Scholar]
Liu Y., He Q., Li R., Huang D., Ren X., Huang T.-S., . Durable antimicrobial cotton fabrics treated with a novel N-halamine compound. Fibers Polym.. 2016;17:2035-2040.
[Google Scholar]
Liu Y., Zhang G., Chong S., Zhang N., Chang H., Huang T., Fang S., . NiFe(C2O4)x as a heterogeneous Fenton catalyst for removal of methyl orange. J. Environ. Manage.. 2017;192:150-155.
[Google Scholar]
Ma K., Liu Y., Xie Z., Li R., Jiang Z., Ren X., Huang T.-S., . Synthesis of novel N-halamine epoxide based on cyanuric acid and its application for antimicrobial finishing. Ind. Eng. Chem. Res.. 2013;52:7413-7418.
[Google Scholar]
Ma W., Li L., Li J., Ren X., Gu Z.-G., Huang T.-S., . Antibacterial PVA membranes containing TiO2/N-halamine nanoparticles. Adv. Polym. Tech. 2017 n/a-n/a
[Google Scholar]
Mahmoodi N.M., Keshavarzi S., Ghezelbash M., . Synthesis of nanoparticle and modelling of its photocatalytic dye degradation ability from colored wastewater. J. Environ. Chem. Eng.. 2017;5:3684-3689.
[Google Scholar]
Milne, G.W.A., Wiley, I., 2005. Gardner's commercially important chemicals: synonyms, trade names, and properties. Hoboken, N.J.: Wiley-Interscience.
Munoz M., de Pedro Z.M., Casas J.A., Rodriguez J.J., . Preparation of magnetite-based catalysts and their application in heterogeneous Fenton oxidation – A review. Appl. Catal. B. 2015;176–177:249-265.
[Google Scholar]
Nadupalli S., Koorbanally N., Jonnalagadda S.B., . Kinetics and mechanism of the oxidation of amaranth with hypochlorite. J. Phys. Chem. A. 2011;115:7948-7954.
[Google Scholar]
Narayani H., Augustine R., Sumi S., Jose M., Deepa Nair K., Samsuddin M., Prakash H., Shukla S., . Removal of basic and industrial azo reactive dyes from aqueous solutions via Fenton-like reactions using catalytic non-magnetic Pd-flyash and magnetic Pd-Fe3O4-flyash composite particles. Sep. Purif. Technol.. 2017;172:338-349.
[Google Scholar]
Nataro J.P., Kaper J.B., . Diarrheagenic Escherichia coli. Clin. Microbiol. Rev.. 1998;11:142-201.
[Google Scholar]
Osborne C.A., Lulich J.P., Ulrich L.K., Koehler L.A., Albasan H., Sauer L., Schubert G., . Melamine and cyanuric acid-induced crystalluria, uroliths, and nephrotoxicity in dogs and cats. Veterinary Clinics of North America - Small Animal Practice. 2009;39:1-14.
[Google Scholar]
Oxspring D.A., McMullan G., Smyth W.F., Marchant R., . Decolourisation and metabolism of the reactive textile dye, Remazol Black B, by an immobilized microbial consortium. Biotechnol. Lett.. 1996;18:527-530.
[Google Scholar]
Padmanabhuni R.V., Luo J., Cao Z., Sun Y., . Preparation and characterization of N-halamine-based antimicrobial fillers. Ind. Eng. Chem. Res.. 2012;51:5148-5156.
[Google Scholar]
Perdigao L.M.A., Champness N.R., Beton P.H., . Surface self-assembly of the cyanuric acid-melamine hydrogen bonded network. Chem. Commun. 2006:538-540.
[Google Scholar]
Predicting azo dye toxicity, 1993. Critical Reviews in Environmental Science and Technology, 23, 249–324.
Qiao M., Ren T., Huang T.-S., Weese J., Liu Y., Ren X., Farag R., . N-Halamine modified thermoplastic polyurethane with rechargeable antimicrobial function for food contact surface. RSC Adv.. 2017;7:1233-1240.
[Google Scholar]
Quain D.E., . Draught beer hygiene: cleaning of dispense tap nozzles. J. Inst. Brew.. 2016;122:388-396.
[Google Scholar]
Ran X., Wang L., Cao D., Lin Y., Hao J., . Synthesis, characterization and in vitro biological activity of cobalt(II), copper(II) and zinc(II) Schiff base complexes derived from salicylaldehyde and D, L-selenomethionine. Appl. Organomet. Chem.. 2011;25:9-15.
[Google Scholar]
Reimschuessel R., Gieseker C.M., Miller R.A., Ward J., Boehmer J., Rummel N., Heller D.N., Nochetto C., de Alwis G.K.H., Bataller N., Andersen W.C., Turnipseed S.B., Karbiwnyk C.M., Satzger R.D., Crowe J.B., Wilber N.R., Reinhard M.K., Roberts J.F., Witkowski M.R., . Evaluation of the renal effects of experimental feeding of melamine and cyanuric acid to fish and pigs. Am. J. Vet. Res.. 2008;69:1217-1228.
