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• Chemistry, properties, and issues of pharmaceuticals contamination in water are discussed. • Conventional technologies proved ineffective in treating pharmaceuticals wastewater. • Efficiency, mechanisms and pathways of different •OH and SO 4 •−-based AOPs are discussed. • Effects of different process parameters and cost associated with different AOPs are discussed. • The proposed pathways and ecotoxicities of pharmaceuticals degradation are discussed. Pharmaceuticals comprises different drugs used for treating different infections in human being and animals. The huge quantities of pharmaceuticals used are found to discharge into different water resources and cause different health and environmental problems. The continuous and large-scale discharge of pharmaceuticals increases their persistency which can consequently make them more toxic. The different advanced oxidation processes (AOPs) were found to effectively treat pharmaceuticals contaminated water. The AOPs showed high efficiency in the treatment of acetaminophen, sulfamethoxazole, metronidazole. ciprofloxacin. sulfadiazine, sulfamethazine, amoxicillin, ibuprofen, carbamazepine, and tetracycline. The pharmaceuticals, amitrole, norfloxacin, atenolol, chloramphenicol, berberine, diclofenac, and sulfadiazine showed persistency to some AOPs. The AOPs yield different reactive radicals with predominantly hydroxyl radical (•OH)- and sulfate radical (SO 4 •−) which showed fast reactivity with pharmaceuticals. Different mechanistic approaches were systematically reviewed which verify the yield, reactivities, and degradation pathways of •OH and SO 4 •−. Different factors, such as pH, dose of peroxides and activators, level of pharmaceuticals contamination, and common inorganic anions were found to influence the effectiveness of AOPs. The effectiveness of the AOPs in term of cost and detoxification of target pharmaceuticals suggested to select preferably AOPs which are economical and form non-toxic and/or less toxic products. The different challenges, such as treatment of mixture of pharmaceuticals and treatment in real wastewater which can further increase potential of treatment are discussed. [ABSTRACT FROM AUTHOR]

[Display omitted] • Treatment of CIP was compared by different activated PMS-based process. • The UV-C/Fe2+/PMS-based process gave better performance in the removal of CIP. • The activated PMS yielded ●OH and SO 4 ●− which showed high reactivity with CIP. • The Cu2+ improve production rate of ●OH and SO 4 ●− and facilitated removal of CIP. • Degradation products and ecotoxicities of CIP and its DPS were analyzed. Ciprofloxacin (CIP) is a valuable antibiotic and discharged in huge quantities in aquatic environment. Different •OH and SO 4 •−-based advanced oxidation technologies (AOTs), e.g., Fe2+/PMS, UV-C/PMS, and UV-C/Fe2+/PMS are developed for treatment of CIP. The removal of CIP by Fe2+/PMS, UV-C/PMS and UV-C/Fe2+/PMS was 63, 77, and 87 %, respectively, under identical conditions which showed better performance of UV-C/Fe2+/PMS. The UV-C/Fe2+/PMS also caused high removal of total organic carbon of CIP. This high performance of UV-C/Fe2+/PMS-based AOTs possibly looked due to dual activation of PMS by UV-C and Fe2+. The removal of CIP by the three AOTs was found due to •OH and SO 4 •− and the later showed high reactivities with CIP, i.e., 2.45 × 109 and 2.35 × 109 M−1 s−1, respectively. The study of factors affecting the reactivities and/or yield of •OH and SO 4 •− diminished CIP degradation efficiency. The change in pH of solution and temperature and doses of Fe2+, PMS, and CIP exhibited significant impacts on the removal of CIP. The addition of inorganic ions showed strong inhibiting effects of NO 2 –, CO 3 2–, and HCO 3 – while Cu2+ showed facilitating role. Analysis of degradation of CIP by GC–MS was used to develop proposed pathways. Acute and chronic toxicities of CIP and its products were measured by ECOSAR program and showed the resulting products to be non-toxic. [ABSTRACT FROM AUTHOR]

In this study, activated carbon (AC) and nano-zerovalent copper (nZVCu) functionalized hydroxyapatite (HA) and alginate beads were synthesized and used for the removal of As3+ from aqueous solution. The characterization by X-ray diffraction, scanning electron microscopy, X-ray energy dispersive spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, high resolution transmission electron microscopy, BET surface area analysis, thermogravimetric analysis, and Fourier transform infrared spectroscopy revealed successful formation of the AC/nZVCu/HA-alginate, nZVCu/HA-alginate, AC/HA-alginate, and HA-alginate beads. The scanning electron microscopy and surface analysis revealed the prepared beads to be highly mesoporous which led to the maximum adsorption of As3+, i.e., 13.97, 29.33, 30.96, and 39.06 mg/g by HA-alginate, AC/HA-alginate, nZVCu/HA-alginate, and AC/nZVCu/HA-alginate beads, respectively. The thermogravimteric analysis showed the nZVCu/HA-alginate beads to be highly stable while the AC composite beads as the least stable to heat treatment. The HA-alginate beads achieved 39% removal of As3+, however, removal efficiency was promoted to 95% by coupling AC and nZVCu with HA-alginate beads at a reaction time of 120 min. The removal of As3+ by the prepared AC & nZVCu coupled HA-alginate beads was promoted with increasing [As3+] 0 and [AC/nZVCu/HA-alginate] 0. The pH of aqueous solution significantly influenced the removal of As3+ by AC/nZVCu/HA-alginate beads and maximum removal was achieved at pH 5.8. Freundlich adsorption isotherm and pseudo-second-order kinetic models were found to best fit the removal of As3+ by the synthesized beads. The high performance of AC/nZVCu/HA-alginate beads in the removal of As3+ even after seven cyclic treatment as well as least leaching of Cu ions into aqueous solution suggest enhanced reusability and stability of HA-alginate beads by coupling with AC and nZVCu. The results suggest that the synthesized beads have good potential for the removal of As3+ from aqueous solutions. Image 1 • Characterization techniques proved nZVCu and AC coupled HA-Alginate beads formation. • Coupling AC and nZVCu enhanced performance and reusability of HA-Alginate beads. • Removal of As3+ best fitted Freundlich isotherm and pseudo-second-order models. • Removal of As3+ was significantly affected by the pH of aqueous solution. [ABSTRACT FROM AUTHOR]

Abstract Removal of cadmium (Cd2+), a highly toxic heavy metal, from aqueous solutions was investigated using nano zerovalent iron (Fe0). Cadmium was efficiently removed by Fe0, although reactivity and reusability of Fe0 was significantly promoted by coupling with bismuth (Bi). At a reaction time of 20 min, 85% and 96% Cd2+ was removed by Fe0 and Bi/Fe0, respectively, at first cycle using [Cd2+] 0 = 10 mg/L and [Fe0] 0 = [Bi/Fe0] 0 = 1.0 g/L. However, Cd2+ removal efficiency was reduced to 12% and 80% at sixth cycle by Fe0 and Bi/Fe0, respectively. The X-Ray diffraction and energy dispersive X-Ray spectroscopy analysis proved successful formation of Fe0 by the chemical reduction method and also confirmed coupling of Bi with Fe0 to form bimetallic Bi/Fe0. The oxidation of Fe0 and Bi/Fe0 yielded electron that played significant role in the conversion of toxic Cd2+ into non-toxic Cd0. The reactivity of electron with Cd2+ was calculated to be 4.3 × 109 M−1 s−1. The pH of solution showed pronounced effects on the reactivity of both Fe0 and Bi/Fe0. Removal of Cd2+ by both Fe0 and Bi/Fe0 followed pseudo-first-order kinetic model. The conversion of Cd2+ into non-toxic Cd0 proved Fe0 and Bi/Fe0 to be highly efficient and rewarding in detoxification of Cd2+ and other toxic metals in aqueous environments. Graphical abstract Unlabelled Image Highlights • Bi was successfully coupled with Fe0 using chemical reduction method. • The Bi coupled Fe0 displayed greater reactivity, stability, and reusability. • Second-order rate constant of hydrated electron with Cd2+ was estimated. • pH of aqueous solution significantly influenced efficiency of Fe0 and Bi/Fe0. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Highly stable nZVMn was synthesized by chemical reduction method. • Addition of S 2 O 8 2− promoted the performance of nZVMn. • Second-order rate constants of CIP with OH and SO4 − were calculated. • Proposed pathways for conversion of CIP into TPs were developed. • Acute and chronic toxicities of CIP and its TPs were evaluated. Abstract Nano zerovalent manganese (nZVMn, Mn0) materials have been synthesized in this study and used for degradation of ciprofloxacin (CIP), an emerging water pollutant. The investigation of physiological characteristics of Mn0 by different characterization techniques proved successful formation of Mn0 by the chemical reduction method and found it to be highly crystalline. The Mn0 was highly efficient and resulted in 63% degradation of CIP using [CIP] 0 = 10 mg/L and [Mn0] 0 = 1.0 g/L at a reaction time of 80 min. Addition of S 2 O 8 2− to Mn0 promoted removal efficiency of CIP from 63 to 95% at a reaction time of 80 min using the conditions of [CIP] 0 = 10 mg/L, [Mn0] 0 = 1.0 g/L, and [S 2 O 8 2−] 0 = 50 mg/L. The presence of OH and SO 4 − scavengers inhibited the degradation of CIP by Mn0/S 2 O 8 2−. The comparable second-order rate constants of CIP with OH and SO 4 − were calculated to be 2.35 × 109 and 2.10 × 109 M−1 s−1, respectively. High S 2 O 8 2− and Mn0 concentrations and low pH accelerated the degradation of CIP. However, removal efficiency of CIP by Mn0 with the added S 2 O 8 2− was inhibited using high CIP concentration, high pH, inorganic anions, and NOM. Degradation pathways from OH and SO 4 − based degradation of CIP were developed. Acute and chronic toxicities of CIP and its products were estimated, showing the final product to be non-toxic. The as-synthesized Mn0 was found to be stable as well as environmentally friendly for treating CIP. This study suggests that Mn0 with the added S 2 O 8 2− is a promising alternative for potential remediation and detoxification of CIP and other emerging water pollutants. [ABSTRACT FROM AUTHOR]

