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The degradation efficiencies and pathways of metronidazole (MNZ) and amoxicillin (AMX) in binary mixtures by UV/TiO2 photocatalysis were studied. The presence of AMX significantly decreased the degradation of MNZ, whereas the existence of MNZ slightly reduced the degradation of AMX. This is basically due to the difference in attack ability of oxidizing agents present during TiO2 photocatalysis. All oxidizing agents (hydroxyl radicals, superoxide radicals, and holes) could attack AMX molecules, but hydroxyl radicals showed insignificant attack ability in MNZ degradation. In TiO2 photocatalysis of binary mixture, six transformation products were recognized by a high-resolution LC-QTof/MS. Because of competitive effect, only one product was sourced from MNZ degradation and four others were formed due to AMX degradation. The remaining one was a new product of the side reaction. This work indicated that the molecular structure of AMX determined its preferred degradation in a mixture. It not only affected the removal of antibiotics but also figured out the appearance of transformation products. In contrast to single systems, the extent of degradation reduced for each antibiotic in the presence of the second antibiotic was related to the availability of degradation pathways of each antibiotic. Moreover, suitable pH programming was applied to enhance the mineralization of the mixtures. [ABSTRACT FROM AUTHOR]

Notoginsenoside Fc, a protopanaxadiol‐type saponin, shows multi‐pharmacological activities. Chemical stability evaluation plays a crucial role in drug development. In this study, the forced degradation behavior of Notoginsenoside Fc was investigated under hydrolytic and oxidative conditions. A specific ultra high performance liquid chromatography with quadrupole time‐of‐flight mass spectrometry was developed for the separation, identification, and characterization of the degradation products of Notoginsenoside Fc. Fifty potential degradation products were formed via deglycosylation, dehydration, hydration, isomerization, side‐chain cleaving, oxidation, and superoxidation. Notoginsenoside Fc was subjected to different pH solutions, temperatures, and time periods to assess its stability. A sensitive ultra high performance liquid chromatography‐tandem mass spectrometry was developed for the quantification of Notoginsenoside Fc, notoginsenoside ST‐4, notoginsenoside Ft1, and relative quantification of notoginsenoside Ft2, 20(R)‐notoginsenoside Ft2, notoginsenoside SFt3, and notoginsenoside SFt4. The assay was linear over the concentration range (R2 > 0.997) with the lowest limit of quantification of 0.02 μg/mL for Notoginsenoside Fc, Notoginsenoside ST‐4, and Notoginsenoside Ft1. The intra‐day precision, inter‐day precision, and accuracy of the three analytes were within accepted levels. The degradation kinetics of Notoginsenoside Fc in pH 1 and 3 solutions fits to first‐ and second‐order kinetics, respectively. The degradation of Notoginsenoside Fc is pH‐, temperature‐, and time‐dependent. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Yb-doped PbO 2 electrode were prepared by electrodeposition methods. • The addition of Yb can enhance the stability and electrochemical activity of PbO 2 electrode. • Electrocatalytic degradation of acetamiprid was investigated by Yb-doped PbO 2 anode. • The intermediates were identified and oxidation mechanism of acetamiprid was elucidated. • The Yb-doped PbO 2 electrode is promising anode material for pollutants degradation. Abstract The Yb-doped PbO 2 electrodes were fabricated by electrodeposition method. SEM and XRD experiments revealed that the adulteration of Yb can decrease the crystal grain size and make the electrodes more compact. Electrochemical measurements, accelerated service lifetime and bulk electrolysis experiments proved that Yb-doped PbO 2 electrodes had higher oxygen evolution overpotential, stability and acetamiprid removal ratio than pure PbO 2 electrodes. The effect of operating parameters, such as current density, initial acetamiprid concentration, and pH value, on the electrocatalytic degradation of acetamiprid were systematically studied. The electrocatalytic oxidation reaction of acetamiprid on Yb-doped PbO 2 electrodes was highly effective, which obeyed the pseudo-first-order kinetics model. Intermediates analysis and electrocatalytic degradation mechanism of acetamiprid by Yb-doped PbO 2 electrodes were implemented, and the degradation pathways were divided into three different sub-routes due to three function groups on acetamiprid initially attacked by hydroxyl radicals. Finally, all the byproducts were decontaminated into CO 2 and H 2 O. These results proved that Yb-doped PbO 2 electrodes have more promising application potential for the electrocatalytic degradation of refractory organic pollutants. [ABSTRACT FROM AUTHOR]

Highlights • NTP and ZnO-rGO nanosheetes were firstly used to ignite methylparaben degradation. • Degradation rates of methylparaben were greatly enhancement in NTP/ZnO-rGO system. • Intermediate products and the degradation mechanism of methylparaben were proposed. • The ZnO-rGO nanosheetes had perfect stability and activity. Abstract The feasibility of methylparaben (MeP) degradation in aqueous solution by dielectric barrier discharge induced non-thermal plasma combined with zinc oxide-reduced graphene oxide (ZnO-rGO) nanosheets was investigated. The ZnO-rGO nanosheets were synthesized by hydrothermal method and characterized by X-ray diffraction, nitrogen adsorption-desorption isotherm, scanning electron microscope, transmission electron microscope, UV–vis absorption spectroscopy, photocurrent, photoluminescence spectroscopy and X-ray photoelectron spectroscopy. The effects of various factors (discharge power, initial concentration of MeP, initial pH value and air flow rate) on the degradation of MeP were evaluated and the changes of solution pH, conductivity and TOC during the degradation process were discussed. The results showed that when the discharge power was 20 W, the airflow rate was 20 L/h, the ZnO-rGO nanosheets dosage was 0.015 g/L, the initial concentration of MeP was 20 mg/L, and the initial pH value was 7.0, the degradation efficiency of MeP achieved 99% at 15 min. The adding of ZnO-rGO nanosheets to the non-thermal plasma system greatly enhanced the degradation efficiency of MeP. In addition, the role of some reactive species during the degradation process of MeP was also investigated. The degradation process of MeP was well fitted by the pseudo-first-order kinetics. Good stability of the synthetic ZnO-rGO was observed. The degradation intermediates of MeP were determined by gas chromatography-mass spectrometer and the degradation pathways were proposed. Under the attack of reactive species, conjugated structure destruction, hydroxylation, carboxylation and ring-opening reaction occurred during MeP degradation, resulting in the formation of organic acids and alcohols; furthermore, some of the degradation intermediates were mineralized to H 2 O and CO 2. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • ZnO/Fe 2 O 3 /g-C 3 N 4 heterojunction was prepared with a loosened multilayered structure. • The heterojunction exhibited excellent photocatalytic degradation towards sulfonamides. • Sulfonamides spiked in actual surface water could be efficiently removed. • The mechanism of amorphous Fe 2 O 3 -mediated Z-scheme photocatalysis was proposed. • Degradation pathways were elucidated based on byproducts identified by QToF-MS. Abstract ZnO grafted amorphous Fe 2 O 3 matrix (ZnO/Fe 2 O 3) was coupled with g-C 3 N 4 to synthesize heterojunction photocatalysts with a loosened multilayered structure. The ZnO/Fe 2 O 3 /g-C 3 N 4 exhibited enhanced photocatalytic performance in the degradation of sulfamethazine under visible-light irradiation (λ > 420 nm), with an optimum photocatalytic degradation rate approximately 3.0, 2.4 times that of pure g-C 3 N 4 and binary ZnO/g-C 3 N 4. Moreover, the target sulfonamides spiked in actual surface water samples could be efficiently photodegraded by ZnO/Fe 2 O 3 /g-C 3 N 4 after 8 h of irradiation, demonstrating its practical potential. An amorphous Fe 2 O 3 -mediated Z-scheme mechanism was proposed for the charge transfer at the heterojunction surface, which involved a Fe(III)/Fe(II) oxidation-reduction center that favored the retarded charge recombination and improved photocatalytic activity. Such a mechanism was well supported by the direct detection of surface generated O 2 − and OH reactive species. Finally, detailed transformation pathways were proposed based on the photodegradation products identified by QToF-MS analyses. This work provides an illustrative strategy for developing efficient Z-scheme photocatalysts for water purification, by taking advantage of amorphous Fe-based oxides in the semiconductor lattice matching. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Co-incorporated α-FeOOH as a quite efficient catalyst for ozonation. • Enhancement of OH generation and oxidation/minerlization efficiency of atenolol. • 19 organic intermediates and one inorganic product of atenolol were identified. • The proposed degradation pathway of atenolol was systematically elucidated. Abstract Co-incorporated α-FeOOH nanocrystal (Co-FeOOH) was synthesized and applied for the ozonation of atenolol (ATL) in water. The compound was characterized and recognized as a transitional structure from FeOOH to CoFeO 4. The presence of Co-FeOOH was observed to support the formation of •OH by promoting ozone decomposition, and the degradation of ATL and TOC was significantly improved during the catalytic ozonation. Catalytic reactions were rationally designed in different water matrices, efficient and simultaneous removal of ATL and natural organic contaminants was achieved. It was found that the reactions kinetics depend strongly on the solution pH which could alter the surface properties of catalyst and influence the ozone-decomposition. Based on the 19 organic intermediates identified by UPLC/Q-TOF-mass spectrometry, possible reaction pathways were accordingly proposed to elucidate the mechanism of atenolol degradation by ozone molecular and •OH. Three positions of ATL structure were concluded as the most vulnerable sites to be attacked by oxygen species to initiate the degradation path. [ABSTRACT FROM AUTHOR]