[Google Scholar]
Ren F.Y., Wang Y., Hou X.B., Zhang C.R., Ling M., . Clinical and imaging features in 16 infants exposed to food contaminated with melamine and cyanuric acid. Am. J. Roentgenol.. 2009;192:707-710.
[Google Scholar]
Richardson S.D., . Water analysis: emerging contaminants and current issues. Anal. Chem.. 2007;79:4295-4324.
[Google Scholar]
Salter C., Langhus D.L., . The chemistry of swimming pool maintenance. J. Chem. Educ.. 2007;84:1124.
[Google Scholar]
Shen X., Ye G., Cheng X., Yu C., Yao H., Hu C., . Novel antimicrobial peptides identified from an endoparasitic wasp cDNA library. J. Pept. Sci.. 2010;16:58-64.
[Google Scholar]
Shuang C., Li P., Li A., Zhou Q., Zhang M., Zhou Y., . Quaternized magnetic microspheres for the efficient removal of reactive dyes. Water Res.. 2012;46:4417-4426.
[Google Scholar]
Smieja J.A., . Household water treatments in developing countries. J. Chem. Educ.. 2011;88:549-553.
[Google Scholar]
Song J., Kong H., Jang J., . Bacterial adhesion inhibition of the quaternary ammonium functionalized silica nanoparticles. Colloids Surf. B Biointerfaces. 2011;82:651-656.
[Google Scholar]
Subash B., Krishnakumar B., Swaminathan M., Shanthi M., . ZnS–Ag–ZnO as an excellent UV-light-active photocatalyst for the degradation of AV 7, AB 1, RR 120, and RY 84 dyes: synthesis, characterization, and catalytic applications. Ind. Eng. Chem. Res.. 2014;53:12953-12963.
[Google Scholar]
Teichberg, V.I., 2007. Methods, compositions and devices for maintaining chemical balance of chlorinated water. In: Google Patents.
Umair M.M., Jiang Z., Ullah N., Safdar W., Xie Z., Ren X., . Development and characterisation of antibacterial suture functionalised with N-halamines. J. Ind. Text.. 2015;46:59-74.
[Google Scholar]
Vinodgopal K., Bedja I., Kamat P.V., . Nanostructured semiconductor films for photocatalysis. Photoelectrochemical behavior of SnO2/TiO2 composite systems and its role in photocatalytic degradation of a textile azo dye. Chem. Mater.. 1996;8:2180-2187.
[Google Scholar]
Wang Y., Li L., Liu Y., Ren X., Liang J., . Antibacterial mesoporous molecular sieves modified with polymeric N-halamine. Mater. Sci. Eng., C. 2016;69:1075-1080.
[Google Scholar]
Wang Y., Zhao D., Ma W., Chen C., Zhao J., . Enhanced sonocatalytic degradation of azo dyes by Au/TiO2. Environ. Sci. Technol.. 2008;42:6173-6178.
[Google Scholar]
Waschinski C.J., Zimmermann J., Salz U., Hutzler R., Sadowski G., Tiller J.C., . Design of contact-active antimicrobial acrylate-based materials using biocidal macromers. Adv. Mater.. 2008;20:104-108.
[Google Scholar]
Wenk J., Aeschbacher M., Salhi E., Canonica S., von Gunten U., Sander M., . Chemical oxidation of dissolved organic matter by chlorine dioxide, chlorine, and ozone: effects on its optical and antioxidant properties. Environ. Sci. Technol.. 2013;47:11147-11156.
[Google Scholar]
Wu R., Qu J., Chen Y., . Magnetic powder MnO–Fe2O3 composite—a novel material for the removal of azo-dye from water. Water Res.. 2005;39:630-638.
[Google Scholar]
Xu H., Tong N., Cui L., Lu Y., Gu H., . Preparation of hydrophilic magnetic nanospheres with high saturation magnetization. J. Magn. Magn. Mater.. 2007;311:125-130.
[Google Scholar]
Zhang Z., Yuan, Shi G., Fang Y., Liang L., Ding H., Jin L., . Photoelectrocatalytic activity of highly ordered TiO2 nanotube arrays electrode for azo dye degradation. Environ. Sci. Technol.. 2007;41:6259-6263.
[Google Scholar]
Zhou L., Gao C., Xu W., . Robust Fe3O4/SiO2-Pt/Au/Pd magnetic nanocatalysts with multifunctional hyperbranched polyglycerol amplifiers. Langmuir. 2010;26:11217-11225.
[Google Scholar]
Zollinger H., Iqbal A., . Color Chemistry. Weinheim; Cambridge: Wiley-VCH; 2001.