In this study, solar light responsive Bi 3+ and Fe 2+ doped ZnO were synthesized and used for photocatalytic degradation of norfloxacin (NOR), an emerging water pollutant. Analysis with Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), and UV–vis diffuse reflectance spectroscopy (DRS) confirmed coupling of dopants (i.e., Bi 3+ and Fe 2+ ) or co-dopants (Bi 3+ /Fe 2+ ) with ZnO and suggested small narrow size as well as highly crystalline and porous nature of the doped ZnO. Metal ions doping lowered band gap energy and inhibited recombination of electron-hole pair in the as-synthesized ZnO. Consequently, BiFe-ZnO showed enhanced photocatalytic activity and reusability, giving 80% removal of NOR as compared to 36% by un-doped ZnO at a reaction time of 120 min. The analysis with photoluminescence (PL) technique verified high yield of OH from solar light activation of BiFe-ZnO compared to Bi-ZnO, Fe-ZnO and ZnO. Performance of the as-prepared photocatalysts was promoted with the added HSO 5 − and increased with increasing [HSO 5 − ] 0 . Degradation of NOR by BiFe-ZnO with the added HSO 5 − was due to OH and SO 4 − and NOR showed high reactivity with OH and SO 4 − . The removal efficiency of NOR was inhibited using OH and SO 4 − scavengers. Photocatalytic activity of the as-synthesized photocatalysts with the added HSO 5 − was highly dependent on [NOR] 0 , [pH] 0 , co-existing ions, and natural organic matter. Degradation pathways were suggested from the pattern of NOR degradation and identified transformation products. The mineralization of NOR as well as formation of non-toxic end product suggests co-doped ZnO with added HSO 5 − to be a potential technology for treating antibiotics contaminated water. [ABSTRACT FROM AUTHOR]

Ciprofloxacin (CIP) is a widespread emerging water pollutant and thus its removal from aquatic environment is vital. The use of Fe3+/H2O2 and Fe2+/H2O2 resulted in 38 and 64% removal of CIP (8.0 ppm), respectively, within 80 min reaction time (pH 5.8, [H2O2]0 = 80 ppm, and [iron]0 = 20 ppm). Low pH, high temperature, high dose of H2O2 and Fe2+, and low CIP concentration facilitated removal of CIP. The radical scavenger studies proved in situ generated OH to be involved primarily in the removal of CIP. The effect of temperature was used to estimate enthalpy and activation energies of the removal of CIP. At 800 min reaction time, the Fe2+/H2O2 resulted in 54% mineralization of CIP using 16.0 ppm [CIP]0, 320.0 ppm [H2O2]0, and 40.0 ppm [Fe2+]0. The potential degradation pathways of CIP established from the degradation of CIP by OH and products evolved was found to be initiated at C6 through the loss of fluoride ion. The acute and chronic toxicities of CIP and its degradation products were estimated with the final product found to be non-toxic. The results suggest that Fe2+/H2O2-mediated AOPs have high potential for degradation as well as toxicity elimination of CIP and its degradation products. [ABSTRACT FROM AUTHOR]

• The presence of H 2 O 2 with iron promoted the removal of CIP. • The presence of OH scavengers inhibited removal of CIP by Fe2+/H 2 O 2. • Mineralization of CIP by Fe2+/H 2 O 2 -mediated AOPs was explored. • Potential pathways for conversion of CIP into degradation products were developed. • Acute and chronic toxicities of CIP and its degradation products were estimated. Ciprofloxacin (CIP) is a widespread emerging water pollutant and thus its removal from aquatic environment is vital. The use of Fe3+/H 2 O 2 and Fe2+/H 2 O 2 resulted in 38 and 64% removal of CIP (8.0 ppm), respectively, within 80 min reaction time (pH 5.8, [H 2 O 2 ] 0 = 80 ppm, and [iron] 0 = 20 ppm). Low pH, high temperature, high dose of H 2 O 2 and Fe2+, and low CIP concentration facilitated removal of CIP. The radical scavenger studies proved in situ generated OH to be involved primarily in the removal of CIP. The effect of temperature was used to estimate enthalpy and activation energies of the removal of CIP. At 800 min reaction time, the Fe2+/H 2 O 2 resulted in 54% mineralization of CIP using 16.0 ppm [CIP] 0 , 320.0 ppm [H 2 O 2 ] 0 , and 40.0 ppm [Fe2+] 0. The potential degradation pathways of CIP established from the degradation of CIP by OH and products evolved was found to be initiated at C 6 through the loss of fluoride ion. The acute and chronic toxicities of CIP and its degradation products were estimated with the final product found to be non-toxic. The results suggest that Fe2+/H 2 O 2 -mediated AOPs have high potential for degradation as well as toxicity elimination of CIP and its degradation products. [ABSTRACT FROM AUTHOR]

The drug resistant bacteria and textile contaminations of water cause different sever health problem throughout the world. To overcome this issue, new environmental benign materials and methods are needed. Plant metabolites directed synthesis of nanoparticles is considered eco-friendly and easy in synthesis. Therefore, it was explicit for the synthesis of AgNPs. The prepared AgNPs were evaluated for antibacterial, antioxidant, photo-catalytic and electrochemical degradation properties as well as toxicity of degradation products on aquatic life. X-Ray Photoelectron Spectroscopy (XPS) has been used for analyzing the surface chemistry of prepared AgNPs. The particle size determines the interaction of nanoparticles with pathogens. Both Gram positive and negative bacteria ( Escherichia coli and Staphylococcus areous ) are used to determine the anti-microbial potency of the green synthesized AgNPs. The synthesized silver nanoparticles showed significant anti-bacterial applications against B. subtilus and S. aureus. The anti-oxidant applications of AgNPs also studied on comparison with vitamin C. The toxicity of the phenolic Azo dyes (PDA) has been studied against Fish, Daphnia and Green Algae . The electrode potential was studied in the electrochemical redox reaction of hydroxy phenol in aqueous media. Simple electrolyte was used to determine the current efficiency. For the stability of electrode multi cyclic voltammetry was also studied during redox reaction, which showed stability under the potential 0.4 to 0.2 V. [ABSTRACT FROM AUTHOR]

A highly efficient, quick and environmentally benign protocol has been adopted to synthesize AuNPs using the plant extract of Sueda fruciotosa . UV–vis spectroscopy, XRD, HRTEM, SEM and FTIR were used to characterize the prepared AuNPs. Different concentrations of plant extract were used to optimize the size, morphology and distribution of AuNPs. AuNPs were of small size and spheroid in shape at lower concentration. AuNPs showed a surface plasmon resonance at 443 nm. According to HRTEM the average size of AuNPs was 6–8 nm. The AuNPs were appraised for their photo degradation activity on methylene blue (MB) as an experimental substrate. Photo-catalytic activity of AuNPs was found to be dependent on the concentration of catalyst, irradiation time, size and aggregation of AuNPs. Furthermore, AuNPs exhibited an excellent electro-catalytic activity. The sensitivity of modified AuNPs was also studied for phenolic Azo dyes (PAD) which showed its good degradation activity. These gold nanoparticles found to be significantly applicable in the field of electrochemistry, sensors, catalysis, nano-devices, treatment of waste water and conversion of toxic agents into less toxic compound. [ABSTRACT FROM AUTHOR]

Bromate, a potential carcinogen, is a well known highly persistent and environmentally recalcitrant contaminant. UV-254/sulfite-based advanced reductive pathways (ARPs) were proposed to eliminate bromate successfully from water. Experiments with N 2 , N 2 O, 2-chlorophenol, inorganic ions, and different pH (highly acidic to highly basic) proved that UV-254/sulfite successfully provides aqueous electron that effectively participate in bromate removal from water. Significant removal, 86%, of initially 39.0 µM bromate was achieved by UV-254/sulfite under conditions that dominate aqueous electron based pathways. The high second-order rate constant of 5.3 × 10 9 M −1 s −1 determined proved high reactivity of aqueous electron with bromate. The kinetic and removal efficiency of bromate showed linear relationship with the rate of aqueous electron formation. An increase in kinetic and removal efficiency of bromate was observed with increasing initial sulfite concentration and decreasing bromate concentration. The impacts of different initial concentrations of the typical ions commonly found in water were studied in detail to extend the UV-254/sulfite-based process for potential practical applications. The lower molar absorptivity of bromate at 254 nm determined proved insignificant removal of bromate under direct photolysis. The impacts of initial sulfite concentration on removal of bromate in UV-254/sulfite-based process also minimized role of direct photolysis. The cost evaluation and rapid decomposition of bromate into bromide proved UV-254/sulfite-based ARPs to be economical and highly rewarding in efficient decomposition of bromate and other inorganic oxyhalides. [ABSTRACT FROM AUTHOR]