Herein, we report the comparison of two different mixing methods for reductive dechlorination of gamma‐hexachlorocyclohexane (γ‐HCH), aldrin, and p, p'‐dichlorodiphenyl‐trichloroethane (p, p'‐DDT), using iron/palladium (Fe/Pd) bimetallic nanoparticles. A noticeable enhancement of the reaction rate was found when the reductive dechlorination reaction was carried out in an ultrasound bath as compared with a platform shaker. These enhancements could be attributed to (a) the continuous cleaning and chemical activation of the surfaces of nanoscale Fe/Pd bimetallic nanoparticles by the combined chemical and physical effects of acoustic cavitation; and (b) the accelerated mass transport rates of target POPs to the surfaces of the Fe/Pd nanoparticles. Finally, the degradation intermediates and final products were determined by gas chromatography/mass spectrometry (GC/MS) analysis and the plausible degradation pathways for γ‐HCH, aldrin, and p, p'‐DDT by Fe/Pd bimetallic nanoparticles were proposed. Practitioner points: Exposure to POPs is a resilient global environmental and health issue.Fe/Pd bimetallic nanoparticles demonstrated > 90 % removal of POPs in the first 30 minutes of the reaction via ultrasonic mixing.GC‐MS analyses provided verification of POPs degradation intermediates and final products. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • CuO@Al 2 O 3 (EPC) was utilized in catalytic PMS process. • Effects of key reaction parameters on SMX removal were studied. • The possible degradation pathway of SMX was proposed. • Toxicity test of degraded solution was conducted. • The catalytic mechanism of CuO@Al 2 O 3 (EPC)/PMS system was proposed. Abstract The CuO@Al 2 O 3 (EPC) (prepared by an electroless plating and calcining method) was used to activate peroxymonosulfate (PMS) for advanced oxidation of sulfamethoxazole (SMX) in deionized water, and effects of three key parameters of its all parameters (i.e., CuO@Al 2 O 3 (EPC) dosage, PMS dosage, and initial solution pH) on the CuO@Al 2 O 3 (EPC)/PMS system were studied. Under the optimal conditions (i.e., [catalyst] 0 = 0.5 g/L, [PMS] 0 = 0.4 mM and initial solution pH of 6.2), the SMX removal efficiency obtained by the CuO@Al 2 O 3 (EPC)/PMS process was 99%, while the SMX removal efficiency were 76% and 72% in CuO@Al 2 O 3 (IC) (prepared by an impregnation-calcination method)/PMS and CuO/PMS system respectively. Adding H 2 PO 4 − into CuO@Al 2 O 3 (EPC)/PMS system decreased the SMX removal efficiency, while the degradation efficiency was improved when Cl− was introduced the oxidation system. Furthermore, five possible degradation pathways of SMX were proposed according to the analysis results of intermediates detected by UPLC-QTOF-MS/MS. The biological toxicities of the degraded SMX solution were evaluated by activated sludge inhibition experiments. What is more, it was found that three radicals (i.e. SO 4 −, OH and O 2 −) made contributions to SMX degradation in the CuO@Al 2 O 3 (EPC)/PMS system according to radicals scavenging experiments. Residual PMS, and generated SO 4 − and OH radicals were quantified in CuO@Al 2 O 3 (EPC)/PMS system, and the electron paramagnetic resonance (EPR) was used to detect the generation of radicals. Finally, the mechanism of the CuO@Al 2 O 3 (EPC)/PMS system was proposed according to analysis data of XPS and radical scavenging experiments. [ABSTRACT FROM AUTHOR]

Abstract CuO nanostructured thin films supported on silicon with 6.5 cm2 area (geometric area greater than the studies reported in the literature) were synthesized by a chemical bath deposition technique. The electrodes were characterized by MEV, XRD, XPS, contact angle, cyclic voltammetry and electrochemical impedance spectroscopy analyses. To evaluate the photoelectrochemical properties of the CuO films, photocurrent–voltage measurements were performed using linear voltammetry. The catalytic activities of CuO nanostructures were evaluated by monitoring photodegradation of Mitoxantrone (MTX) under UV-A light irradiation. The method of photoelectrocatalysis (PEC), applying a voltage of 1.5 V and assisted by adding H 2 O 2 , was undertaken. To the best of our knowledge, no studies on the degradation of anticancer agents using PEC process have been found in the literature. For comparison purposes, experiments were performed under the same conditions by assisted photocatalysis (PC) with H 2 O 2 and direct photolysis. CuO deposits consist of a needle-like morphology. The presence of CuO in the tenorite phase was evidenced by XRD and the XPS spectra showed the presence of copper(II) oxide. The increase in current under illumination shows that CuO exhibits photoactivity. The PEC system showed a 75% level of MTX degradation, while the level achieved using PC was 50%. Under UV-A light alone only 3% removal was obtained after 180 min. Up to 10 by-products were identified by chromatography-mass spectrometry (LC-MS) with m / z values ranging between 521 and 285 and a plausible degradation route has been proposed. It is worth mentioning that 9 by-products identified in this work, were not found in the literature in other studies of degradation or products generated as metabolites. The toxicity tests of MTX before and after PEC treatment with Artemia Salina and Allium cepa showed a decrease in the acute toxicity of the medium as the antineoplastic was degraded. Graphical abstract Unlabelled Image Highlights • Needle-like CuO nanostructures were grown on Si substrates using a CBD method. • High photoelectrocatalytic performance of CuO film is related to its needle-like nanostructure. • Enhanced H 2 O 2 -assisted PEC degradation by CuO film electrodes it was demonstrated. • The MTX drug exhibits high acute toxicity against Artemia salina and Allium cepa. • By-products generated by photoelectrocatalysis are substantially less toxic. [ABSTRACT FROM AUTHOR]