Introduction

Materials and methods

Materials
Preparation and characterization of magnetic antimicrobial nano-structure
Chlorine content and recharge ability (charge-discharge)
Antibacterial test
Wastewater treatment

Results and discussion

Conclusion

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[1] Abdullah H., Kuo D.-H., . Photocatalytic performance of Ag and CuBiS2 nanoparticle-coated SiO2@TiO2 composite sphere under visible and ultraviolet light irradiation for azo dye degradation with the assistance of numerous nano p–n diodes. J. Phys. Chem. C. 2015;119:13632-13641.
[Google Scholar]

[2] Anion Exchange Resins as Effective Sorbents for Acidic, . Dye removal from aqueous solutions and wastewaters. Solvent Extr. Ion Exch.. 2012;30:507-523.
[Google Scholar]

[3] Badrossamay M.R., Sun G., . Graft polymerization of N-tert-butylacrylamide onto polypropylene during melt extrusion and biocidal properties of its products. Polym. Eng. Sci.. 2009;49:359-368.
[Google Scholar]

[4] Bai R., Zhang Q., Li L., Li P., Wang Y.-J., Simalou O., Zhang Y., Gao G., Dong A., . N-halamine-containing electrospun fibers kill bacteria via a contact/release Co-determined antibacterial pathway. ACS Appl. Mater. Interfaces. 2016;8:31530-31540.
[Google Scholar]

[5] Basiri Parsa J., Merati Z., Abbasi M., . Modeling and optimizing of electrochemical oxidation of C.I. Reactive Orange 7 on the Ti/Sb–SnO2 as anode via response surface methodology. J. Ind. Eng. Chem.. 2013;19:1350-1355.
[Google Scholar]

[6] Bayat S., Ghanbari D., Salavati-Niasari M., . Pechini synthesis of Co2SiO4 magnetic nanoparticles and its application in photo-degradation of azo dyes. J. Mol. Liq.. 2016;220:223-231.
[Google Scholar]

[7] Biswas K., Craik S., Smith D.W., Belosevic M., . Synergistic inactivation of Cryptosporidium parvum using ozone followed by free chlorine in natural water. Water Res.. 2003;37:4737-4747.
[Google Scholar]

[8] Block S.S., . Disinfection, Sterilization, and Preservation. Philadelphia: Lea & Febiger; 2000.