Removal of chlorendic acid, an emerging water pollutant and potential carcinogenic, was investigated by gamma radiation in the absence and presence of peroxymonosulfate (PMS, HSO 5 − ). The removal of chlorendic acid (1.40 μM initial concentration) by gamma radiation was promoted with PMS, i.e., 95% compared to 82% in the absence of PMS, at an absorbed dose of 1000 Gy. The removal of chlorendic acid by gamma-ray/PMS process was due to OH and SO 4 − . Second-order rate constants of 5.90 × 10 9 , 1.75 × 10 9 , and 2.05 × 10 9 M −1 s −1 for chlorendic acid with e aq − , OH, and SO 4 − , respectively, were determined. The removal efficiency of chlorendic acid was promoted with increasing initial PMS concentration and decreasing initial target contaminant concentration. The removal of chlorendic acid by gamma-ray/PMS was inhibited in the presence of CO 3 2− , NO 2 − , p -CBA, m -TA, and alcohols. The presence of Fe 2+ , Cu + , and Fe 3+ with gamma-ray/PMS promoted removal efficiency of chlorendic acid from 78% to 99, 94, and 89%, respectively, at 592 Gy. The degradation of chlorendic acid by OH and SO 4 − was found to be initiated at the carboxylate group as could be revealed from nature of the transformation by-products. Nevertheless, this study concluded that gamma-ray/PMS is of practical importance in treatment of natural water containing chlorendic acid, as potential detoxification of chlorendic acid solution can be revealed from 83% loss of chloride ion at 3000 Gy. In addition, gamma-ray/PMS process achieved efficient removal of chlorendic acid even in the presence of commonly found inorganic ions in natural water. [ABSTRACT FROM AUTHOR]

Norfloxacin (NOR), an important antibiotic used for the treatment of different infections which is reportedly causing huge quantity of water pollution and severe environmental issues. In this study, biochar prepared from Phoenix dactylifera roots biomass (PB) and composited with mesoporous nano-zerovalent cerium (nZVCe) was used for treatment of NOR solutions. The various characterization and treatment studies showed successful formation of the nZVCe and PB composite. The nZVCe was found to improve physiological characteristics and catalytic efficiency of PB. The nZVCe/PB composite caused 52% removal of NOR as compared to 23% by the individual PB. The use of peroxydisulfate (PDS) with PB and nZVCe/PB showed further improvement in the removal of NOR and caused 58 and 84% removal efficiencies of NOR by PB/PDS and nZVCe/PB/PDS, respectively. The use of PDS with PB and nZVCe/PB was found to yield ●OH and SO 4 ●– which improved degradation of NOR, however, addition of ●OH and SO 4 ●– scavengers impeded NOR degradation. The PB was found to have several oxygen functional groups which decomposed PDS into ●OH and SO 4 ●–. The nZVCe/PB showed high recovery, reusability, and stability and caused high removal of NOR even at fifth cycle of treatment both in the absence and presence of PDS. The treatment of NOR by nZVCe/PB-catalyzed PDS showed encouraging results under different pH, and varying concentrations of PDS, nZVCe/PB, and NOR as well as in real water samples which suggest potential practical applications of NOR contaminated water. Degradation of NOR resulted into several products and the resulting final product proved to be non-toxic. [Display omitted] • nZVCe and biochar composite was prepared and nZVCe improved properties of biochar. • Biochar and nZVCe/PB effectively decomposed PDS into.●OH and SO 4 ●–. • Radical scavengers inhibited role of.●OH and SO 4 ●– in degradation of norfloxacin. • The PB and nZVCe/PB effectively degraded norfloxacin in real water also. • The composite of biochar and nZVCe showed enhanced stability and reusability. [ABSTRACT FROM AUTHOR]

This study reports the radiation-induced degradation of an extensively used carcinogenic, endocrine disrupting and persistent herbicide, atrazine, in aqueous solution. The atrazine degradation rate was directly proportional whereas the dose constant was inversely proportional to the irradiation dose rate and initial atrazine concentration. The second-order rate constant of atrazine with e aq − and H were found to be 3.70 × 10 9 and 4.84 × 10 8 M −1 s −1 , respectively. Humic acid has synergistic whereas hydrogen peroxide and chloroform have an inhibitory impact on atrazine degradation. Atrazine degradation was reduced in the presence of 1 mM of each of NO 3 − , NO 2 − , Br − , SO 4 2− , HCO 3 − and CO 3 2− due to their competition for reactive radicals with atrazine. The attack of e aq − and OH on atrazine successfully mineralized the organic chlorine and nitrogen to chloride, nitrate and ammonium ions, in addition to the formation of acetate ions from carbon atoms of side chains. Potential detoxification of atrazine solution could be revealed from 83% loss of chloride ion at an absorbed dose of 4000 Gy. The findings of this study suggested that atrazine can efficiently be removed from water by gamma-ray irradiation even in the presence of organic and inorganic radical scavengers commonly found in natural water. [ABSTRACT FROM AUTHOR]

This study investigated iron-mediated oxidative processes for the photochemical degradation of endosulfan, a chlorinated insecticide and central nervous system disruptor. At UV fluence of 360 mJ/cm 2 , 52.4% and 32.0% removal of 2.45 μM initial endosulfan was observed by UV/Fe 3+ and UV/Fe 2+ processes, respectively, at an initial concentration of 17.8 μM iron. The degradation of endosulfan by UV/Fe 3+ or UV/Fe 2+ was dramatically enhanced by adding peroxide (i.e., H 2 O 2 , S 2 O 8 2− or HSO 5 − ). Among the UV/peroxide/Fe processes, the highest degradation efficiency of 99.0% at UV fluence of 360 mJ/cm 2 was observed by UV/HSO 5 − /Fe 2+ with 2.45 μM [endosulfan] 0 , 17.8 μM [Fe 2+ ] 0 , and 49.0 μM [HSO 5 − ] 0 . The observed degradation rate constant of endosulfan was promoted either by increasing [Fe 2+ ] 0 and/or [peroxide] 0 or by decreasing [endosulfan] 0 , while the initial degradation rate of endosulfan increased with increasing [Fe 2+ ] 0 , [peroxide] 0 , or [endosulfan] 0 . At UV fluence of 6000 mJ/cm 2 , 45.0% mineralization as represented by the decrease in total organic carbon content was observed by UV/HSO 5 − /Fe 2+ at 9.80 μM [endosulfan] 0 , 980 μM [HSO 5 − ] 0 , and 17.8 μM [Fe 2+ ] 0 . The major by-product of endosulfan was observed in all cases to be endosulfan ether which was further degraded with an extended reaction time. The results suggest that iron-mediated advanced oxidation processes (AOPs) have a high potential for the removal of endosulfan and its by-product from contaminated water. [ABSTRACT FROM AUTHOR]

The degradation of atrazine was investigated in aqueous solution by gamma-ray irradiation. 8.11 μM initial atrazine concentration could be completely removed in N 2 saturated solution by applying 3500 Gy radiation dose at a dose rate of 296 Gy h −1 . Significant removal of atrazine (i.e., 39.4%) was observed at an absorbed dose of 1184 Gy in air saturated solution and the removal efficiency was promoted to 50.5 and 65.4% in the presence of N 2 O and N 2 gases, respectively. The relative contributions of hydrated electron, hydroxyl radical and hydrogen radical toward atrazine degradation were determined as ratio of observed dose constant ( k obs ) and found to be 5: 3: 1 for k eaq − : k OH : k H , respectively. The degradation efficiency of atrazine was 69.5, 55.6 and 37.3% at pH 12.1, 1.7 and 5.7, respectively. A degradation mechanism was proposed based on the identified degradation by-products by gas chromatography–mass spectrometry. Taking the relative contributions of oxidative and reductive species to atrazine degradation into account, reductive pathway proved to be a better approach for the radiolytic treatment of atrazine contaminated water. [ABSTRACT FROM AUTHOR]

The gamma irradiation was investigated for potential removal of endosulfan sulfate, an emerging water pollutant and central nervous system disruptor. A removal efficiency of 99.5% of initially 1.30 μM endosulfan sulfate was observed at an absorbed dose of 1020 Gy. Aqueous electron (e aq − ) was found to play primary role in the removal of endosulfan sulfate which was possibly due to greater reactivity of e aq − with endosulfan sulfate, considering the second-order rate constant of 8.1 × 10 9 and 3.4 × 10 10 M −1 s −1 for hydroxyl radical ( OH) and e aq − , respectively, with endosulfan sulfate. The removal efficiency of endosulfan sulfate was affected by the pH of aqueous solution, with observed removal efficiency of 99.5%, 98.3% and 31.3% at pH 6.2, pH 10.0, and pH 2.6, respectively. The efficiency was also influenced by inorganic anions and humic acid in the order of nitrate > nitrite > bicarbonate > carbonate ≃ humic acid. The initial degradation rate increased while degradation constant decreased with increasing initial concentrations of endosulfan sulfate. The degradation pathways showed that oxidative pathway was initiated at the SO 2 bond while reductive pathways at the chlorine attached to the ring of endosulfan sulfate. The mass balance showed removal of 98% chloride and 72% sulfate ions from endosulfan sulfate at an absorbed dose of 1020 Gy. The removal of endosulfan sulfate followed by subsequent loss of by-products under extended treatment showed that gamma irradiation is potential technique for the remediation of organic pollutants from a water environment. [ABSTRACT FROM AUTHOR]

