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Photocatalytic degradation of organic pollution by biochar was a sustainable strategy for waste water remediation, nevertheless, it still suffers drawbacks like low efficiency due to the poor photocatalytic properties of pristine biochar. Herein, amino groups were grafted on the edge sites/defects of biochar by Friedel-Crafts acylation to enhance the degradation of high concentration dye solutions. The results suggested that the amino groups played an important role in imparting photocatalytic properties to biochar. Owing to the strong Lewis basicity and electron-donating ability of amino groups, their interaction with oxygen-containing functional groups/aromatic structures in biochar was improved, which enhanced the electron exchange ability of biochar under visible light irradiation, resulting in excellent degradation performances of high concentration RhB (∼10 times faster than ungrafted biochar). In this work, amino-grafted garlic peel biochar delivered a new idea for the future direction of biochar-based photocatalysis in wastewater remediation. [Display omitted] • Preparation of amino-grafted biochar by Friedel-Crafts acylation. • Amino groups were grafted on the edge sites/defects of biochar. • Amino groups form electron exchange system with different structures of biochar. • Biochar can effectively degrade high concentration RhB as a photocatalyst. [ABSTRACT FROM AUTHOR]

Wastewater containing antibiotics, organic dyes, and waterborne bacteria is a severe threat to human health and the environment. Amoxicillin has a slow metabolism rate in humans. Methylene blue is mutagenic and carcinogenic. In addition, Salmonella causes serious diarrhea. In this study, an effective 2D/2D photocatalyst with excellent elimination of these pollutants was fabricated by combining graphene oxide (GO), Bi 2 WO 6 , BiPO 4 and Ag species. GO was applied at varying loading contents (0.8, 1.6, 2.4, 3.2 wt%) to improve the properties of the photocatalyst toward the removal of representative pollutants. The chemical structures, morphology, light absorption and charge mobility were investigated by different GO loading samples. The results indicated that when the wt% of GO was 2.4%, the photocatalyst showed excellent photocatalytic properties and removal rates for typical pollutants. Amoxicillin and methylene blue were mineralized into CO 2 , H 2 O, and small molecules, while Salmonella was disinfected with excellent photocatalytic efficiency. Furthermore, the possible photodecomposition pathways of amoxicillin and methylene blue were proposed by DFT calculations and intermediates identified by LCMS. The mechanism of the photocatalytic process was investigated by radical trapping experiments, ESR spectroscopy, and Motty-Schottky plots. The free radicals could be produced constantly during the photocatalytic process, leading to mineralization of amoxicillin and methylene blue, and disinfection of Salmonella. In this work, a new perspective on GO modified Bi 2 WO 6 with different loading contents and the degradation pathways of antibiotics and dyes was proposed. [Display omitted] • Exceptional degradability by optimized GO doping photocatalyst was explored. • GO doping improved the activity by modifying light absorption and charge transfer. • The developed GO composite enabled the effective removal towards three pollutants. • The degradation pathways of AMX and MB were elicited by DFT calculations. • 100% mineralization rate is due to vulnerable atoms attacked by continuously generated ROS. [ABSTRACT FROM AUTHOR]

The incessant accumulation of pharmaceutically active compounds (PhACs) in various environmental compartments represents a global menace. Herein, an equimolar high entropy alloy (HEA), i.e., FeCoNiCuZn, is synthesized via a facile and scalable method, and its effectiveness in eliminating four different PhACs from aqueous matrices is rigorously examined. Attributing to its relatively low bandgap and multielement active sites, the as-synthesized quinary HEA demonstrates more pronounced photocatalytic decomposition efficiency, towards tetracycline (86%), sulfamethoxazole (94%), ibuprofen (80%), and diclofenac (99%), than conventional semiconductor-based photocatalysts, under visible light irradiation. Additionally, radical trapping assays are conducted, and the dissociation intermediates are identified, to probe the plausible photocatalytic degradation pathways. Further, the end-products of FeCoNiCuZn-mediated photocatalysis are apparently non-toxic, and the HEA can be successfully recycled repeatedly, with no obvious leaching of heavy metal ions. Overall, the findings of this study testify the applicability of FeCoNiCuZn as a visible light-active photocatalyst, for treating wastewaters contaminated with PhACs. [Display omitted] • An equimolar FeCoNiCuZn high entropy alloy (HEA) is synthesized by induction melting. • The quinary HEA can effectively degrade pharmaceutical residues under visible light. • The plausible photocatalytic degradation mechanism is investigated and proposed. • The photocatalysis end-products do not present any imminent threat to human health. • The HEA exhibits extraordinary stability for repeated usage. [ABSTRACT FROM AUTHOR]