Abstract In this study, the effects of water matrix components such as anions (Cl−, SO 4 2−, NO 3 −, HCO 3 −, and H 2 PO 4 −); cations (Ca2+, Mg2+, and Fe3+); natural organic matter (humic acid); and pharmaceutical excipient (glucose) on the photocatalytic degradation of metronidazole (MNZ) by UV/TiO 2 were investigated. Degradation of MNZ noticeably decreased in the presence of H 2 PO 4 −, Fe3+, and humic acid (HA). However, the addition of glucose tripled the rate of MNZ degradation. The transformation products formed during photocatalysis were detected and identified using Waters UPLC-QTof/MS (ultra-performance liquid chromatography–quadrupole time-of-flight mass spectrometry) and UPLC-MS/MS (ultra-performance liquid chromatography–tandem mass spectrometry) instruments. The enhanced degradation of MNZ in the presence of glucose was due to the side reactions of MNZ and its intermediates with other organics released when glucose was degraded. HA could activate charge transfer steps, resulting in different photodegradation products. Iron(III) ions competed with MNZ under light adsorption and reacted with organic intermediates, which hindered MNZ degradation. The presence of H 2 PO 4 − ions seemed to have no effect on the degradation pathways of MNZ but only slowed down the removal of MNZ and its intermediates by interacting with TiO 2. These results indicate that the presence of water matrix components significantly changed the degradation pathways and hence affected the degradation efficiency. Graphical abstract The effect of the presence of water matrix components on photodegradation removal of antibiotic metronidazole (MNZ) using UV/TiO 2 catalysts was comprehensively examined. These components not only impact on degradation efficiency but also cause changes in degradation pathways by forming new transformation products. These products were detected and identified by both UPLC®-QTof/MS and UPLC®-MS/MS. Among a variety of water matrix components assessed, it was concluded that the existence of the popular natural organic matter humic acid (HA) and common pharmaceutical excipient glucose will significantly change the degradation pathways. Unlabelled Image Highlights • TiO 2 photocatalysis of MNZ in the presence of anions, cations, humic acid, and glucose is studied. • Transformation products formed in photocatalysis are identified by LC-QTof/MS and LC-MS/MS. • The presence of glucose causes side-reactions that promotes degradation efficiency. • Humic acid will activate electron transfer that results in the formation of new intermediates. • The presence of Fe3+ ions hinders UV photocatalysis of MNZ by a complexation reaction. [ABSTRACT FROM AUTHOR]

Monitoring the light-induced decomposition course of azo dyes is essential to understand their degradation pathways and mechanisms. In this study, two model dyes are synthesized and used for stimulating the photodegradation processes of azo and hydrazone dyes, respectively. Their intermediates formed during initial and final fading processes are characterized by high-performance liquid chromatography-electrospray ionization-mass spectrometry, gas chromatography-mass spectrometry and ion chromatography. Results reveal that no dramatic differences are observed between the two dyes, although hydrazone dye would undergo a more complicated degradation process. Hydroxyl radicals are the dominant reactive species involved in the photodegradation of both model dyes under ultraviolet irradiation. In the initial steps, the intermediates are almost hydroxylated derivatives, while low-molecular-weight dicarboxylic acids and their hydroxylated and esterified derivatives, as well as non-volatile inorganic ions, are detected and evidenced in the final steps. Furthermore, photodegradation pathways and mechanisms for the two model dyes are proposed accordingly. [ABSTRACT FROM AUTHOR]

The unique properties of ionic liquids make them suitable candidates to prepare nanoscale materials. A simple method that uses exclusively a corresponding bulk material and an ionic liquid—in this case, [P6,6,6,14]Cl—was used to prepare AgCl nanoparticles and AgCl@Fe3O4 or TiO2@Fe3O4 magnetic nanocomposites. The prepared nanomaterials were characterized by X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, ultraviolet–visible spectroscopy, and X-ray photoelectron spectroscopy. The photodegradation of atenolol as a model pharmaceutical pollutant in wastewater was investigated under ultraviolet–visible light irradiation using the different synthesized nanocatalysts. In the presence of 0.75 g·L−1 AgCl nanoparticles, a practically complete degradation of 10 ppm of atenolol was obtained after 30 min, following pseudo-first-order reaction kinetics. The effect of different variables (concentrations, pH, oxidant agents, etc.) was analyzed. The recyclability of the nanocatalyst was tested and found to be successful. A degradation mechanism was also proposed. In order to improve the recovery stage of the nanocatalyst, the use of magnetic nanocomposites is proposed. Under the same experimental conditions, a slightly lower and slower degradation was achieved with an easier separation. The main conclusions of the paper are the suitability of the use of ionic liquids to prepare different nanocatalysts and the effectiveness of these at degrading an emerging pollutant in wastewater treatment.

[Display omitted] • Facile construction of magnetic Fe 3 O 4 –COOH integrated with MOGs is achieved. • The adsorption-photocatalysis synergistic mechanisms of Fe 3 O 4 /MOGs are proposed. • Toxicity assessment coupled with the CTC degradation pathways are evaluated. • Fe 3 O 4 /MOGs are immobilized in SA to attain great sustainability and recyclability. • Fe 3 O 4 /MOGs/SA beads realize long-term continuous operations for CTC elimination. The development of highly efficient and easily recyclable materials remains at the forefront of chlortetracycline hydrochloride (CTC) remediation. Herein, two magnetic metal-organic gels (Fe 3 O 4 /Fe-MOG and Fe 3 O 4 /Al-MOG) are constituted by an ultrafast room-temperature synthesis of MOGs on the surface of carboxylated Fe 3 O 4 , affording exceptional adsorption-photocatalysis abilities towards CTC under visible light irradiation, along with favorable magnetic separation capabilities. Meanwhile, the proposed synergistic mechanisms of adsorption-photocatalysis, the probable degradation pathways of CTC, and the underlying toxicity evaluation of intermediates are expounded. More importantly, we ingeniously develop Fe 3 O 4 /MOGs/SA beads with sodium alginate (SA) as the backbone and magnetic MOGs as the reaction center, which minimizes the loss of powdered Fe 3 O 4 /MOGs and ameliorates the recyclability. Attractively, Fe 3 O 4 /MOGs/SA beads achieve long-term continuous operation for CTC degradation in various water samples under visible light irradiation. Overall, this work highlights a new possibility for devising immobilized magnetic MOGs with adsorption-photocatalysis synergies in actual and large-scale wastewater remediation. [ABSTRACT FROM AUTHOR]

In situ growth of dispersed active sites on substrates is a strategy for designing highly efficient catalysts for sulfate radical (SO 4 •−)-based advanced oxidation processes (SR-AOPs). Here, magnetic biochar composite (Fe 3 O 4 /BC) was fabricated as an activator to trigger PDS (peroxydisulfate) for norfloxacin (NOR) removal, achieving reliable NOR removal efficiency (>90%) within 10 min. Based on the synergistic effect between Fe 3 O 4 and BC, the removal rate increases to 0.0265 L mg−1 min−1. Fe 3 O 4 /BC exhibited decent adaptability, stability, and recyclability toward affecting factors variation during PDS activation, attributed to the synergistic effect between Fe 3 O 4 and BC. The electron transfer of magnetic Fe 3 O 4 coupled with the adsorption and conduction function of carbon skeleton, which overcomes typical problems as crystal agglomeration, metal leaching, and catalysts recovery etc. The electron-rich Fe(II) sites promote the radical pathway by generating reactive oxygen species (ROS, •OH, SO 4 •− and O 2 •−), and radicals evolution contributing to the form of 1O 2 in non-radical pathway. Under the effect of multipath in NOR degradation, HPLC-QTOF-MS spectroscopy and DFT calculation revealed the possible degradation pathway of NOR. In addition, according to toxicity prediction, the overall NOR contamination toxicity of NOR was effectively alleviated by Fe 3 O 4 /BC + PDS system. Overall, this study presents a promising composite in PDS activation and views the active species evolution in the NOR removal system, which is crucial for mechanism study in relevant research in the future. [Display omitted] • Fe 3 O 4 in collaboration with biochar promotinged the NOR removal to over 90% within 10 min. • The Fe 3 O 4 /BC + PDS system exhibited higher 80% NOR removal efficiency in lake water matrices. • High mineralization (>50%) with minimal leached Fe (<50 μg/L) was maintained after 6 cycles. • Multiple pathways (radical and non-radical pathways) participated in the NOR degradation in the Fe 3 O 4 /BC + PDS system. • Active species (SO 4.•−, •OH, •O 2 −, and 1O 2) evolution process have been systematic investigated. [ABSTRACT FROM AUTHOR]