The removal of endosulfan, an emerging water pollutant, from water was investigated using gamma irradiation based advanced oxidation and reduction processes (AORPs). A significant removal, 97% of initially 1.0 µM endosulfan was achieved at an absorbed dose of 1020 Gy. The removal of endosulfan by gamma-rays irradiation was influenced by an absorbed dose and significantly increased in the presence of aqueous electron (eaq-). However, efficiency of the process was inhibited in the presence of eaq- scavengers, such as N2O, NO3-, acid, and Fe3+. The observed dose constant decreased while radiation yield (G-value) increased with increasing initial concentrations of the target contaminant and decreasing dose-rate. The removal efficiency of endosulfan II was lower than endosulfan I. The degradation mechanism of endosulfan by the AORPs was proposed showing that reductive pathways involving eaq- started at the chlorine attached to the ring while oxidative pathway was initiated due to attack of hydroxyl radical at the SO bond. The mass balance showed 95% loss of chloride from endosulfan at an absorbed dose of 1020 Gy. The formation of chloride and acetate suggest that gamma irradiation based AORPs are potential methods for the removal of endosulfan and its by-products from contaminated water. [ABSTRACT FROM AUTHOR]

This study reported Fe doped zinc oxide (Fe-ZnO) synthesis to degrade chlorpyrifos (CPY), a highly toxic organophosphate pesticide and important sources of agricultural wastes. Fourier transform infrared, X-ray diffraction, scanning electron microscope, and energy-dispersive X-ray spectroscopic analyses showed successful formation of the Fe-ZnO with highly crystalline and amorphous nature. Water collected from agricultural wastes were treated with Fe-ZnO and the results showed 67% degradation of CPY by Fe-ZnO versus 39% by ZnO at 140 min treatment time. Detail mechanism involving reactive oxygen species production from solar light activated Fe-ZnO and their role in degradation of CPY was assessed. Use of H 2 O 2 , peroxydisulfate (S 2 O 8 2−) and peroxymonosulfate (HSO 5 −) with Fe-ZnO under solar irradiation promoted removal of CPY. The peroxides yielded hydroxyl (OH) and sulfate radical (▪) under solar irradiation mediated by Fe-ZnO. Effects of several parameters including concentration of pollutant and oxidants, pH, co-existing ions, and presence of natural organic matter on CPY degradation were studied. Among peroxides, HSO 5 − revealed to provide better performance. The prepared Fe-ZnO showed high reusability and greater mineralization of CPY. The GC-MS analysis showed degradation of CPY resulted into several transformation products (TPs). Toxicity analysis of CPY as well as its TPs was performed and the formation of non-toxic acetate imply greater capability of the treatment technology. [Display omitted] • Fe doped ZnO was successfully synthesized by sol-gel method. • Fe doping and use of peroxides synergistically promoted performance of ZnO. • Degradation of chlorpyrifos was inhibited by h vb + and OH scavengers. • Second-order rate constants of chlorpyrifos with OH and ▪ were calculated. • Toxicities of chlorpyrifos and its transformation products were estimated. [ABSTRACT FROM AUTHOR]

In this study, biochar was prepared from Sidr plant leaves and used for the treatment of ciprofloxacin (CIP)-contaminated water. CIP is important class of emerging water pollutants from pharmaceutical industries. The biochar showed 65% adsorption efficiency and 43.48 mg/g adsorption capacity of CIP. Adsorption efficiency as well as adsorption capacity were improved to 91% and 62.50 mg/g, respectively, by phosphoric acid (H3PO4) modified biochar. Removal of CIP by the prepared biochar was due to different surface functional groups of CIP and biochar as revealed from the study of different characterization analyses. The presence of PO43– group in modified biochar led to maximum binding of CIP. Also, the modified biochar showed higher reusability potential and less leaching of ions when compared to the raw biochar. Removal of CIP was affected by concentrations of CIP, the amount of biochar and different pH's; the maximum removal of CIP was achieved at pH 4. The Freundlich and pseudo-first-order models best fitted the removal of CIP by modified biochar. Advanced characterization techniques were applied to investigate surface and physiological characteristics of the biochar and modified biochar. The modification showed high impact on the performance and stability of biochar. The study showed significant impacts of modification on the potential of the biochar for treatment of CIP-contaminated water. [ABSTRACT FROM AUTHOR]

• The nZVMn/PBC showed high activity in adsorptive and oxidative removal of Congo-red. • The physical properties of biochar were improved with the coupling of nZVMn. • The nZVMn/PBC-catalyzed H2O2 into ●OH that caused oxidative removal of Congo-red. • Congo-red removal was promoted with the high dose of adsorbent and H2O2. • Degradation pathways of Congo-red in ●OH-mediated oxidative system were proposed. Congo-red (CR), a precursor of textile products and a contaminant of great concern, has contaminated aquatic environments. Here, we explored the synthesis of mesoporous nano-zerovalent manganese (nZVMn) and Phoenix dactylifera leaves biochar (PBC) composite for the removal of CR from water. The nZVMn/PBC adsorbed 117.647 mg/g of CR versus 25.316 mg/g by PBC at [CR] 0 = 20 mg/L and [PBC] 0 = [nZVMn/PBC] 0 = 500 mg/L. Variation of [nZVMn/PBC] 0 , [CR] 0 and pH influenced the adsorption of CR. Freundlich adsorption isotherm and pseudo-first-order kinetic models best fitted CR adsorption. The H 2 O 2 coupling with nZVMn/PBC promoted removal of CR possibly due to the formation of hydroxyl radical (●OH) and caused 95 % removal of CR versus 77 % by nZVMn/PBC alone. The ●OH scavengers inhibited the removal of CR. The nZVMn/PBC showed a good reusability and efficient removal of CR up to the seventh cycle of treatment. Results reveal that nZVMn improved performance, thermal stability and reusability of biochar. Degradation products from ●OH-mediated degradation of CR were studied by ultraperformance liquid chromatography with mass spectrometric detector to establish degradation pathways. The ion-chromatographic analysis showed the formation of non-toxic inorganic acetate product, which suggests high potential of the newly fabricated adsorbent in the removal of CR. [ABSTRACT FROM AUTHOR]

• Deep eutectic solvent and nitrogen-doping enhanced stability and efficiency of Ceria. • Removal of sulfamethaxazole was inhibited in the presence of h vb + and OH scavengers. • Second-order rate constant of sulfamethaxazole with OH was calculated. • Degradation pathways were established and estimated toxicities of SMX and its DPs. • Ceria NPs were highly active against Gram-positive and Gram-negative bacteria. In this study, highly crystalline, mesoporous, small sized, stable, and efficient nitrogen-doped (N-doped) Ceria nanoparticles were synthesized using deep eutectic solvent (DES) and used for the photocatalytic degradation of sulfamethaxazole (SMX), a widely used human medication and emerging water contaminant. The N-doped Ceria resulted in 96% removal of SMX versus 59% by Ceria under solar irradiation at 150 min time using [SMX] 0 = 10 mg/L and [Ceria] 0 = [N-doped Ceria] 0 = 0.5 g/L. The solar irradiation of the photocatalysts produced OH which was proved with electron spin resonance (ESR) spectroscopy and radical scavenger studies and the resulting OH caused the degradation of SMX. The OH showed high second-order rate constant with SMX, e.g., 4.9 × 109 M−1 s−1. The photocatalytic degradation of SMX was influenced by pH, concentrations of SMX and photocatalysts, inorganic anions, and natural organic matter. The kinetics of the photocatalytic degradation of SMX was found to be pseudo-first-order. The SMX degradation resulted into several products which were identified by UPLC-MS/MS and the resulting products were used to establish degradation pathways of SMX. The synthesized Ceria and N-doped Ceria also showed good antimicrobial activities towards Staphylococcus aureus and Escherichia coli. The treatment of SMX showed high reusability of N-doped Ceria, low leaching of cerium ions into reaction solution, and high decline in toxicity of SMX which suggests high potential of the synthesized nanoparticles towards SMX degradation. [ABSTRACT FROM AUTHOR]

• Congo-red dye and its DPs were found highly toxic. • Gamma-ray with the added H 2 O 2 and S 2 O 8 2− efficiently degraded CR. • Reactivity of congo-red dye with OH and SO 4 − were calculated. • Proposed degradation pathways of CR were developed from the DPs evolved. Gamma radiation has received increasing attention due to their high potential in degradation of recalcitrant pollutants. Thus in the present study, gamma radiation was used for degradation of congo-red (CR) dye, a highly toxic and carcinogenic pollutant, in the presence of H 2 O 2 and S 2 O 8 2−. The CR was significantly degraded by gamma radiation (i.e., 53%), however, presence of H 2 O 2 and S 2 O 8 2− promoted degradation of CR to 98 and 87%, respectively, at 1184 Gy absorbed dose. The radical scavengers and electron spin resonance studies revealed that gamma radiation decompose H 2 O 2 and S 2 O 8 2− into OH and SO 4 − and both OH and SO 4 − caused degradation of CR. The CR showed high reactivity, i.e., 3.25 × 109 and 8.50 × 108 M−1 s−1 with OH and SO 4 −, respectively, and removal of CR was inhibited in the presence of OH and SO 4 − scavengers. The removal of CR was promoted with elevating initial concentrations of H 2 O 2 and S 2 O 8 2− and decreasing initial concentrations of CR. pH of aqueous solution also significantly influenced removal of the dye. The proposed degradation pathways of CR were established from the OH mediated degradation of CR and nature of identified degradation products. The greater mineralization of CR, formation of small molecular mass degradation product, and decline in concentration of acetate after extended treatment suggest the gamma-ray mediated peroxide based process to be a promising alternative for potential degradation of CR. [ABSTRACT FROM AUTHOR]