Abstract LaFeO 3 (LFO)-doped acid-modified natural zeolites were prepared by an impregnation-calcination method for the first time. Their effectiveness as photo-Fenton catalysts was evaluated using decolorization of Rhodamine B (RhB) as an organic model. The sample 1HNZ-30LFO was synthesized by using the support of 1HNZ, which was produced via the acid (1 N HCl) treatment of natural zeolite (NZ) at 80 °C for 3 h. It was consisting of approximately 30 wt% LFO and exhibited a higher removal rate of RhB, especially photocatalytic performance, than the pure LFO and parent 1HNZ. This was attributed to the synergistic effect of good adsorption ability of modified zeolite host and a large number of active sites provided by LFO guest for photo-Fenton reaction. Various operational parameters including catalyst dosage, H 2 O 2 concentration, solution pH and dye concentration were examined in the photo-Fenton catalytic degradation of RhB. 98.3% of RhB was degraded under the conditions of 0.8 g L−1 1HNZ-30LFO, 10 mg L−1 RhB, 10 mM H 2 O 2 and initial pH of 6. The catalytic activity of 1HNZ-30LFO was largely retained after 4 cycles of use and recycle; suggesting it could be a promising heterogeneous photocatalyst for dye degradation in wastewater via the photo-Fenton process. Highlights • LaFeO 3 -doped acid-modified natural zeolite was studied for photo-Fenton. • It had improved organic adsorption, facilitating photo-Fenton degradation. • It was much more effective in degrading organic compared to bulk LaFeO 3. • Its use was optimized at solution pH, H 2 O 2 /dye concentration and catalyst dosage. • The good stability and reusability suggested its potential for practical use. [ABSTRACT FROM AUTHOR]

Wastewater containing pharmaceutical contaminants has become a critical environmental concern due to rising population and drug consumption caused by increased life expectancy. Diclofenac (DCF) is one of the most applicable drugs for veterinary and human health purposes, polluting surface waters in different ways. This work aims to synthesize a novel pectin-graphene oxide (GO)-magnesium ferrite (MgFe 2 O 4)-zinc oxide (ZnO) nanocomposite (PGMZ) for photocatalytic degradation of DCF in an aquatic environment under visible light irradiation. The single and synthesized nanocomposites were characterized by several analyses, confirming the successful synthesis of the nanocomposite. Effects of four operation conditions, including nanocomposite dosage (1–1.25 g/L), nanocomposite type, initial contaminant concentration (35–55 mg/L), and solution pH (3–11), were investigated on the degradation performance. From the kinetic study, the effect of mixing two composites, i.e., synergy percentage, was 38.7% when ZnO–MgFe 2 O 4 particles were added to the GO-pectin structure. By examining the effect of different free radical enhancers and scavenging compounds on the DCF photodegradation, the most influential scavenging components were in the following order; NaCl > Na 2 CO 3 > Na 2 SO 4 , while K 2 S 2 O 8 was a better enhancer than H 2 O 2 at their optimal concentration. Finally, the PGMZ photocatalyst was reused six times with a reduction of about 20% in its removal efficiency, indicating excellent reusability and stability. [Display omitted] • Pectin-graphene oxide-magnesium ferrite-zinc oxide nanocomposite was prepared for diclofenac degradation. • Based on the kinetic study, synergy percentage was 38.7% by adding ZnO–MgFe 2 O 4 to the pectin-GO. • DCF degradation process is primarily associated with the generation of.•OH radicals. • Pseudo-first-order model fitted the kinetic data well with a high correlation coefficient (>0.99). • Grafting pectin enhanced the catalyst stability with only 21% reduction in degradation rate after six time reusing. [ABSTRACT FROM AUTHOR]