[9] Bokare A.D., Chikate R.C., Rode C.V., Paknikar K.M., . Effect of surface chemistry of Fe−Ni nanoparticles on mechanistic pathways of azo dye degradation. Environ. Sci. Technol.. 2007;41:7437-7443.
[Google Scholar]

[10] Bromberg L., Chang E.P., Alvarez-Lorenzo C., Magariños B., Concheiro A., Hatton T.A., . Binding of functionalized paramagnetic nanoparticles to bacterial lipopolysaccharides and DNA. Langmuir. 2010;26:8829-8835.
[Google Scholar]

[11] Bromberg L., Chang E.P., Hatton T.A., Concheiro A., Magariños B., Alvarez-Lorenzo C., . Bactericidal core-shell paramagnetic nanoparticles functionalized with poly(hexamethylene biguanide) Langmuir. 2011;27:420-429.
[Google Scholar]

[12] Cai X., Han B., Deng S., Wang Y., Dong C., Wang Y., Djerdj I., . Hydrothermal growth of ZnO nanorods on Zn substrates and their application in degradation of azo dyes under ambient conditions. CrystEngComm. 2014;16:7761-7770.
[Google Scholar]

[13] Cao Z., Sun Y., . Polymeric N-halamine latex emulsions for use in antimicrobial paints. ACS Appl. Mater. Interfaces. 2009;1:494-504.
[Google Scholar]

[14] Chen F., Xie S., Huang X., Qiu X., . Ionothermal synthesis of Fe3O4 magnetic nanoparticles as efficient heterogeneous Fenton-like catalysts for degradation of organic pollutants with H2O2. J. Hazard. Mater.. 2017;322:152-162.
[Google Scholar]

[15] Chen Z., Sun Y., . N-halamine-based antimicrobial additives for polymers: preparation, characterization, and antimicrobial activity. Ind. Eng. Chem. Res.. 2006;45:2634-2640.
[Google Scholar]

[16] Cianciolo R.E., Bischoff K., Ebel J.G., Van Winkle T.J., Goldstein R.E., Serfilippi L.M., . Clinicopathologic, histologic, and toxicologic findings in 70 cats inadvertently exposed to pet food contaminated with melamine and cyanuric acid. J. Am. Vet. Med. Assoc.. 2008;233:729-737.
[Google Scholar]

[17] Clasen T., Edmondson P., . Sodium dichloroisocyanurate (NaDCC) tablets as an alternative to sodium hypochlorite for the routine treatment of drinking water at the household level. Int. J. Hyg. Environ. Health. 2006;209:173-181.
[Google Scholar]

[18] Clasen T., Haller L., Walker D., Bartram J., Cairncross S., . Cost-effectiveness of water quality interventions for preventing diarrhoeal disease in developing countries. J. Water Health. 2007;5:599-608.
[Google Scholar]

[19] Crini G., . Studies on adsorption of dyes on beta-cyclodextrin polymer. Bioresour. Technol.. 2003;90:193-198.
[Google Scholar]

[20] Das R., Bhaumik M., Giri S., Maity A., . Sonocatalytic rapid degradation of Congo red dye from aqueous solution using magnetic Fe0/polyaniline nanofibers. Ultrason. Sonochem.. 2017;37:600-613.
[Google Scholar]

[21] Demir B., Cerkez I., Worley S.D., Broughton R.M., Huang T.-S., . N-halamine-modified antimicrobial polypropylene nonwoven fabrics for use against airborne bacteria. ACS Appl. Mater. Interfaces. 2015;7:1752-1757.
[Google Scholar]

[22] Dhale A.D., Mahajani V.V., . Reactive dye house wastewater treatment. Use of hybrid technology: membrane, sonication followed by wet oxidation. Ind. Eng. Chem. Res.. 1999;38:2058-2064.
[Google Scholar]

[23] Disinfection A.W.Q.D., . Committee report -disinfection at large and medium-size systems. J. Am. Water Works Assoc.. 2000;92:32-34.
[Google Scholar]