Chlorpyrifos (CPY), an organophosphate pesticide is largely used throughout the world on different crops for the control of pests and causes severe health and environmental issues. In this study, highly efficient, crystalline, and nm-rang sized zerovalent zinc (nZVZn) catalyst was synthesized and used for removal of chlorpyrifos at semi-pilot scale. The nZVZn showed high activity and caused 55% removal of CPY at 90 min time under the conditions of [CPY] 0 = 10 mg/L, [nZVZn] 0 = 1.0 g/L, and flow rate of the reactor = 0.2 L/min. Using identical conditions of [CPY] 0 , [nZVZn] 0 and flow rate, the use of peroxymonosulfate (PMS) promoted the performance of nZVZn and caused 99.5% removal of CPY at [PMS] 0 = 40 mg/L. The electron spin resonance (ESR) spectroscopy studies revealed that nZVZn catalyzed PMS reactions yield hydroxyl and sulfate radicals that degraded CPY and removal of CPY was suppressed by applying radical scavengers. The nZVZn catalyzed PMS based removal of CPY was optimum at high [PMS] 0 , [nZVZn] 0 and low pH of solution. The flow rate of the pilot plant reactor also influenced the degradation efficiency of CPY. High pH of solution, high [CPY] 0 as well as use of alcohols, NOM, and some inorganic ions inhibited removal of CPY by nZVZn catalyzed PMS. The analysis of degradation products (DPs) of CPY were used to propose degradation pathways of CPY. The high TOC removal of CPY, low leaching of Zn2+ from Zn0 into aqueous solution, and toxicity reduction of CPY suggest the nZVZn catalyzed PMS process to be highly effective and environmental benign for treatment of CPY. Image 1 • Nano zerovalent zinc was used for removal of chlorpyrifos at semi-pilot scale. • Removal of chlorpyrifos by zerovalent zinc was promoted by peroxymonosulfate. • Hydroxyl and sulfate radical rate constants with chlorpyrifos were calculated. • Proposed degradation pathways of chlorpyrifos were suggested. • Toxicities of treated chlorpyrifos solutions and zinc ion leaching were evaluated. [ABSTRACT FROM AUTHOR]

Abstract In the present study the synthesis of an inexpensive solar light responsive Co2+ and Fe3+ co-doped TiO 2 (Co Fe TiO 2) for efficient photocatalytic degradation of ofloxacin (OFL) in addition to its excellent activity as peroxidase mimics has been reported. The as-synthesized material was fully investigated morphologically and structurally by X-ray diffraction (XRD) analysis, field emission-scanning electron microscopy (FE-SEM), Fourier transform infrared (FTIR) and UV diffuse reflectance spectroscopy (UV-DRS). The morphology of the as-synthesized Co Fe TiO 2 appeared to be more dispersed, porous and uniform. The UV-DRS analysis showed that the band gap of the as-synthesized TiO 2 , Fe TiO 2 , Co TiO 2 , Co Fe TiO 2 was measured as 3.31, 3.22, 3.15 and 3.04 eV, respectively. The pilot scale experiments were conducted in a simple non-concentrating solar photoreactor by using the as-synthesized Co Fe TiO 2 having total volume of 5 L. To synergize the photocatalytic process the photocatalytic reactor was added with peroxymonosulfate (HSO 5 −). The effect of various process parameters like [HSO 5 −] 0 , flow rate and [Co Fe TiO 2 ] 0 were optimized. The assessment of degradation products (DPs) of OFL and then their toxicity analysis suggested the as-synthesized Co Fe TiO 2 provides a safe route for the solar light induced photocatalytic degradation of OFL. The as-synthesized Co-Fe TiO 2 was also applied as novel peroxidase mimetic that can catalyze 3,3′,5,5′-tetramethylbenzidine (TMB) when H 2 O 2 serves as oxidant. The results showed that the color response and the peroxidase like response of Co Fe TiO 2 highly rely on the concentration of H 2 O 2 and thus the as-synthesized material can successfully be applied for the calorimetric sensing of H 2 O 2. Graphical abstract Unlabelled Image Highlights • Solar light driven photocatalysis of ofloxacin at pilot scale level. • Lowering the band gap of TiO 2 by co-doping with Co2+ and Fe3+. • Fifteen (15) new photocatalytic degradation byproducts of OFL were found. • Toxicity assessment revealed that some of the DPs are more toxic than OFL. • In situ peroxidase like behavior of Co Fe TiO 2 was found. [ABSTRACT FROM AUTHOR]

Abstract This study presents the synthesis of a novel Mn2+ and Co2+ co-doped TiO 2 (Mn-Co-TiO 2) for the photocatalytic degradation of enoxacin (ENX) under solar light irradiation. The as-synthesized photocatalysts were fully characterized by X-ray diffraction (XRD) analysis, field emission-scanning electron microscopy (FE-SEM), and UV-diffuse reflectance spectroscopy (UV-DRS). The structural appearance of the Mn-Co-TiO 2 suggests porous cylindrical type morphology. Moreover, the co-doping of Mn2+ and Co2+ has successfully reduced the band gap of TiO 2 from 2.81 eV to 2.10 eV. Applying Langmuir Hinshelwood kinetic model, the photocatalytic degradation of ENX by Mn-Co-TiO 2 followed pseudo-first-order kinetics. A total of twelve (12) DPs of ENX were identified by UPLC/MS-MS. The natural water constituents such as CO 3 2−, HCO 3 −, Cl− and Fe3+ had great influence on the photocatalytic degradation of ENX by Mn-Co-TiO 2 under solar light irradiation. The as-synthesized Mn-Co-TiO 2 showed appreciable results for the photocatalytic degradation of ENX in synthetic wastewater (SWW) and real wastewater (RWW) samples. Furthermore, the toxicity assessment of ENX and its DPs towards aquatic organisms (i.e., fish, daphnia and green algae) was measured which are helpful for the practical implementation of this technology for wastewater treatment. The Mn-Co-TiO 2 materials also showed good peroxidase-like activity towards the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) in the presence of H 2 O 2 and followed Michaelis-Menten kinetics. Graphical abstract Unlabelled Image Highlights • Efficient Solar light driven photocatalysis of Enoxacin. • Narrowing the band gap of TiO 2 by co-doping with Mn2+ and Co2+ • Total of twelve (12) new photocatalytic degradation byproducts of ENX were found. • Toxicity assessment revealed that some of the degradation byproducts are more toxic than ENX. • Additional peroxidase like activity of Mn/Co-TiO 2 was found. [ABSTRACT FROM AUTHOR]

The removal of brilliant green (BG), a toxic organic and cationic dye, has been examined by UV/S 2 O 8 2− (PS), UV/HSO 5 − (PMS) and UV/H 2 O 2 processes. BG showed insignificant direct photolysis at 254 nm (i.e., 8.6% after 30 min). However, enhanced BG degradation was observed in UV/PS, UV/PMS and UV/H 2 O 2 systems as revealed from 63.1, 47.0 and 34.8% BG degradation, respectively, at 30 min of reaction time, using 0.05 mM BG and 1.0 mM oxidant initial concentration. The bimolecular rate constants of OH and SO 4 − with BG were determined to be 2.35 × 10 9 and 2.21 × 10 9 M −1 s −1 , respectively. Electrical energy per order (EE/O) values for UV/PS, UV/PMS and UV/H 2 O 2 processes were calculated to be 5.4, 6.8, and 7.8 KWh/m 3 /order, respectively. The addition of humic acid (HA) and inorganic anions inhibited the degradation of BG by UV/PS in the order of NO 2 −  > HA > HCO 3 −  > Cl −   > NO 3 −  ≈ SO 4 2− . The results of frontier electron densities (FEDs) showed that C-atom holding the three rings (C7), and C-atoms at para positions to N-alkyl groups of the two rings (C4 and C14) are the predominant sites for radical addition. Furthermore, nine degradation products (DPs) of BG were detected experimentally using LC/MS/MS. [ABSTRACT FROM AUTHOR]

Carbamazepine (CBZ), a widely used antiepileptic drug, was removed by UV–254 nm based advanced oxidation processes. CBZ was found to be stable under sole UV, however, removal of CBZ was promoted using Fe3+ and Fe2+ with UV. Further, removal efficiency of CBZ was significantly enhanced by coupling H2O2 with UV and Fe3+/Fe2+. At 3600 mJ cm−2, 7.5, 60.2, 74.3 and 90.6% CBZ degradation was achieved in UV, UV/H2O2, UV/H2O2/Fe3+ and UV/H2O2/Fe2+, using CBZ, H2O2, Fe2+ and Fe3+ at 21.16, 1060.00, 17.91 and 17.91 μM, respectively. Higher CBZ degradation in the presence of H2O2 was attributed to HO whose second-order rate constant with CBZ was calculated to be (8.83 ± 0.27) × 109 M−1 s−1. Removal of CBZ by UV/H2O2/Fe2+ system was optimum at pH 3.0, as 80.8, 90.6 and 70.4% CBZ degradation was observed at pH 2.0, 3.0 and 6.5, respectively. The removal of CBZ by UV/H2O2/Fe2+ was retarded in the presence of Cl− and humic acid as revealed from 84.5 and 56.7% CBZ degradation in the presence of Cl− and humic acid, respectively, compared to 90.6% in their absence at 3600 mJ cm−2. The CBZ degradation products were found to be less toxic than the parent compound, suggesting important role of UV-assisted AOPs in efficient removal and toxicity reduction of CBZ and their degradation products. [ABSTRACT FROM AUTHOR]