Intimate coupling of photocatalysis and biodegradation (ICPB) is considered a promising approach for the degradation of recalcitrant organic compounds. In this work, using Trichoderma with benzene degradation ability coupled with activated sludge as a biological source and sugarcane bagasse cellulose composite as a carrier, the ICPB system showed excellent degradation and mineralization of trichlorobenzene under visible light induction. The biofilm inside the ICPB carrier can degrade and mineralize the photocatalytic products. ICPB increased the degradation efficiency of 1,2,3-TCB and 1,3,5-TCB by 12.43% and 4.67%, respectively, compared to photocatalysis alone. The biofilms inside the ICPB carriers can mineralize photocatalytic products, which increases the mineralization efficiency by 18.74%. According to the analysis of intermediates, the degradation of 1,2,3-TCB in this coupled system involved stepwise dechlorination and ring opening. The biofilm in ICPB carrier evolved to be enriched in Cutaneotrichosporon , Trichoderma , Apiotrichum , Zoogloea , Dechloromonas , Flavihumibacter and Cupriavidus , which are known for biodegradable aromatic hydrocarbon and halogenate. Novel microbial seeds supplemented with Trichoderma -based ICPB seem to provide a new potential strategy for effective degradation and mineralization of TCB. The transfer mechanism of trichlorobenzenes is studied by photocatalytic degradation and biodegradation behavior in Trichoderma-based ICPB. [Display omitted] • Intimately coupled photocatalysis and biodegradation (ICPB) was studied. • Construction of ICPB based on Trichoderma and activated sludge as a biological source. • High trichlorobenzenes degradation and mineralization by ICPB were achieved. • ICPB facilitates the reduction of the toxicity of trichlorobenzenes in the environment. • Evolution of microbial community structure under reactive conditions. [ABSTRACT FROM AUTHOR]

Waste zinc carbon (Zn–C) batteries are generated worldwide in a large amount. They are non-rechargeable and costly to recycle. Therefore, they end up in the landfills where they create hazards for humans and for environment as well. Zn–C batteries are rich in concentration of different heavy metals so they can be subjected for the recovery of metals for the development of valuable new materials. In this study authors have proposed an easy hydrometallurgical method for the recovery of zinc from waste Zn–C batteries to synthesize nano zinc oxide (nZnO) photocatalyst. The prepared nZnO particles were irregular in shape, highly crystalline in nature with crystallite size 23.94 nm. The band gap of the photocatalyst was 3.1 eV. The photocatalytic activity of the synthesised nZnO was tested for the degradation of three organic pollutants namely; phenol, p-nitrophenol (PNP) and crystal violet dye (CV) in an aqueous solution under visible light irradiation. nZnO showed a good catalytic efficiency for the degradation of all the three pollutants, however, the crystal violet (CV) removal was best in comparison with the other pollutants, it was minimally effected by the increase in CV concentration. The maximum degradation of phenol, PNP and CV was found to be 95.03 ± 0.2%, 88.63 ± 0.1% and 97.87 ± 0.4%, respectively. The degradation data was fitted best with pseudo-first-order kinetic model. The photocatalyst was recyclable and its regeneration ability was higher for initial three cycles. The intermediate compounds formed in the process of degradation were determined by liquid chromatography and mass spectroscopy (LC-MS) analysis. [Display omitted] • NZnO were prepared from waste zinc carbon batteries. • NZnO was crystalline with crystallite size 23.94 nm and band gap 3.1 eV. • Degradation efficiency was 95% (phenol), 88.63% (PNP) and 97% (CV). • The degradation reaction was followed by pseudo-first-order kinetics. • The prepared nZnO showed good recyclability for three cycles. [ABSTRACT FROM AUTHOR]