The presence of organic micropollutants in water bodies represents a threat to living organisms and ecosystems due to their toxicological effects and recalcitrance in conventional wastewater treatments. In this context, the application of heterogeneous photo-Fenton based on magnetite nanoparticles supported on mesoporous silica (SBA15) is proposed to carry out the non-specific degradation of the model compounds ibuprofen, carbamazepine, hormones, bisphenol A and the dye ProcionRed®. The operating conditions (i.e., pH, catalyst load and hydrogen peroxide concentration) were optimized by Response Surface Methodology (RSM). The paramagnetic properties of the nanocatalysts allowed their repeated use in sequential batch operations with catalyst losses below 1%. The feasibility of the process was demonstrated as removal rates above 90% after twelve accomplished after twelve consecutive cycles. In addition, the contributions of different reactive oxygen species, mainly •OH, were analyzed together with the formation of by-products, achieving total mineralization values of 15% on average. [Display omitted] • LED-driven photo-Fenton demonstrated the successful abatement of micropollutants. • Catalyst reusability in twelve reaction cycles was proved through removal tests. • Magnetic separation of catalyst minimized iron losses below 2%. • Hydroxyl radicals were found as the main contributors to reaction kinetics. • By-products were formed mainly through hydroxylation and partial mineralization. [ABSTRACT FROM AUTHOR]

Chlorpyrifos (CP) is a pesticide widely used in agricultural production. However, excessive use of CP is risky for human health and the ecological environment. Microbial remediation has become a research hotspot of environmental pollution control. In this study, the effective CP-degrading strain H27 (Bacillus cereus) was screened from farmland soil, and the degradation ratio was more than 80%. Then, the degradation mechanism was discussed in terms of enzymes, pathways, products and genes, and the mechanism was improved in terms of cell motility, secretory transport system and biofilm formation. The key CP-degrading enzymes were mainly intracellular enzymes (IE), and the degradation ratio reached 49.6% within 30 min. The optimal pH for IE was 7.0, and the optimal temperature was 25 °C. Using DFT and HPLC‒MS analysis, it was found that degradation mainly involved oxidation, hydrolysis and other reactions, and 3 degradation pathways and 14 products were identified, among which TCP (3,5,6-trichloro-2-pyridinol) was the main primary degradation product in addition to small molecules such as CO 2 and H 2 O. Finally, the whole genome of strain H27 was sequenced, and the related degrading genes and enzymes were investigated to improve the metabolic pathways. Strain H27 had perfect genes related to flagellar assembly and chemotaxis and tended to tolerate CP. Moreover, it can secrete esterase, phosphatase and other substances, which can form biofilms and degrade CP in the environment. In addition, CP enters the cell under the action of permeases or transporters, and it is metabolized by IE. The degradation mechanism of CP by strain H27 is speculated in this study, which provided a theoretical basis for enriching CP-degrading bacteria resources, improving degradation metabolic pathways and mechanisms, and applying strain H27 to environmental pollution remediation. [Display omitted] • Bacillus sp. H27 can efficiently degrade CP. • Intracellular enzymes contributed the most to the degradation of CP. • The enzyme activity to degrade CP was affected by temperature and pH. • Three potential biodegradation pathways of CP were identified. • Whole genome of strain H27 was sequenced to improve the degradation mechanism. [ABSTRACT FROM AUTHOR]

The residues of antibiotics in the environment posed serious threat to public health and aquatic ecosystem. This study synthesized a catalyst FeOOH@WS 2 as activator for persulfate (PS)-based advanced oxidation processes (AOPs) system, with sulfachloropyridazine (SAP) as the target pollutant. In the FeOOH@WS 2 /PS system, influence factors such as catalyst dosage, PS concentration, solution pH, inorganic anions and natural organic matter, which could affect the catalytic efficiency for SAP degradation were conducted. Results demonstrated that increasing FeOOH@WS 2 doses and PS concentrations sped up SAP's rate of degradation. Besides, HO⋅, SO 4 •−, O 2 •− and 1O 2 were existed by using the radicals quenching experiments and electron paramagnetic resonance spectrometry (EPR) analysis. It was found that 1O 2 dominated the rapid SAP degradation. According to the intermediates found by analysis, the SAP degradation mechanism was postulated. Additionally, characterization and recycle results implied that the stability and durability of FeOOH@WS 2 were also outstanding. [Display omitted] • PS could be activated at a rapid rate in the FeOOH@WS 2 /PS system. • WS 2 could facilitate reduce Fe3+ FeOOH back to Fe2+ FeOOH and generate W6+. • The catalytic activity of catalyst descended from 96.76% to 70.22% after four consecutive repeated uses. • FeOOH@WS 2 exhibited prominent sulfachloropyridazine (SAP) degradation performance under acidic condition (3−5). [ABSTRACT FROM AUTHOR]

(a) Schematic illustration of synthesizing KNbO 3 /ZnIn 2 S 4 hollow core–shell spheres; Schematic diagram illustrating possible charge-carrier separation and transfer mechanisms of the pure (b) KNbO 3 and (c) ZnIn 2 S 4 samples. [Display omitted] • A novel Z-scheme KNbO 3 /ZnIn 2 S 4 with hollow core–shell microspheres was successfully synthesized. • OH and O- 2 plays an essential role in the photocatalysis process. • he Z-scheme charge transfer mechanism between KNbO 3 and ZnIn 2 S 4 was proposed.. • In-depth photocatalytic degradation pathways for ciprofloxacin were elucidated. Semiconductor photocatalysis technology for environmental remediation faces primary challenges, such as charge-carrier recombination and interfacial charge transfer inhibition, which affect its degradation efficiency in removing organic contaminants. In this work, we successfully synthesized a unique Z-scheme KNbO 3 /ZnIn 2 S 4 hollow core–shell microsphere via a combined hard template, thermal treatment, and hydrothermal processes as the photocatalyst for ciprofloxacin (CIP), oxytetracycline hydrochloride (OTCH), and rhodamine B (RhB) remediation under sunlight irradiation. Compared to the pure KNbO 3 and ZnIn 2 S 4 , our optimized 15-KNbO 3 /ZnIn 2 S 4 composite exhibited enhanced photodegradation performance with up to 99.8 %, 96.8 % and 97.5 % for CIP, OTCH, and RhB removal within 110 min, respectively. At the KNbO 3 /ZnIn 2 S 4 heterojunction interface, the composite developed its internal electric field and enhanced its photoabsorption under visible light region, thus boosting its charge separation. Subsequently, we evaluate the removal of total organic carbon (TOC) concentration and the influence of different ions on CIP degradation. In addition, we systematically investigated the Z-scheme charge migration process within the heterojunction with a series of experiments. Our results indicated that the hydroxyl and superoxide radicals were the dominant active species during photocatalysis. The composite also could achieve excellent stability and adaptability. We also managed to identify the CIP-degraded intermediates and deduce their possible degradation pathways. Lastly, our toxicity analysis revealed that CIP toxicity could decrease gradually during photocatalysis. In this work, we presented a unique method for preparing inexpensive and highly efficient Z-scheme hollow core–shell structure photocatalysts with excellent antibiotic remediation in water under simulated sunlight illumination. [ABSTRACT FROM AUTHOR]