[24] Dobson R.L.M., Motlagh S., Quijano M., Cambron R.T., Baker T.R., Pullen A.M., Regg B.T., Bigalow-Kern A.S., Vennard T., Fix A., Reimschuessel R., Overmann G., Shan Y., Daston G.P., . Identification and characterization of toxicity of contaminants in pet food leading to an outbreak of renal toxicity in cats and dogs. Toxicol. Sci.. 2008;106:251-262.
[Google Scholar]

[25] Dong A., Lan S., Huang J., Wang T., Zhao T., Xiao L., Wang W., Zheng X., Liu F., Gao G., Chen Y., . Modifying Fe3O4-functionalized nanoparticles with N-halamine and their magnetic/antibacterial properties. ACS Appl. Mater. Interfaces. 2011;3:4228-4235.
[Google Scholar]

[26] Dong A., Sun Y., Lan S., Wang Q., Cai Q., Qi X., Zhang Y., Gao G., Liu F., Harnoode C., . Barbituric acid-based magnetic N-halamine nanoparticles as recyclable antibacterial agents. ACS Appl. Mater. Interfaces. 2013;5:8125-8133.
[Google Scholar]

[27] Dong A., Wang Y.-J., Gao Y., Gao T., Gao G., . Chemical insights into antibacterial N-halamines. Chem. Rev.. 2017;117:4806-4862.
[Google Scholar]

[28] Dong A., Zhang Q., Wang T., Wang W., Liu F., Gao G., . Immobilization of cyclic N-halamine on polystyrene-functionalized silica nanoparticles: synthesis, characterization, and biocidal activity. J. Phys. Chem. C. 2010;114:17298-17303.
[Google Scholar]

[29] Dong Q., Cai Q., Gao Y., Zhang S., Gao G., Harnoode C., Morigen, Dong A., . Synthesis and bactericidal evaluation of imide N-halamine-loaded PMMA nanoparticles. New J. Chem.. 2015;39:1783-1791.
[Google Scholar]

[30] Emerson D.W., . Polymer-bound active chlorine: disinfection of water in a flow system. Polymer supported reagents. 5. Ind. Eng. Chem. Res.. 1990;29:448-450.
[Google Scholar]

[31] Flyunt R., Leitzke A., Mark G., Mvula E., Reisz E., Schick R., von Sonntag C., . Determination of •OH, O2•-, and hydroperoxide yields in ozone reactions in aqueous solution. J. Phys. Chem. B. 2003;107:7242-7253.
[Google Scholar]

[32] Gan G., Liu J., Zhu Z., Yang Z., Zhang C., Hou X., . A novel magnetic nanoscaled Fe3O4/CeO2 composite prepared by oxidation-precipitation process and its application for degradation of orange G in aqueous solution as Fenton-like heterogeneous catalyst. Chemosphere. 2017;168:254-263.
[Google Scholar]

[33] Haham H., Natan M., Gutman O., Kolitz-Domb M., Banin E., Margel S., . Engineering of superparamagnetic core-shell iron oxide/N-chloramine nanoparticles for water purification. ACS Appl. Mater. Interfaces. 2016;8:18488-18495.
[Google Scholar]

[34] Hard G.C., Flake G.P., Sills R.C., . Re-evaluation of kidney histopathology from 13-week toxicity and two-year carcinogenicity studies of melamine in the F344 rat: Morphologic evidence of retrograde nephropathy. Vet. Pathol.. 2009;46:1248-1257.
[Google Scholar]

[35] Jiang Z., Liu Y., Li R., Ren X., Huang T.S., . Preparation of antibacterial cellulose with a monochloro-s-triazine-based N-halamine biocide. Polym. Adv. Technol.. 2016;27:460-465.
[Google Scholar]

[36] Kang J., Han J., Gao Y., Gao T., Lan S., Xiao L., Zhang Y., Gao G., Chokto H., Dong A., . Unexpected enhancement in antibacterial activity of N-halamine polymers from spheres to fibers. ACS Appl. Mater. Interfaces. 2015;7:17516-17526.
[Google Scholar]