ZnO nanorod along with a Zn 2 TiO 4 /GO heterostructure with enhanced charge transfer capability was synthesized by a facile sol-gel method. FT-IR, XRD, XPS, TEM, SEM, EDX, UV–Vis DRS, photocurrent response and PL analyses were applied to characterize the as-prepared photocatalysts. To investigate the photocatalytic activity of the composite, Cefixime (CEF) removal under visible light was evaluated. The ZnO nanorod/Zn 2 TiO 4 /GO, including 65 wt% ZnO and 3 wt% graphene oxide, showed the highest CEF degradation and was selected as the optimal ternary composite. Reduction of electron-hole pair recombination rate, successful interfacial charge transfers, and more visible light reception in the Z-scheme system were the important reasons for improving the photocatalytic properties of ZnO nanorod/Zn 2 TiO 4 /GO. Effective operating parameters in the CEF photocatalytic removal process were optimized employing the response surface method and were as follows: photocatalyst dosage = 0.88 g/L, pH = 5, radiation time = 115 min, and CEF concentration = 10 ppm. The photocatalytic degradation% of CEF and total organic carbon (TOC) removal% under the optimal conditions were 71.4 and 57.5%, respectively, for the three-component composite indicating the production of intermediate species during the process. This photocatalytic reaction confirmed the first-order kinetic and using the ZnO nanorod/Zn 2 TiO 4 /GO composite was able to improve the reaction rate by about 2.7 and 6.2 times more than ZnO nanorod/Zn 2 TiO 4 and ZnO, respectively. The effects of radiation intensity and temperature were investigated and 175 W/m2 and 35 °C were obtained as optimum values. Eventually, according to the trapping test, h+, superoxide radical, and hydroxyl radical are the most effective active species in this photocatalytic reaction, respectively. [Display omitted] • The Z-scheme ZnO nanorod/Zn 2 TiO 4 /GO was synthesized via simple sol-gel method. • Enhanced Cefixime visible-light degradation using ZnO nanorod/Zn 2 TiO 4 /GO. • Graphene Oxide had a notable effect on the catalytic behavior of ZnO/Zn 2 TiO 4 in visible light. • The effect of operational parameters in Cefixime photocatalytic degradation were performed. • h+, O 2 − ͦ were the most effective active species in Cefixime photodegradation. [ABSTRACT FROM AUTHOR]

The photocatalytic removal of 2-chlorophenol (2-CP) from water environment was investigated by TiO 2 –RGO–CoO. Cobalt oxide-loaded TiO 2 (TiO 2 –CoO) supported with reduced graphene oxide (RGO) was synthesized using a sol–gel method and then annealed at 500 °C for 5 min. The material characteristics were analyzed by UV–Vis analysis, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) spectroscopy. Incorporation of cobalt oxide and RGO into the TiO 2 system (TiO 2 –RGO–CoO) lowered the band gap energy to 2.83 eV, which greatly enhanced the visible light absorption. The TiO 2 –RGO–CoO photocatalyst showed complete removal of 20 mg/L 2-CP within 8 h with the addition of 0.01% H 2 O 2 under 100 W visible light irradiation. The photo-degradation efficiency of 2-CP (10 mg/L) was 35.2, 48.9, 58.9 and 98.2% for TiO 2 , TiO 2 –RGO, TiO 2 –CoO and TiO 2 –RGO–CoO, respectively, in the presence of visible light irradiation at solution pH of 6.0. The TiO 2 –RGO–CoO photocatalyst retained its high removal efficiency even after five photocatalytic cycles. [ABSTRACT FROM AUTHOR]

In the present study, an attempt has been made to design a solar light driven N-rGO-ZnO- CoPc(COOH) 8 nanocomposite for the degradation of cyanide. The morphological and structural characterization of the synthesized nanocomposite was performed by XRD, FT-IR, XPS, UV–vis DRS, FESEM, TEM, EDS, PL spectra and BET surface area. The results revealed that almost 91% degradation and 86% toxicity removal occurred at 25 mgL−1 of initial cyanide concentration by the N-rGO-ZnO-CoPc(COOH) 8 nanocomposite under illumination of solar light within 120 min. Analysis of free radicals reveals that the generation of OH. radicals was the predominant species in the photocatalytic degradation process. The cyanide degradation follows pseudo-first order kinetics. The estimated apparent rate constant (K app) of the above nanocomposite was 3 times higher than that of the ZnO photocatalyst alone together with a very good recycle activities. This might be due to the application of metallpthalocyanine photosensitizer CoPc(COOH) 8 which enhances the rate of visible light absorption efficiency and activates the higher band gap ZnO photocatalyst under visible light. In addition, the presence of residual oxygen in N-rGO also promotes nucleation and anchor sites for interfacial contact between ZnO and N-rGO for effective charge transfer. Further, the N-rGO-ZnO-CoPc(COOH) 8 photocatalytic system showed significant antibacterial activities against mixed culture systems. Therefore, the N-rGO-ZnO-CoPc(COOH) 8 nanocomposite may be an alternative solar light driven photocatalyst system for the removal of cyanide from the wastewater along with its strong disinfectant activities. [Display omitted] • A novel N-rGO-ZnO-CoPc(COOH) 8 p-n junction nanocomposite was synthesized. • 3D rectangular nanoplaque CoPc(COOH) 8 photosensitizer enhances visible light absorption. • Cyanide degradation mechanism, kinetics and toxicity removal have been evaluated. • The N-rGO-ZnO-CoPc(COOH) 8 nanocomposite shown a strong antibacterial properties. [ABSTRACT FROM AUTHOR]