Applying photocatalytic technology to remove pollutants in wastewater represents an ideal pathway to solve the crisis of environmental contamination. However, It's always a great challenge to design efficient, recyclable and multifunctional photocatalysts. Herein, the x wt% Bi/BiPMo 12 O 40 (x = 0.5, 1.0, 2.0 and 3.0) composites were successfully constructed via a hydrothermal method, and characterized with a variety of technological methods. These composites displayed enhanced and persistent photocatalytic activity for removing various pollutants. Specifically, the 1.0% Bi/BiPMo 12 O 40 exhibited optimal performance with the removal efficiencies of 89.33% (Cr(VI)), 77.5% (TC) and 97.5% (MO) under visible light (λ＞420 nm), respectively. Moreover, the influence factors including the Cr(VI) concentration, catalyst dosage, the pH of solution, water quality and inorganic anions, on Cr(VI) reduction were studied in detail. Meanwhile, the degradation products of TC were identified with HPLC-MS, and a feasible degradation pathway was established. The toxicity of intermediates was assessed through QSAR prediction. The outstanding catalytic activity could be attributed to the strong visible absorption, enhanced BET specific surface area and the promotion in separation of photoinduced carriers. Capturing experiments and ERS tests verified the main active substances for Cr reduction (·O 2 − and e−) and TC degradation (·O 2 −, ·OH and h+). Eventually, the reasonable photocatalytic mechanism was proposed. This work provides a rational strategy for designing and constructing of efficient and durable POMs-based catalysts for environmental modification. Novel Bi/BiPMo 12 O 40 composites were successfully fabricated via a hydrothermal method and demonstrated outstanding and persistent visible-light catalytic performance for Cr(VI) reduction and TC/MO degradation, which resulted from the SPR effect of Bi NPs and the Schottky junction between Bi NPs and BiPMo 12 O 40. [Display omitted] • Bi/BiPMo 12 O 40 composites showed good visible-light catalytic activity. • The effects of operating parameters on Cr(IV) reduction were studied. • The degradation pathways of TC were investigated by HPLC-MS. • The toxicity of TC degradation products was evaluated by QSAR prediction. [ABSTRACT FROM AUTHOR]

For a long time, the well-known Gram-positive bacterium Bacillus thuringiensis (Bt) has been extensively studied and developed as a biological insecticide for Lepidoptera and Coleoptera pests due to its ability to secrete a large number of specific insecticidal proteins. In recent years, studies have found that Bt strains can also potentially biodegrade residual pollutants in the environment. Many researchers have isolated Bt strains from multiple sites polluted by exogenous compounds and characterized and identified their xenobiotic-degrading potential. Furthermore, its pathway for degradation was also investigated at molecular level, and a number of major genes/enzymes responsible for degradation have been explored. At present, a variety of xenobiotics involved in degradation in Bt have been reported, including inorganic pollutants (used in the field of heavy metal biosorption and recovery and precious metal recovery and regeneration), pesticides (chlorpyrifos, cypermethrin, 2,2-dichloropropionic acid, etc.), organic tin, petroleum and polycyclic aromatic hydrocarbons, reactive dyes (congo red, methyl orange, methyl blue, etc.), and ibuprofen, among others. In this paper, the biodegrading ability of Bt is reviewed according to the categories of related pollutants, so as to emphasize that Bt is a powerful agent for removing environmental pollutants. • Bacillus thuringiensis (Bt) is a type of widely used bioinsecticide. • Bt is also a powerful agent for the removal of environmental pollutants. • Bt degrades xenobiotics through a variety of degradation mechanisms. • The degradation pathways of organic pollutants by Bt are outlined. [ABSTRACT FROM AUTHOR]

Beta-cypermethrin is one of the widely used pyrethroid insecticides, and problems associated with the accumulation of its residues have aroused public attention. Thus, there is an urgent need to effectively remove the beta-cypermethrin that is present in the environment. Biodegradation is considered a cost-effective and environmentally friendly method for removing pesticide residues. However, the beta-cypermethrin-degrading microbes that are currently available are not optimal. In this study, Pseudomonas aeruginosa PAO1 was capable of efficiently degrading beta-cypermethrin and its major metabolite 3-phenoxybenzaldehyde in water/soil environments. Strain PAO1 could remove 91.4% of beta-cypermethrin (50 mg/L) in mineral salt medium within 120 h. At the same time, it also possesses a significant ability to metabolize 3-phenoxybenzaldehyde—a toxic intermediate of beta-cypermethrin. The Andrews equation showed that the maximum substrate utilization concentrations of beta-cypermethrin and 3-phenoxybenzaldehyde by PAO1 were 65.3558 and 49.6808 mg/L, respectively. Box–Behnken design-based response surface methodology revealed optimum conditions for the PAO1 strain-based degradation of beta-cypermethrin as temperature 30.6 °C, pH 7.7, and 0.2 g/L inoculum size. The results of soil remediation experiments showed that indigenous micro-organisms helped to promote the biodegradation of beta-cypermethrin in soil, and beta-cypermethrin half-life in non-sterilized soil was 6.84 days. The bacterium transformed beta-cypermethrin to produce five possible metabolites, including 3-phenoxybenzyl alcohol, methyl 2-(4-hydroxyphenoxy)benzoate, diisobutyl phthalate, 3,5-dimethoxyphenol, and 2,2-dimethyl-1-(4-phenoxyphenyl)propanone. Among them, methyl 2-(4-hydroxyphenoxy)benzoate and 3,5-dimethoxyphenol were first identified as the intermediate products during the beta-cypermethrin degradation. In addition, we propose a degradation pathway for beta-cypermethrin that is metabolized by strain PAO1. Beta-cypermethrin could be biotransformed firstly by hydrolysis of its carboxylester linkage, followed by cleavage of the diaryl bond and subsequent metabolism. Based on the above results, P. aeruginosa PAO1 could be a potent candidate for the beta-cypermethrin-contaminated environmental bioremediation. • PA01 effectively degraded beta-cypermethrin and its main metabolite 3-phenoxybenzaldehyde. • PA01 successfully colonized and accelerated beta-cypermethrin degradation in soil. • PA01 degraded beta-cypermethrin primarily through hydrolysis pathway by cleaving the ester bond. • PA01 harbors the metabolic pathway for complete degradation of beta-cypermethrin. [ABSTRACT FROM AUTHOR]

TS-1/C3N4 composites were prepared by calcining the precursors with cooling crystallization method and were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction analysis (XRD), UV-Vis diffuse reflection spectrum (DRS) and nitrogen adsorption–desorption isotherm. The photocatalytic performance of TS-1/C3N4 composites was investigated to degrade Rhodamine B (RhB) under visible light irradiation. The results showed that all composites exhibited better photocatalytic performance than pristine TS-1 and C3N4; TS-1/C3N4-B composite (the measured mass ratio of TS-1 to C3N4 is 1:4) had best performance, with a rate constant of 0.04166 min−1, which is about two and ten times higher than those of C3N4 and TS-1, respectively. We attributed the enhanced photocatalytic performance of TC-B to the optimized heterostructure formed by TS-1 and C3N4 with proper proportion. From the results of photoluminescence spectra (PL) and the enhanced photocurrent, it is concluded that photogenerated electrons and holes were separated more effectively in TS-1/C3N4 composites. The contribution of the three main active species for photocatalytic degradation followed a decreasing order of ·O2−, ·OH and h+. The degradation products of RhB were identified by liquid chromatography tandem mass spectrometry (LC-MS/MS), and the possible photocatalytic degradation pathways were proposed.