• Degradation of carbamazepine was investigated in UV-assisted AOPs. • Carbamazepine was recalcitrant to sole UV but susceptible to UV/H 2 O 2 /Fe2+ oxidation. • Second order rate constant of carbamazepine with OH was (8.83 ± 0.27) × 109 M−1 s−1. • The UV/H 2 O 2 /Fe2+ treatment was efficient in toxicity reduction of CBZ. • Degradation mechanism was proposed from identified degradation products. Carbamazepine (CBZ), a widely used antiepileptic drug, was removed by UV–254 nm based advanced oxidation processes. CBZ was found to be stable under sole UV, however, removal of CBZ was promoted using Fe3+ and Fe2+ with UV. Further, removal efficiency of CBZ was significantly enhanced by coupling H 2 O 2 with UV and Fe3+/Fe2+. At 3600 mJ cm−2, 7.5, 60.2, 74.3 and 90.6% CBZ degradation was achieved in UV, UV/H 2 O 2 , UV/H 2 O 2 /Fe3+ and UV/H 2 O 2 /Fe2+, using CBZ, H 2 O 2 , Fe2+ and Fe3+ at 21.16, 1060.00, 17.91 and 17.91 μM, respectively. Higher CBZ degradation in the presence of H 2 O 2 was attributed to HO whose second-order rate constant with CBZ was calculated to be (8.83 ± 0.27) × 109 M−1 s−1. Removal of CBZ by UV/H 2 O 2 /Fe2+ system was optimum at pH 3.0, as 80.8, 90.6 and 70.4% CBZ degradation was observed at pH 2.0, 3.0 and 6.5, respectively. The removal of CBZ by UV/H 2 O 2 /Fe2+ was retarded in the presence of Cl− and humic acid as revealed from 84.5 and 56.7% CBZ degradation in the presence of Cl− and humic acid, respectively, compared to 90.6% in their absence at 3600 mJ cm−2. The CBZ degradation products were found to be less toxic than the parent compound, suggesting important role of UV-assisted AOPs in efficient removal and toxicity reduction of CBZ and their degradation products. [ABSTRACT FROM AUTHOR]

Desethyl-atrazine (DEA) and desisopropyl-atrazine (DIA) are the two major degradation by-products of atrazine (a suspected human carcinogen and endocrine disrupting herbicide), and show an equal toxicity to their parent compound. This study investigated the degradation of DEA and DIA with OH and SO 4 − generated from the activation of peroxides, i.e., persulfate (S 2 O 8 2− ), peroxymonosulfate (HSO 5 − ) and hydrogen peroxide (H 2 O 2 ), by UV-254 nm radiation in the presence or absence of Fe 2+ . Quantum yields of DEA and DIA were independent of pH (3.0–11.0). The higher quantum yield of reactive radicals from UV/S 2 O 8 2− , i.e., 1.8 compared to 1.04 for UV/HSO 5 − and 1.0 for UV/H 2 O 2 , resulted in greater efficiency of UV/S 2 O 8 2− for both DEA and DIA degradation. The second-order rate constants of DEA and DIA with SO 4 − were calculated to be (6.42 ± 0.12) × 10 8 and (1.70 ± 0.30) × 10 9 M −1 s −1 , and that with OH were (1.14 ± 0.09) × 10 9 and (2.22 ± 0.44) × 10 9 M −1 s −1 , respectively, suggesting a strong impact of side chains toward radical reactions. Fe 2+ promoted slightly the activation of the examined peroxides at pH 7.4. Presence of organic matter and alkalinity in field water samples negatively influenced the efficiency of UV/S 2 O 8 2− . Based on the identified degradation by-products by GC–MS, potential degradation pathways were proposed for both compounds. The results obtained suggested that DEA and DIA can be efficiently removed from the contaminated water by OH and SO 4 − based-AOPs. [ABSTRACT FROM AUTHOR]

[Display omitted] • Synergistic HC/SPC/O 3 process for degradation of emerging environmental pollutants. • Superior performance of HC/SPC/O 3 comparing to HC/H 2 O 2 /O 3. • Improvement of sustainability and process safety of AOPs by percarbonate oxidant. • Green advanced oxidation based on cavitation phenomenon. • Importance of hydrodynamic cavitation in activation of oxidants. Hydrodynamic cavitation (HC) was employed to activate sodium percarbonate (SPC) and ozone (O 3) to degrade recalcitrant 1,4-dioxane. The degradation efficiency > 99 % with a rate constant of 4.04 × 10−2 min−1 was achieved in 120 min under the optimal conditions of cavitation number (C v) 0.27, pH 5, molar ratio of oxidant to pollutant (r ox) 8, ozone dose of 0.86 g h−1 under 25 ± 2 °C with initial concentration of 1,4-dioxane 100 ppm. The application of HC with SPC/O 3 increased the degradation efficiency by 43.32 % in 120 min, confirming a synergistic effect between the coupled processes. In addition, the degradation efficiency of 1,4-dioxane in HC/SPC/O 3 was superior as compared to HC/H 2 O 2 /O 3 , suggesting that the presence of SPC has a significant role in degradation of 1,4-dioxane. Radical quenching experiment revealed highest contribution of hydroxyl (HO) radicals in the degradation of 1,4-dioxane among carbonate (CO 3 −) and superoxide (O 2 −) radicals. The presence of co-existing anions resulted in an inhibitory effect in the following order: SO 4 2− > NO 3 − > Cl−. Based on GC–MS analysis, ethylene glycol diformate (EGDF) was detected as the main degradation product of 1,4-dioxane. The observed intermediate supports the radical route of 1,4-dioxane oxidation, which involves H-abstraction, ΔC-C splitting at the α-C position, subsequent dimerization, fragmentation and mineralization. Electric energy per order (E EO) for best process was 102.65 kWh·m−3·order−1. Total cost of treatment was estimated as approx. 12 USD/m3. These findings confirmed the SPC as an efficient, environmentally-friendly alternative to H 2 O 2 and broadened the scope of HC-based AOPs for water and wastewater treatment. [ABSTRACT FROM AUTHOR]

Highlights: [•] Degradation of atrazine was investigated in UV, UV/H2O2, UV/HSO5 − and UV/S2O8 2− AOPs. [•] UV/S2O8 2− process was found to be more efficient as well as more economical. [•] The pH affected UV/S2O8 2− but had no significant influence on UV, UV/H2O2 and UV/HSO5 −. [•] Second order rate constants of atrazine with SO4 − and OH were found to be comparable. [•] Degradation mechanism was investigated by GC–MS and LC–MS/MS analysis. [ABSTRACT FROM AUTHOR]

Conventional titanium dioxide (TiO2) materials can be activated only by ultraviolet (UV) light, which is only 4-5% of the whole solar spectrum. As a result, visible light (vis)-active TiO2-based photocatalysts have recently received significant attention in the field of TiO2 photocatalytic treatment and purification of water and air. This study reports the preparation of UV-visible light-active phosphorous (P)-doped, fluorine (F)-doped, and PF-co-doped anatase TiO2 nanoparticles via an innovative sol-gel method. Prepared nanoparticles were characterized by UV-vis diffuse reflectance spectroscopy, X-ray diffraction analysis, Raman spectroscopy, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy (FTIR), and porosimetry analysis. Synthesized materials exhibited improved structural properties, including high surface area, small crystallite size, reduced band gap energy, mesoporous structure, and high porosity. Due to doping with P and F, light absorption of TiO2 in the visible light region was efficiently enhanced with effective band gap energy of 2.70 eV. Brunauer-Emmett-Teller (BET) surface area for PF-co-doped, P-doped, F-doped, and reference TiO2 nanoparticles was 212.0, 175.0, 88.8, and 79.7 m2/g, respectively. PF-co-doped TiO2 showed the highest photocatalytic degradation of atrazine, which could be attributed to the beneficial effects including small crystallite size, high BET surface area, and light absorption in UV-visible region, induced by co-doping of TiO2 with P and F. Finally, reaction intermediates were determined, which confirms the photocatalytic degradation of atrazine using the synthesized catalysts under UV-visible light illumination. [ABSTRACT FROM AUTHOR]

[Display omitted] • Unexpected nitration processes led to formation of several nitro-derivatives. • Nitrogen fixation importantly contributes to formation of reactive nitrogen species in sonolysis. • Denitration and renitration processes in persulfate based AOPs causes nitration of intermediates. • Post-treatment and nitro-derivatives monitoring are important in AOPs. • Risk of low water quality in case of unexpected nitration during treatment process. Chemical compounds containing nitro group (nitro-products) are a one of toxic by-products, that can be formed during wastewater treatment processes. In case of presence of nitrite or nitrate ions, the formation of nitro-products during advanced oxidation processes (AOPs) is very common. It is caused by the reactive nitrogen species (RNs) such as nitrate radical (NO 3 •), nitrite radical (NO 2 •), nitrogen oxide radical (NO•) and peroxynirite (ONOO–). In fact, the oxidative degradation of N-containing pollutants releases nitrate, nitrite and ammonium ions. In some cases, secondary reactions of mineralised nitrogen species (nitrate and nitrite ions) with the parent or intermediate compound generate next several nitro-products. The nitro-products are more toxic comparing to the primary pollutants and act as the precursors of the nitrogenous disinfection by-products. Moreover, some studies reported unexpected nitro-products formation during the oxidative degradation. In case of such processes a special attention should be made to monitor and minimize these effects. De-nitration of the initial nitro-compounds induces the formation of various nitro-products in AOPs. It was observed for UV light driven, Fenton and persulfate based AOPs. The sonochemical nitrogen fixation is a key mechanism for the formation of nitro-compounds in ultrasounds based AOPs. Therefore, this paper is focused on comparison of various AOPs in terms of nitro-products formation mechanisms and the associated environmental issues. [ABSTRACT FROM AUTHOR]