[37] Kenawy E.-R., Abdel-Hay F.I., El-Shanshoury A.E.-R.R., El-Newehy M.H., . Biologically active polymers. V. Synthesis and antimicrobial activity of modified poly(glycidyl methacrylate-co-2-hydroxyethyl methacrylate) derivatives with quaternary ammonium and phosphonium salts. J. Polym. Sci., Part A: Polym. Chem.. 2002;40:2384-2393.
[Google Scholar]

[38] Khan Z.U.H., Khan A., Chen Y., Khan A.u., Shah N.S., Muhammad N., Murtaza B., Tahir K., Khan F.U., Wan P., . Photo catalytic applications of gold nanoparticles synthesized by green route and electrochemical degradation of phenolic Azo dyes using AuNPs/GC as modified paste electrode. J. Alloy. Compd.. 2017;725:869-876.
[Google Scholar]

[39] Kocer H.B., Cerkez I., Worley S.D., Broughton R.M., Huang T.S., . N-halamine copolymers for use in antimicrobial paints. ACS Appl. Mater. Interfaces. 2011;3:3189-3194.
[Google Scholar]

[40] Levenspiel O., . Chemical Reaction Engineering. New York; Toronto: Wiley; 1999.

[41] Li C., Hou J., Huang Z., Zhao T., Xiao L., Gao G., Harnoode C., Dong A., . Assessment of 2,2,6,6-tetramethyl-4-piperidinol-based amine N-halamine-labeled silica nanoparticles as potent antibiotics for deactivating bacteria. Colloids Surf. B Biointerfaces. 2015;126:106-114.
[Google Scholar]

[42] Li G., Li Y., Wang Z., Liu H., . Green synthesis of palladium nanoparticles with carboxymethyl cellulose for degradation of azo-dyes. Mater. Chem. Phys.. 2017;187:133-140.
[Google Scholar]

[43] Liu Y., He Q., Li R., Huang D., Ren X., Huang T.-S., . Durable antimicrobial cotton fabrics treated with a novel N-halamine compound. Fibers Polym.. 2016;17:2035-2040.
[Google Scholar]

[44] Liu Y., Zhang G., Chong S., Zhang N., Chang H., Huang T., Fang S., . NiFe(C2O4)x as a heterogeneous Fenton catalyst for removal of methyl orange. J. Environ. Manage.. 2017;192:150-155.
[Google Scholar]

[45] Ma K., Liu Y., Xie Z., Li R., Jiang Z., Ren X., Huang T.-S., . Synthesis of novel N-halamine epoxide based on cyanuric acid and its application for antimicrobial finishing. Ind. Eng. Chem. Res.. 2013;52:7413-7418.
[Google Scholar]

[46] Ma W., Li L., Li J., Ren X., Gu Z.-G., Huang T.-S., . Antibacterial PVA membranes containing TiO2/N-halamine nanoparticles. Adv. Polym. Tech. 2017 n/a-n/a
[Google Scholar]

[47] Mahmoodi N.M., Keshavarzi S., Ghezelbash M., . Synthesis of nanoparticle and modelling of its photocatalytic dye degradation ability from colored wastewater. J. Environ. Chem. Eng.. 2017;5:3684-3689.
[Google Scholar]

[48] Milne, G.W.A., Wiley, I., 2005. Gardner's commercially important chemicals: synonyms, trade names, and properties. Hoboken, N.J.: Wiley-Interscience.