Antiviral restriction factors are host cellular proteins that constitute a first line of defense blocking viral replication and propagation. In addition to interfering at critical steps of the viral replication cycle, some restriction factors also act as innate sensors triggering innate responses against infections. Accumulating evidence suggests an additional role for restriction factors in promoting antiviral cellular immunity to combat viruses. Here, we review the recent progress in our understanding on how restriction factors, particularly APOBEC3G, SAMHD1, Tetherin, and TRIM5α have the cell-autonomous potential to induce cellular resistance against HIV-1 while promoting antiviral innate and adaptive immune responses. Also, we provide an overview of how these restriction factors may connect with protein degradation pathways to modulate anti-HIV-1 cellular immune responses, and we summarize the potential of restriction factors-based therapeutics. This review brings a global perspective on the influence of restrictions factors in intrinsic, innate, and also adaptive antiviral immunity opening up novel research avenues for therapeutic strategies in the fields of drug discovery, gene therapy, and vaccines to control viral infections.

Graphical abstract Highlights • SO 4 - · contributes more than ·OH in NSAIDs degradation by UV/PS. • Hydroxylation and decarboxylation are main pathways in NSAIDs degradation. • The degradation efficiency of NSAIDs was much lower in real wastewater than in pure water. • The degradation of NSAIDs was inhibited in the presence of humic acid and HCO 3 −. Abstract This study investigated the degradation of three nonsteroidal anti-inflammatory drugs (NSAIDs) (diclofenac (DCF), ibuprofen (IBP) and naproxen (NPX)) by UV/persulfate (UV/PS) in pure water and the influence of wastewater on UV/PS performance. Three NSAIDs have no obvious removal in the PS system, while they all showed a decrease in the UV system, and DCF showed the most significant decrease among the three NSAIDs in the UV system. The degradation of NSAIDs in UV/PS system followed the pseudo first-order degradation kinetics, and the kinetic constants orders are: k DCF > k NPX > k IBP. SO 4 - · contributes more than ·OH in NSAIDs degradation according to tertiary butanol and methanol inhibition tests. According to the degradation products detected by LC-MS, hydroxylation and decarboxylation are main pathways in NSAIDs degradation, and dechlorination is also a main path in DCF degradation. When UV/PS was used to dispose effluents spiked with NSAIDs solution (DCF, NPX, IBP, 0.1 μM each), 10 times of PS dosage and 6 times treatment time were needed to get the same removal in pure water. The water quality parameters (i.e., natural organic matter (NOM), HCO 3 −, Cl− and NO 3 -) affects the degradation of NSAIDs by UV/PS. The degradation efficiency of NSAIDs was inhibited in the presence of humic acid and HCO 3 −. Meanwhile, Cl− and NO 3 - barely influenced the degradation efficiency. [ABSTRACT FROM AUTHOR]

Abstract Given its excellent cleaning ability, environment amity, low toxicity, etc., 1, 1, 2, 2, 3, 3, 4-heptafluorocyclopentane (F7A) has been recommended as a new generation of cleaning agent with great application potential. In this paper, the atmospheric degradation of F7A initiated by reacting with OH radical is studied both in theory and experiment. The experimental rate constants of F7A with OH are tested to be 6.26 × 10−13exp (−954/T) within the temperature range of 303–310 K and the atmospheric lifetime of F7A at 272 K is extrapolated to be 1.69 years. These values show reasonable consistence with the theoretical ones. After that, two possible degradation pathways leading to three main products are given by Gaussian 09. Take the theoretical pathways and the subsequent products analysis into consideration, a model for F7A degradation in atmosphere is built. The short lifetime of F7A and its degradation products contribute F7A an environmentally friendly agent for practical applications. Highlights • The atmospheric degradation of F7A initiated by OH radicals is studied both in theory and experiment. • The theoretical results obtained by Gaussian 09 and KiSThelP agree well with the experimental ones. • The possible degradation pathways of F7A in the atmosphere are proposed. • The impacts of F7A and its degradation products on the environment are limited. [ABSTRACT FROM AUTHOR]

Mycoremediation of low molecular weight polycyclic aromatic hydrocarbons (PAH) is well studied. This study highlights the degradation of high molecular weight PAH (HMW-PAHs): Benz (a) anthracene (BAA), Dibenz (a, h) anthracene (DBA), and Indeno pyrene (IND) by Aspergillus terricola var americanus. The metabolism of the HMW-PAHs by this fungus was investigated in liquid submerged culture added with 60 mg/L of each compound. Depletion of BAA, DBA, and IND was 94.80, 90.16, and 93.80%, respectively, after 10 days of culture. Fungal broth solvent extracts were analyzed for the presence of metabolites by gas chromatography mass spectrometry and the extracellular enzymes produced were also assayed. The coexistence of two metabolic pathways, cytochrome P450 monooxygenase and ligninolytic pathway were identified. A high laccase activity was observed in BAA cultures on day 4 when compared to other PAH's studied. In conclusion, A. terricola might be a promising fungus for bioremediation of HMW-PAH mixtures co-metabolically. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • One-eight-lives method was used to determine the reaction orders. • Possible degradation pathway of ATZ in CuS/PS system was proposed. • The characterizations of CuS were analyzed by SEM, XRD, EDS and XPS, and the stability of CuS was proved. • The mechanism in CuS/PS system was proposed. Abstract In this study, copper sulfide (CuS) was used as a catalyst to activate persulfate (PS) for atrazine (ATZ) degradation. A new method called one-eight-lives was proposed to investigate the kinetic parameters (i.e., atrazine concentration, CuS dosage, PS dosage). The t 1/8 was calculated to analyze ATZ decay and degradation rate of ATZ, which could be expressed by the kinetic rate equation: −d[ATZ]/dt = (2.985 × 10−4 mmol L−1 min−1) [ATZ]0.023[PS]0.76318[CuS]0.80801. Besides, effects of the initial solution pH and the coexisting inorganic anions (i.e., nitrate ions (NO 3 2−), chloride ions (Cl−), bicarbonate (HCO 3 −) and phosphate (HPO 4 2−)) on ATZ degradation were also evaluated during the experiments. Also, the intermediate products were identified by ultrahigh performance liquid chromatograph-mass spectrometry (UPLC-MS). Based on the detected intermediates, possible reaction pathways were proposed. The stability and reusability of the CuS was investigated after three consecutive experiments. Characteristics of the fresh and used CuS were analyzed via SEM, EDS, XRD and XPS techniques. Furthermore, the different systems were set up to investigate the performance of CuS under the same experimental conditions. In addition, the radical scavengers (e.g., methanol, tert-butyl alcohol and phenol) experiences and PS decomposition study revealed that PS activation process occurred on the surface of CuS, and sulfate and hydroxyl radicals were the dominant active species for the ATZ degradation. The generation of sulfate and hydroxyl radicals was further confirmed by electron spin resonance (ESR). Besides, the generation of HO during the reaction process in CuS/PS system was quantified indirectly by HPLC. Finally, the possible reaction mechanism of CuS/PS system was proposed according to the comprehensive analysis. The findings of this study provided useful information for the application of CuS in recalcitrant organic contaminants degradation. [ABSTRACT FROM AUTHOR]

Graphical abstract Novel Z-scheme AgI/Ag/Bi 3 TaO 7 photocatalysts with excellent visible light responsive performance were prepared for the first time. The as-obtained photocatalysts showed significantly enhanced activity for different organic pollutants degradation (antibiotics and dyes) under visible light irradiation. The optimum apparent rate constant reached up to 212 times as high as that of pure Bi 3 TaO 7 for the degradation of sulfamethoxazole. Abstract In this work, novel Z-scheme AgI/Ag/Bi 3 TaO 7 photocatalysts with excellent visible light responsive performance were prepared by a facile hydrothermal reaction combined with ultrasonic assisted precipitation-photoreduction process. The samples were characterized by X-ray power diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV-absorption spectra, electrochemical impedance spectroscopy (EIS) and photoluminescence (PL). The photocatalytic performance of AgI/Ag/Bi 3 TaO 7 composites was assessed by the decomposition of sulfamethoxazole (SMZ) under visible light irradiation. The experimental results revealed that AgI/Ag/BTO-2 showed the best photocatalytic activity for degradation of SMZ (the apparent rate constant was 212 times as high as that of pure Bi 3 TaO 7). The results also showed that the as-prepared AgI/Ag/Bi 3 TaO 7 sample exhibited high activity for the degradation of other organic pollutants (oxcarbazepine, RhB and X-3B). A probable mechanism on the enhanced photocatalytic performance was put forward based on the results of band structure, radicals trapping tests and ESR. In addition, the implanted metallic Ag acted as charge transfer bridge played an important role in the formation of a stable Z-scheme AgI/Ag/Bi 3 TaO 7 system with powerful redox ability. This study offers a good example for the design and development of new efficient visible light responsive photocatalysts for organic pollutants degradation. [ABSTRACT FROM AUTHOR]