• Eosin modified TiO 2 film with co-exposed {001} and {101} facets was synthesized. • Sulfite/Eosin-TiO 2 system was used as SO 4 − based Advanced Oxidation Process. • Degradation of PABA was performed by sulfite/Eosin-TiO 2 /solar system. • Under visible light irradiation, Eosin-TiO 2 showed appreciable H 2 production rate. • Solar/Eosin-TiO 2 (/SO 3 2–) is a promising method for environmental sustainability. Owing to the increasing photosensitivity and DNA damage properties of para -aminobenzoic acid (PABA), concerns have been raised over the exposure of humans to PABA. Solar light-driven photocatalysis (SPC) provides a promising solution for the effective removal of organic pollutants especially when directed towards sulfate radical (SO 4 −) production. Herein, we have developed a sulfite-enhanced SPC using Eosin-Y sensitized TiO 2 /Ti film as a photocatalyst. The removal efficiency of PABA was enhanced by coupling Eosin-Y with TiO 2 /Ti film as revealed from 23.6 and 48.9 % PABA degradation by reference-TiO 2 /solar and Eosin-TiO 2 /solar, respectively. The apparent rate constant of PABA degradation by Eosin-TiO 2 was improved by 4.7 times in presence of 5 mM sulfite. Interestingly, Eosin-TiO 2 showed appreciable H 2 production rate under visible light illumination. Solar/sulfite/Eosin-TiO 2 system is a promising technology for environmental sustainability by using the renewable solar energy and air pollutants since sulfite is a waste from flue gas desulfurization process. [ABSTRACT FROM AUTHOR]

• Highly stable and solar light responsive Bi-TiO 2 was synthesized. • The doping of Bi3+ induced Ti3+ and oxygen vacancy in the TiO 2 lattice. • The photocatalytic efficiency of TBi5 was enhanced by coupling with HSO 5 −. • SO 4 − and OH were dominant species involved in the degradation of FLU. • The contribution rate of SO 4 − was calculated to be 89% in the degradation of FLU. The present study is focused on the synthesis of a novel solar light responsive bismuth doped titania (Bi-TiO 2) through a facile so-gel technique by applying various wt% of Bi. The as-synthesized Bi-TiO 2 showed superior photocatalytic performance than un-doped TiO 2 towards degradation of flumequine (FLU) under solar light irradiation. The as-synthesized material was thoroughly characterized to examine its structure, morphology and chemical states. The EPR analysis revealed the existence of Ti3+ ion and oxygen vacancy, which is created due to Bi-doping. The as-synthesized Bi-TiO 2 with 5 wt% Bi (TBi5) showed excellent photocatalytic performance as compared to their counterparts. The photocatalytic activity of TBi5 was further improved when added with peroxymonosulfate (HSO 5 −) and increased with increasing [HSO 5 −] 0. The mechanistic investigation and radical scavenging studies revealed that OH and SO 4 − are involved in the degradation of FLU by the as-synthesized material. The bimolecular rate constants of OH and SO 4 − were calculated to be 9.1 × 109 M−1s−1 and 8.5 × 109 M−1s−1, respectively. The photocatalytic performance of the as-synthesized TBi5 coupled with HSO 5 − under solar light irradiation towards degradation of FLU in Milli-Q water (MW), tape water (TW) and synthetic wastewater (SWW) was 92, 82 and 70% with k app values of 0.093, 0.085 and 0.066 min−1, respectively. Furthermore, the degradation pathways of FLU were predicted on the basis of its degradation products (DPs). The high mineralization of FLU as well as the evaluation of non-toxic DPs suggests that solar light/TBi5/HSO 5 − is a promising advanced oxidation process for the future wastewater treatment applications. [ABSTRACT FROM AUTHOR]

In this study, a stable ionic liquid (IL) mediated zero‐valent copper nanoparticle (nZVCu), namely IL‐nZVCu, has been evaluated for catalytic properties towards H2O2‐mediated TMB (3, 3',5,5'‐tetramethylbenzidine) reaction under normal conditions of temperature and pH. The various analytical techniques like Fourier Transform Infrared Spectroscopy (FT‐IR), UV–Vis diffuse reflectance spectroscopy (UV‐Vis DRS), X‐ray powder diffraction (XRD), scanning electron microscope (SEM), Transmission electron microscopy (TEM) and X‐ray photoelectron spectroscopy (XPS) were used to confirm the structure and nano size of nZVCu. The simple protic IL 1‐hydrogen‐3‐methylimidazolium acetate (HmimOAc) with its cation 1‐methylimidazole and anion acetate was synthesized, characterized, and coated on nZVCu to prepared IL‐nZVCu. As a novel mimic peroxidase, IL‐nZVCu could quickly catalyze the oxidation reaction of specific chromogenic substrate TMB, when H2O2 acts as an oxidant, followed by a remarkable color change in the solution measured by UV/Vis Spectrophotometry. The enhanced catalytic activity and significant color change were greatly dependent on the catalyst dosage, the volume of IL taken, incubation time, H2O2 concentration, and TMB concentration. Also, IL‐nZVCu showed no response toward ascorbic acid, cholesterol, dopamine, urea and uric acid. Based on these findings, IL‐nZVCu could be effectively used for visual colorimetric sensing of H2O2 with a limit of detection (LOD) of 44 μM over the dynamic linear range from 40 μM to 1000 μM concentration. [ABSTRACT FROM AUTHOR]

In the current investigation, a new insight into the adsorptive interaction of iron–silicon mixed oxide with arsenate was proposed through comparative studying the behavior of arsenate on the mixed oxide and on the parent oxides, i.e., iron hydroxide and silica. All the oxides were characterized by using different physiochemical methods. The arsenate concentration, pH, temperature, co-ion effect, and calcination of adsorbents were the key parameters of this investigation. The Langmuir model was used for the interpretation of the adsorption data. The thermodynamic parameters and spectroscopic evidences of the samples before and after arsenate adsorption confirmed that the mechanisms of arsenate adsorption by Fe(OH)3 and mixed oxide showed close similarity. [ABSTRACT FROM AUTHOR]

[Display omitted] • Nanocomposites of siltstone were prepared for Cr decontamination from water. • The composite BSS/FeO/ZnO showed better efficiency for Cr removal (87%). • Langmuir and pseudo-second-order kinetic models well explained Cr adsorption. • The BSS/ZnO, BSS/FeO, and BSS/ZnO/FeO showed excellent reusability and stability. • Difference in Cr removal was confirmed with characterization of the adsorbents. In this study, nanocomposites of Baghanwala Siltstone (BSS) with ZnO (BSS/ZnO), FeO (BSS/FeO), and BSS/ZnO/FeO were successfully prepared for the removal of hexavalent chromium [(Cr (VI)] from aqueous solutions via a batch adsorption process. The characterization studies by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy-energy-dispersive X-ray spectroscopy (SEM-EDX) found successful synthesis of the composites and demonstrated the occurrence of different active functional groups that played an active role in Cr ion adsorption. The effect of Cr initial concentrations (25–100 mg/L), adsorbent dose (0.5–2 g/L), pH (2–8), and contact time (0–160 min) on Cr remediation from contaminated water was examined. The order of Cr ion removal was BSS/ZnO/FeO (77–87%) > BSS/ZnO (74–83%) > BSS/FeO (71–77%) > BSS (68–74%). The as-synthesized BSS/ZnO/FeO led to successful Cr removal (87%) at a 25 mg/L Cr concentration at pH 4.0. The Cr ion adsorption by the BSS/ZnO/FeO nanocomposite was well explained by the Langmuir adsorption isotherm model (R2 > 0.99), while the kinetic experimental data was well fitted with the pseudo-second-order model (R2 > 0.99). Among the as-synthesized adsorbents, the BSS/ZnO/FeO nanocomposite showed excellent stability and reusability in seven sorption cycles. The results showed that the as-synthesized BSS/ZnO/FeO nanocomposite had the greatest adsorption potential for removing Cr ions from contaminated water. [ABSTRACT FROM AUTHOR]

The present study was conducted to explore arsenic (As) tolerance and phytostabilization potential of the two tree species, buttonwood (Conocarpus erectus) and eastern cottonwood (Populus deltoides). Both plant species were grown in pots and were exposed to various soil As levels (control, 5, 10, 15, and 20 mg kg−1). The plants were harvested after 9 months for the evaluation of growth parameters as well as root and shoot As concentrations. With increasing soil As levels, plant height stress tolerance index (PHSTI) was significantly decreased in both tree species, whereas root length stress tolerance index (RLSTI) and dry matter stress tolerance index (DMSTI) were not affected. Root and shoot As concentrations significantly increased in both tree species with increasing soil As levels. Translocation factor and bioconcentration factor were less than 1.0 for both plant species. This study revealed that both tree species are non-hyperaccumulators of As, but they could be used for phytostabilization of As-contaminated soils. [ABSTRACT FROM AUTHOR]