[49] Munoz M., de Pedro Z.M., Casas J.A., Rodriguez J.J., . Preparation of magnetite-based catalysts and their application in heterogeneous Fenton oxidation – A review. Appl. Catal. B. 2015;176–177:249-265.
[Google Scholar]

[50] Nadupalli S., Koorbanally N., Jonnalagadda S.B., . Kinetics and mechanism of the oxidation of amaranth with hypochlorite. J. Phys. Chem. A. 2011;115:7948-7954.
[Google Scholar]

[51] Narayani H., Augustine R., Sumi S., Jose M., Deepa Nair K., Samsuddin M., Prakash H., Shukla S., . Removal of basic and industrial azo reactive dyes from aqueous solutions via Fenton-like reactions using catalytic non-magnetic Pd-flyash and magnetic Pd-Fe3O4-flyash composite particles. Sep. Purif. Technol.. 2017;172:338-349.
[Google Scholar]

[52] Nataro J.P., Kaper J.B., . Diarrheagenic Escherichia coli. Clin. Microbiol. Rev.. 1998;11:142-201.
[Google Scholar]

[53] Osborne C.A., Lulich J.P., Ulrich L.K., Koehler L.A., Albasan H., Sauer L., Schubert G., . Melamine and cyanuric acid-induced crystalluria, uroliths, and nephrotoxicity in dogs and cats. Veterinary Clinics of North America - Small Animal Practice. 2009;39:1-14.
[Google Scholar]

[54] Oxspring D.A., McMullan G., Smyth W.F., Marchant R., . Decolourisation and metabolism of the reactive textile dye, Remazol Black B, by an immobilized microbial consortium. Biotechnol. Lett.. 1996;18:527-530.
[Google Scholar]

[55] Padmanabhuni R.V., Luo J., Cao Z., Sun Y., . Preparation and characterization of N-halamine-based antimicrobial fillers. Ind. Eng. Chem. Res.. 2012;51:5148-5156.
[Google Scholar]

[56] Perdigao L.M.A., Champness N.R., Beton P.H., . Surface self-assembly of the cyanuric acid-melamine hydrogen bonded network. Chem. Commun. 2006:538-540.
[Google Scholar]

[57] Predicting azo dye toxicity, 1993. Critical Reviews in Environmental Science and Technology, 23, 249–324.

[58] Qiao M., Ren T., Huang T.-S., Weese J., Liu Y., Ren X., Farag R., . N-Halamine modified thermoplastic polyurethane with rechargeable antimicrobial function for food contact surface. RSC Adv.. 2017;7:1233-1240.
[Google Scholar]

[59] Quain D.E., . Draught beer hygiene: cleaning of dispense tap nozzles. J. Inst. Brew.. 2016;122:388-396.
[Google Scholar]

[60] Ran X., Wang L., Cao D., Lin Y., Hao J., . Synthesis, characterization and in vitro biological activity of cobalt(II), copper(II) and zinc(II) Schiff base complexes derived from salicylaldehyde and D, L-selenomethionine. Appl. Organomet. Chem.. 2011;25:9-15.
[Google Scholar]

[61] Reimschuessel R., Gieseker C.M., Miller R.A., Ward J., Boehmer J., Rummel N., Heller D.N., Nochetto C., de Alwis G.K.H., Bataller N., Andersen W.C., Turnipseed S.B., Karbiwnyk C.M., Satzger R.D., Crowe J.B., Wilber N.R., Reinhard M.K., Roberts J.F., Witkowski M.R., . Evaluation of the renal effects of experimental feeding of melamine and cyanuric acid to fish and pigs. Am. J. Vet. Res.. 2008;69:1217-1228.
[Google Scholar]

[62] Ren F.Y., Wang Y., Hou X.B., Zhang C.R., Ling M., . Clinical and imaging features in 16 infants exposed to food contaminated with melamine and cyanuric acid. Am. J. Roentgenol.. 2009;192:707-710.
[Google Scholar]

[63] Richardson S.D., . Water analysis: emerging contaminants and current issues. Anal. Chem.. 2007;79:4295-4324.
[Google Scholar]

[64] Salter C., Langhus D.L., . The chemistry of swimming pool maintenance. J. Chem. Educ.. 2007;84:1124.
[Google Scholar]

[65] Shen X., Ye G., Cheng X., Yu C., Yao H., Hu C., . Novel antimicrobial peptides identified from an endoparasitic wasp cDNA library. J. Pept. Sci.. 2010;16:58-64.
[Google Scholar]