Hexagonal boron nitride (BN) nanomaterials that possess an extensive specific surface area, negatively charged properties, high thermal conductivity, and excellent chemical characteristics, have significant advantages for water purification and energy storage. They are typically considered as potential catalysts due to their wide tunable bandgap. Here, carbon nitride (CN) modified BN (CMBN), which facilitated the formation of new C N B bonds, was successfully synthesized using a facile hydrothermal-calcination synthesis strategy. Such highly active bonds made the photocatalyst responsive to a wider range of wavelengths (e.g., ultraviolet to visible blue light), while significantly enhancing photocatalytic activity toward the degradation of enrofloxacin (ENFX). A 3-CMBN sample exhibited 39.3 times, and 2.4 times, higher photocatalytic properties than that of pristine BN and CN, respectively. The remarkable response of 5, 5-dimethyl-1-pyrrolidone -N- oxyl (DMPOX) was investigated through electron spin resonance spectroscopy (EPR) with 3-CMBN, which indicated higher oxidability than BN and CN under blue LED irradiation. Reactive species scavenging experiments revealed that the photodegradation of ENFX was dominated by electron holes and O 2 − . Moreover, the byproducts of ENFX were detected by HPLC-Q-TOF and GC–MS, probable pathways toward these byproducts were deduced, and repeated tests confirmed good stability. These results provided a new strategy to guide the enhanced design of advanced photocatalysts with active chemical bonding species, which can be applied to environmental remediation. [ABSTRACT FROM AUTHOR]

Abstract Atorvastatin (ATV), a second generation cholesterol-lowering drug, is detected frequently in natural water because of its extensive use and incomplete removal from wastewater. In this study, the photochemical behavior of ATV under simulated solar irradiation was systematically investigated in order to assess the potential of photolysis as its transformation pathway in aquatic environment. The quantum yield of ATV direct photolysis was determined to be 0.0041. Among various water components investigated, including pH, Suwannee River Fulvic Acid (SRFA), Fe3+, HCO 3 −, SO 4 2− and NO 3 −, the major factors contributing to the indirect photolysis of ATV were SRFA and NO 3 −, and the co-existence of SRFA and NO 3 − showed no interaction in synthetic water containing the above water components. The results were further verified in natural water samples. Singlet oxygen (1O 2) played dominant role in the indirect photolysis of ATV, and the contributions of 1O 2 and ·OH to the photolysis of ATV in the solution with optimum combination of water components were calculated to be 67.14% and 0.66%, respectively. Nine phototransformation intermediates were identified by liquid chromatography - time-of-flight - mass spectrometry (LC-TOF-MS), and the degradation pathways were speculated as hydroxyl addition, pyrrole-ring open and debenzamide reactions. In addition, the evolution of products in the degradation process showed that the ring-opened product P416 and hydroxylation product P575 still remained at a certain level after two days of photodegradation, which may accumulate and cause additional ecological risks. This study provides significant information for understanding the risk and fate of ATV in aquatic environment. Graphical abstract Image 1 Highlights • The effect of common components in ambient water on the photolysis of ATV was evaluated. • The concentrations of SRFA and NO 3 -were the major influencing factor, and their interaction was additive. • 1O 2 played an important role in the indirect photodegradation of ATV. • Nine degradation intermediates were identified and degradation pathways were proposed. [ABSTRACT FROM AUTHOR]

Abstract This work prepared palladium-doped titanium dioxide (Pd-doped TiO 2) catalysts by a facile sol-gel method to enhance degradation of single and binary methylene blue and methyl orange by ultraviolet photocatalysis. The physicochemical properties of Pd-doped TiO 2 particles were analyzed by a X-ray powder diffractometer, X-ray photoelectron spectroscope, scanning electron microscope, transmission electron microscope, UV–visible diffuse reflectance spectroscope, sorptiometer, and transient photocurrent spectroscope. More efficient degradation was achieved in acidic and basic/neutral media for methyl orange and methylene blue, respectively. Also, methylene blue was always degraded faster than methyl orange. The highest degradation efficiency of both dyes in single and binary systems was obtained using 0.5 wt.% and 0.75 wt.% Pd TiO 2 , respectively. The degradation pathways of single methylene blue and methyl orange with Pd-doped TiO 2 and commercial P25 TiO 2 were proposed and compared by identifying reaction intermediates produced during photocatalysis. Recycling tests have confirmed excellent stability of Pd TiO 2 materials. Also, the prepared materials were easier to separate from the treated liquid using a simple sedimentation or filtration method than P25 TiO 2. In particular, the use of sol-gel method could readily synthesize a large number of catalysts, which was beneficial for scale up consideration. All these factors highlighted their potential and prospect in practical applications for water reuse. Graphical abstract In this work, methylene blue (MB, a thiazine dye) and methyl orange (MO, an azo dye), which have similar molecular weights but different structures, are selected as model pollutants. The Pd-doped TiO 2 catalysts are prepared using a facile sol-gel method for enhanced photocatalysis because this process achieves not only decolorization but also complete mineralization. The intermediates produced during photocatalysis of single dyes are identified by an ultra-performance liquid chromatography-tandem mass spectrometry (UPLC®-MS/MS, Waters), and consequently the degradation pathways are proposed and discussed. Image 1 Highlights • Pd-doped TiO 2 particles with different Pd amount are synthesized and used as photocatalysts. • Degradation of single and mixed methylene blue (MB) and methyl orange (MO) are compared. • Initial concentration, pH, dose and Pd amount of photocatalyst affect degradation efficiency. • Mineralization of dyes highly depends on the intermediates produced during UV photocatalysis. • Degradation pathways of MB and MO are proposed based on UPLC-MS/MS measurements. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The highly efficient LaFeO 3 perovskite oxides were synthesized. • DFT calculations are conducted for PMS adsorption and electron transfer. • ATR-FTIR was used for in situ characterization of LFO surface during catalytic reaction. • Activation mechanisms of PMS by LFO were proposed. • Diclofenac degradation pathways were presented. Abstract A perovskite oxide, LaFeO 3 (LFO), was synthesized and evaluated as a heterogeneous catalyst to activate peroxymonosulfate (PMS) for the oxidative degradation of diclofenac (DCF), a non-steroidal anti-inflammatory drug. It was observed that the catalytic activity of LFO was much higher than that of Fe 2 O 3. LFO catalyzed PMS to degrade DCF with a turnover frequency (2.02 × 10−3 min−1) which is 17-fold higher than that of Fe 2 O 3. Both sulfate and hydroxyl radicals were identified during LFO-activated PMS process by electron spin resonance (ESR). Radical competitive reactions indicate sulfate radicals played a major role in DCF degradation by LFO/PMS process. The PMS decomposition can be attributed to the formation of an inner-sphere complexation between the Fe (III) sites on LFO surface and PMS. Theoretical calculations illustrated the strong interaction between PMS and Fe (III) and electron transfer from PMS to Fe (III). Hydrogen temperature-programmed reduction (H 2 -TPR) indicates that the LFO perovskite oxide is capable of facilitating an easier reduction of Fe (III) to mediate a redox process. Oxygen temperature-programmed desorption (O 2 -TPD) suggests much more oxygen vacancies exist in LFO than in Fe 2 O 3. Oxygen vacancies are favorable for the formation of chemical bond between Fe (III) and PMS and the activation of PMS. In situ ATR-FTIR analysis of LFO surface during PMS decomposition implies Fe (III)–Fe(II)–Fe (III) redox cycle was believed to account for the generation of sulfate radical. The intermediates generated during DCF degradation were identified and the possible degradation pathways were advanced in LFO/PMS system. [ABSTRACT FROM AUTHOR]