Synthesis of Nobel metal nanoparticles, play a key role in the field of medicine. Plants contain a substantial number of organic constituents, like phenolic compounds and various types of glycosides that help in synthesis of metal nanoparticles. Synthesis of metal nanoparticles by green method is one of the best and environment friendly methods. The major significance of the green synthesis is lack of toxic by-products produced during metal nanoparticle synthesis. The nanoparticles, synthesized by green method show various significant biological activities. Most of the research articles report the synthesized nanoparticles to be active against gram positive and gram negative bacteria. Some of these bacteria include Escherichia coli , Bacillus subtilis , Klebsiella pneumonia and Pseudomonas fluorescens . The synthesized nanoparticles also show significant antifungal activity against Trichophyton simii , Trichophyton mentagrophytes and Trichophyton rubrum as well as different types of cancer cells such as breast cancer cell line. They also exhibit significant antioxidant activity. The activities of these Nobel metal nano-particles mainly depend on the size and shape. The particles of small size with large surface area show good activity in the field of medicine. The synthesized nanoparticles are also active against leishmanial diseases. This research article explores in detail the green synthesis of the nanoparticles and their uses thereof. [ABSTRACT FROM AUTHOR]

[Display omitted] • Green approaches are promising to conventional synthesis techniques. • NPs with < 60 nm in size are obtainable. • Plant mediated synthesis is superior to the microorganism mediated synthesis. • Titanium dioxide nanoparticles as catalysts and catalytic support in biodiesel production are reviewed. • Recovery and stability of TiO 2 based nanocatalysts require special attention. • Use of solar energy for biodiesel production is a technical challenge. Biodiesel is a strategic measure to mitigate greenhouse gas emissions and other negative environmental impacts in line with oxidation of fossil fuels. Alkali-catalysed transesterification is the conventional production protocols in biodiesel production due to its technical reliability in line with low maintenance cost. Nonetheless, alkali-catalysed biodiesel production required to use the refined lipid feedstock due to low tolerance against impurities. TiO 2 NPs have been widely employed as heterogeneous catalysts. Also, the use of TiO 2 NPs could be beneficial because TiO 2 adaptation in production of biodiesel could combine transesterification and esterification into a single process. Nonetheless, the general protocol in TiO 2 NPs synthesis could not circumvent to use hazardous/toxic chemicals leading to serious/acute health and environmental problems. Several studies have demonstrated that green synthesis of TiO 2 NPs using microorganisms and plants as alternate approaches can eliminate the problems associated with conventional methods without sacrificing the exceptional features of these nano materials. Hence, the main objective of this review is to offer fundamental insights and recent advances in green methods for producing TiO 2 NPs driven by various microorganisms and plants extract along with quick summary of physio-chemical methods. In particular, the TiO 2 NPs with reduced sizes (<60 nm) are possible to obtain using cost effective and eco-friendly green synthesis. Moreover, activity of TiO 2 NPs as catalysts and their effect on biodiesel selectivity is discussed using catalytic trans -esterification, esterification, and simultaneous trans -esterification and esterification processes. The combinations of TiO 2 NPs with other metallic and non-metallic materials are very selective and efficient for biodiesel production upto 98 %. This study appeals to research communities for adopting green synthesized TiO 2 NPs as nanocatalysts for eliminating economic and environmental issues. [ABSTRACT FROM AUTHOR]

[Display omitted] • Different peroxides-based oxidative pathways were compared towards NOR degradation. • The peroxide HSO 5 − performed best in the degradation of NOR under UV-C and Fe2+. • The peroxides yield ●OH and SO 4 ●− under activation by UV-C and Fe2+ activation. • The ●OH and SO 4 ●− scavengers inhibited degradation of NOR. • Degradation products and ecotoxicities of NOR as well as its DPS were estimated. The removal of norfloxacin (NOR), a widely used pharmaceutical and emerging water pollutant, was studied using UV-C and Fe2+ catalyzed peroxides-based oxidative processes (e.g., UV-C/Fe2+/H 2 O 2 , UV-C/Fe2+/S 2 O 8 2− and UV-C/Fe2+/HSO 5 −) and compared with UV-C and UV-C/Fe2+. The UV-C and UV-C/Fe2+ degraded NOR to 38 and 55 %. However, use of peroxides, i.e., H 2 O 2 , S 2 O 8 2−, HSO 5 − with UV-C and UV-C/Fe2+ promoted NOR %degradation to 75, 83, and 90 % using [peroxides] 0 = 50 mg/L, [Fe2+] 0 = 1 mg/L, and [NOR] 0 = 10 mg/L, respectively. The significant impact of peroxides on NOR degradation was due to their decomposition into ●OH and SO 4 ●− which showed high activity towards NOR degradation. The ●OH and SO 4 ●− formation from peroxides decomposition and their contribution in NOR degradation was verified by different scavenger studies. Among the UV-C/Fe2+/peroxides processes, UV-C/Fe2+/HSO 5 − showed better performance. The changing concentrations of peroxides, Fe2+, and NOR affected degradation of NOR. The use of different pH and inorganic anions also influenced NOR degradation. The degradation pathways of NOR were established and analyzed acute as well as chronic toxicities of NOR and its DPs. [ABSTRACT FROM AUTHOR]

In this study, a novel immobilized TiO2/Ti film with exposed {001} facets was prepared via a facile one-pot hydrothermal route for the degradation of norfloxacin from aqueous media. The effects of various hydrothermal conditions (i.e., solution pH, hydrothermal time (HT) and HF concentration) on the growth of {001} faceted TiO2/Ti film were investigated. The maximum photocatalytic performance of {001} faceted TiO2/Ti film was observed when prepared at pH 2.62, HT of 3 h and at HF concentration of 0.02 M. The as-prepared {001} faceted TiO2/Ti films were fully characterized by field-emission scanning electron microscope (FE-SEM), X-ray diffraction (XRD), high resolution transmission electron microscope (HR-TEM), and X-ray photoelectron spectroscopy (XPS). More importantly, the as-prepared {001} faceted TiO2/Ti film exhibited excellent photocatalytic performance toward degradation of norfloxacin in various water matrices (Milli-Q water, tap water, river water and synthetic wastewater). The individual influence of various anions (SO42-, HCO3-, NO3-, Cl-) and cations (K+, Ca2+, Mg2+, Cu2+, Na+, Fe3+) usually present in the real water samples on the photocatalytic performance of as-prepared TiO2/Ti film with exposed {001} facet was investigated. The mechanistic studies revealed that •OH is mainly involved in the photocatalytic degradation of norfloxacin by {001} faceted TiO2/Ti film. In addition, norfloxacin degradation byproducts were investigated, on the basis of which degradation schemes were proposed. [ABSTRACT FROM AUTHOR]

Water is obligatory for sustaining life on Earth. About 71% of the Earth's surface is covered in water. However, only one percent of the total water is drinkable. The presence of contaminants in wastewater, surface water, groundwater, and drinking water is a serious threat to human and environmental health. Their toxic effects and resistance towards conventional water treatment methods have compelled the scientific community to search for an environmentally friendly method that could efficiently degrade toxic contaminants. In this regard, visible light active photocatalysts have proved to be efficient in eliminating a wide variety of water toxins. A plethora of research activities have been carried out and significant amounts of funds are spent on the monitoring and removal of water contaminants, but relatively little attention has been paid to the degradation of persistent water pollutants. In this regard, nanoparticles of doped ZnO are preferred options owing to their low recombination rate and excellent photocatalytic and antimicrobial activity under irradiation of solar light. The current article presents the roles of these nanomaterials for wastewater treatment from pollutants of emerging concern. [ABSTRACT FROM AUTHOR]

Abstract: The degradation of atrazine, a widely used endocrine disrupting, carcinogenic and persistent herbicide, was investigated by photo-Fenton and photo-Fenton-like advanced oxidation technologies (AOTs): UV/H2O2/Fe2+, UV//Fe2+ and UV//Fe2+. The study was carried out at two pH value conditions, i.e., pH 3.0 and pH 5.8. At pH 3.0, UV//Fe2+ was found to be the most efficient technology whereas UV//Fe2+ was observed to be the most effective at pH 5.8. The degradation of atrazine followed pseudo-first-order reaction with the highest observed rate constant of 2.00×10−2 cm2/mJ in UV//Fe2+ system at the initial concentrations of 4.64μM atrazine, 46.4μM (PMS) and 35.81μM Fe2+. The UV fluence required for the complete removal of 4.64μM atrazine at initially 92.80μM of oxidant and 8.95μM of Fe2+ concentrations at pH 3.0 was found to be 480, 720 and 960mJ/cm2 in UV//Fe2+, UV//Fe2+ and UV/H2O2/Fe2+ systems, respectively. Humic and fulvic acids were found to negatively impact the degradation of atrazine. The removal of TOC was not significant unless a high UV fluence was applied. At an initial concentration of 18.56μM atrazine, 1856.00μM oxidant and 17.91μM Fe2+, a 62.94%, 47.10% and 44.09% decrease in TOC was achieved at a UV fluence of 6000mJ/cm2 in UV/PS/Fe2+, UV/PMS/Fe2+ and UV/H2O2/Fe2+ systems, respectively. Nevertheless, it is suggested in this study that photo-Fenton and photo-Fenton-like technologies are capable of removing atrazine from water efficiently. [Copyright &y& Elsevier]