In the present study, photodegradation of 4-chlorophenol (4-CP) using a step-scheme BiVO 4 /WO 3 heterostructure under visible LED light irradiation (Vis LED) from aqueous solutions was investigated. The photocatalyst was synthesized through the hydrothermal process and characterized physically and chemically via X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), energy-dispersive X-ray (EDX), and Brunnauer–Emmett–Teller (BET) techniques. The effects of the operational parameters i.e., solution pH, contact time, nanocomposite dosage, and initial 4-CP concentration were evaluated. Results indicated that BiVO 4 /WO 3 /Vis LED process has higher efficiency in 4-CP degradation than BiVO 4 /Vis LED, WO 3 /Vis LED, and BiVO 4 /WO 3 systems. At BiVO 4 /WO 3 concentration of 0.125 g/L, initial pH of 7, and initial 4-CP concentration of 25 mg/L, complete degradation of 4-CP (>97%) was achieved in reaction time of 60 min. The phenol, chlorobenzene, catechol, 4-chlorocatechol, 5-chloro-1,2,4-benzenetriol, hydroquinone, hydroxyhydroquinone, p -benzoquinone, o -benzoquinone, formic acid, acetic acid, and oxalic acid were identified as the major intermediates of 4-CP degradation. In optimal condition, 67.5% and 88.5% of TOC and COD removal rates were obtained in 120 min contact time, respectively. The degradation of 4-CP was pseudo-first-order kinetics. Through the use of tert-Butyl alcohol (TBA) and ethylenediamine tetraacetic acid (EDTA) as radical scavengers, hydroxyl radicals and holes were identified as the main active species in photocatalytic degradation. Also, a tentative pathway for 4-CP degradation using the Vis LED/BiVO 4 /WO 3 process was proposed. • Step-scheme BiVO 4 /WO 3 heterojunction was synthesized through the hydrothermal process. • LED lamps emitting visible light were used as a source of excitation light. • OH and h+ were the main reactive species in 4-CP photodegradation. • The nanocomposite exhibited high reusability and stability at neutral pH. • The intermediate products of 4-CP and degradation pathways were determined via LC-MS. [ABSTRACT FROM AUTHOR]

Environmental concerns have been raised regarding the intense contamination of water resources. Currently, numerous contaminants that reach water bodies are not efficiently removed by conventional water treatment methods. Therefore, there arises the need for development and optimization of efficient treatment methods for the removal of such recalcitrant contaminants. Given the circumstances, the present study aims to use of advanced oxidative processes for dye degradation. For this purpose, copper and zinc doped cobalt ferrites were synthesized by coprecipitation, targeting the degradation of methylene blue dye. The photocatalysts were characterized by XRD, WD-XRF, FE-SEM, N 2 physisorption isotherms, UV–Vis diffuse reflectance spectroscopy, molecular fluorescence spectroscopy and zeta potential. According to the investigation of the degradation mechanism, the holes and hydroxyl radicals were mainly responsible for the dye's degradation. The obtained photocatalysts displayed promising results with up to 99% of dye degradation, employing conventional visible LED lamps, making the practical use of the catalyst highly viable, as well as the economic matters. Additionally, the synthesized materials' magnetic properties allowed total and efficient separation of the catalyst for its reutilization up to 4 cycles, with no decrease in photocatalytic activity and with low leaching of iron ions to solution. Image 1 • Copper and zinc doped cobalt ferrites were synthesized by coprecipitation. • Ferrites used for photodegradation employing conventional LED lamps. • Up to 99% of dye degradation, with low leaching of iron ions. • Magnetic properties allowed total and efficient separation of the catalyst. • The holes and hydroxyl radicals are mainly responsible for the dye's degradation. [ABSTRACT FROM AUTHOR]