[66] Shuang C., Li P., Li A., Zhou Q., Zhang M., Zhou Y., . Quaternized magnetic microspheres for the efficient removal of reactive dyes. Water Res.. 2012;46:4417-4426.
[Google Scholar]

[67] Smieja J.A., . Household water treatments in developing countries. J. Chem. Educ.. 2011;88:549-553.
[Google Scholar]

[68] Song J., Kong H., Jang J., . Bacterial adhesion inhibition of the quaternary ammonium functionalized silica nanoparticles. Colloids Surf. B Biointerfaces. 2011;82:651-656.
[Google Scholar]

[69] Subash B., Krishnakumar B., Swaminathan M., Shanthi M., . ZnS–Ag–ZnO as an excellent UV-light-active photocatalyst for the degradation of AV 7, AB 1, RR 120, and RY 84 dyes: synthesis, characterization, and catalytic applications. Ind. Eng. Chem. Res.. 2014;53:12953-12963.
[Google Scholar]

[70] Teichberg, V.I., 2007. Methods, compositions and devices for maintaining chemical balance of chlorinated water. In: Google Patents.

[71] Umair M.M., Jiang Z., Ullah N., Safdar W., Xie Z., Ren X., . Development and characterisation of antibacterial suture functionalised with N-halamines. J. Ind. Text.. 2015;46:59-74.
[Google Scholar]

[72] Vinodgopal K., Bedja I., Kamat P.V., . Nanostructured semiconductor films for photocatalysis. Photoelectrochemical behavior of SnO2/TiO2 composite systems and its role in photocatalytic degradation of a textile azo dye. Chem. Mater.. 1996;8:2180-2187.
[Google Scholar]

[73] Wang Y., Li L., Liu Y., Ren X., Liang J., . Antibacterial mesoporous molecular sieves modified with polymeric N-halamine. Mater. Sci. Eng., C. 2016;69:1075-1080.
[Google Scholar]

[74] Wang Y., Zhao D., Ma W., Chen C., Zhao J., . Enhanced sonocatalytic degradation of azo dyes by Au/TiO2. Environ. Sci. Technol.. 2008;42:6173-6178.
[Google Scholar]

[75] Waschinski C.J., Zimmermann J., Salz U., Hutzler R., Sadowski G., Tiller J.C., . Design of contact-active antimicrobial acrylate-based materials using biocidal macromers. Adv. Mater.. 2008;20:104-108.
[Google Scholar]

[76] Wenk J., Aeschbacher M., Salhi E., Canonica S., von Gunten U., Sander M., . Chemical oxidation of dissolved organic matter by chlorine dioxide, chlorine, and ozone: effects on its optical and antioxidant properties. Environ. Sci. Technol.. 2013;47:11147-11156.
[Google Scholar]

[77] Wu R., Qu J., Chen Y., . Magnetic powder MnO–Fe2O3 composite—a novel material for the removal of azo-dye from water. Water Res.. 2005;39:630-638.
[Google Scholar]

[78] Xu H., Tong N., Cui L., Lu Y., Gu H., . Preparation of hydrophilic magnetic nanospheres with high saturation magnetization. J. Magn. Magn. Mater.. 2007;311:125-130.
[Google Scholar]

[79] Zhang Z., Yuan, Shi G., Fang Y., Liang L., Ding H., Jin L., . Photoelectrocatalytic activity of highly ordered TiO2 nanotube arrays electrode for azo dye degradation. Environ. Sci. Technol.. 2007;41:6259-6263.
[Google Scholar]

[80] Zhou L., Gao C., Xu W., . Robust Fe3O4/SiO2-Pt/Au/Pd magnetic nanocatalysts with multifunctional hyperbranched polyglycerol amplifiers. Langmuir. 2010;26:11217-11225.
[Google Scholar]

[81] Zollinger H., Iqbal A., . Color Chemistry. Weinheim; Cambridge: Wiley-VCH; 2001.