Despite many reports of the use of biodegradation to remove contaminants, the biodegradation of polycyclic aromatic hydrocarbons (PAHs) is challenging because of the hydrophobicities and low aqueous solubilities of most PAHs. In this study, phenanthrene (PHE) was used as a sole carbon and energy source to screen and identify Achromobacter sp. LH-1 for the production of biodemulsifiers that enhance the bioavailability and solubilization of PAHs. LH-1 achieved a 94% degradation rate and a 40% mineralization rate with 100 mg/L PHE. Additionally, LH-1 degraded various PAHs, and the factors that influenced the growth and PAHs degradation activity of LH-1 were not only the toxicities and structures of the substances but also the acclimation of LH-1 to these substances. Three kinetic models were used to describe the fermentation processes of cell growth, product formation and substrate degradation over time. Finally, multiple PHE degradation pathways were proposed to be utilized by strain LH-1. [ABSTRACT FROM AUTHOR]

Abstract This paper evaluates the UV photodegradation of 17β-estradiol (E2) on silica gel and in natural soil with different soil components. Silica gel was chosen as a stable and pure support to simulate the photochemical behavior of E2 on the surface of natural soil. Ultraviolet light, rather than visible light, was confirmed to play a decisive role in the photodegradation of E2 on silica gel. The effect of three soil components, including humic acid (HA), inorganic salts, and relative humidity (RH), on the photochemical behavior of E2 on silica gel or soil under UV irradiation was then evaluated. Two HA concentrations (10 and 20 mg g−1) and three salts (ferric sulfate, copper sulfate and sodium carbonate) were observed to obviously inhibit the degradation of E2 on silica gel. Interestingly, nitrate was found to obviously improve the removal efficiency of E2. Both too-dry and too-wet conditions obviously reduced the removal rate of E2, and the optimum relative humidity (RH) value was found to be approximately about 35% (30 °C). Furthermore, twenty intermediate products and two major pathways were proposed to describe the transformation processes of E2 treated by UV irradiation, among which oligomers were found to be the major intermediate products before complete mineralization. The efficient UV removal of E2 on silica gel and natural soil suggested a feasible strategy to remediate E2 contaminated soil. Graphical abstract Image 1 Highlights • UV irradiation rapidly removed E2 on the silica gel and natural soil. • Effect of soil organic matter, mineral salts and relative humidity were studied. • Oligomers were identified as intermediates during UV treatment of E2. • Hydroxylation, oligomerization, ring opening, bond cleavage were observed. • Wiberg bond order was employed to rationalize the reaction mechanism of E2. Silica gel and soil components were mixed together to simulate natural soil and efficient removal of E2 in natural soil by UV treatment was demonstrated. [ABSTRACT FROM AUTHOR]

In this study, effects of the nonuniform weak magnetic field (WMF) on sulfamethoxazole (SMX) degradation rate by H 2 O 2 and persulfate (PS) coupled with different zero-valent iron (Fe 0 ) samples were investigated. The k obs value (pseudo-first-order rate constant) of SMX degradation by Fe 0 /H 2 O 2 or Fe 0 /PS was accelerated by WMF irradiation. Meanwhile, the release rate of dissolved iron was increased in the presence of WMF which indicated WMF irradiation could promote Fe 0 corrosion in Fe 0 /H 2 O 2 and Fe 0 /PS systems. Effects of WMF on SMX degradation kinetics by Fe 0 /H 2 O 2 or Fe 0 /PS in the initial system pH (pH ini ) range of 3.0–7.0 were studied. Although WMF accelerated SMX removal by Fe 0 /H 2 O 2 at pH ini 3.0 and 4.0, WMF did not exhibit advantages at higher pH ini . In Fe 0 /PS systems, WMF could promote SMX removal during the investigated pH range of 3.0–7.0, and k obs of SMX removal depended on the form of aquatic SMX which suggested that SO 4 − could selectively degrade dissociated or protonated SMX. Although SO 4 2− , Cl − , and NO 3 − showed different effects on SMX degradation by Fe 0 /H 2 O 2 or Fe 0 /PS, WMF could accelerate SMX degradation in the presence of these common anions. Chemical quenching experiments and electron paramagnetic resonance (EPR) studies identified that main reactive oxygen species (ROS) generated in Fe 0 /H 2 O 2 /WMF and Fe 0 /PS/WMF systems were OH and SO 4 − , respectively. Meanwhile, the detection of ROS proved that WMF did not change the type of ROS in Fe 0 /H 2 O 2 or Fe 0 /PS systems. Finally, degradation pathways of SMX by Fe 0 /H 2 O 2 /WMF and Fe 0 /PS/WMF were proposed based on transformation products. [ABSTRACT FROM AUTHOR]

Mechanochemical degradation (MCD) is employed for the dechlorination of polychlorinated dibenzo- p -dioxins (PCDD) and -furans (PCDF) in filter ashes from municipal solid waste incinerators, respectively with the assist of six additive systems. The evolution of PCDD/F-signatures in all eleven samples are systematically monitored and studied at the level of individual congeners, and special attention is paid to CP-route congeners, 2,3,7,8-substitution, 1,9-substitution, and 4,6-PCDF. The PCDD/F-isomers distribution follows an analogous pattern, indicating the similar acting mechanism for all additives: additives transfer electrons to attack the C Cl bond and then expulse chlorine. MC dechlorination is not favored for the chlorine on β-position (2,3,7,8-position). The oxygen with stronger electronegativity in PCDD/Fs negatively influences C Cl bond to accept donated electrons, hindering the removal of chlorine on 1,9-position for PCDD, and chlroine on 4,6-position for PCDF. Finally, two fair dechlorination pathways for PCDD and PCDF are respectively proposed based on the detailed analysis of CP-route congeners. The evolution of PCDD-signatures is clear, yet obscure for PCDF-signatures, which still requires further investigations. [ABSTRACT FROM AUTHOR]

Abstract Large amounts of ammunition containing 2,4,6-trinitrotoluene (TNT) and other substances were dumped in the Baltic Sea after WWII. Considering progressive corrosion processes, studying the transformation of TNT occurring in the environment constitutes an important aspect of a possible associated risk. This study focused on the transformations of TNT in simulated conditions of the Baltic Sea bottom sediment. Methods of analysis of TNT and selected products of its transformations were developed for that purpose. The developed methods allowed for the determination of selected compounds below 1 ng/g. Systematic monitoring of TNT transformations in the environment of the bottom sediment was performed. This allowed for the determination of the kinetics of TNT degradation and identification of degradation reaction products. Based on the obtained results, the TNT decay half-time in conditions present in the Baltic Sea was estimated to be 16.7 years for the abiotic environment and 5.6 for the biotic environment. Graphical abstract Unlabelled Image Highlights • Munitions dumped in the Baltic Sea after WWII • Development of methods for determination of TNT and its transformations products • Study on the kinetics of TNT transformation in the simulated bottom sediment • Monitoring of TNT transformation products in biotic and abiotic environment [ABSTRACT FROM AUTHOR]

Highlights • A novel Z-Scheme CdS/Bi 3 O 4 Cl heterostructure photocatalysts are fabricated by a facile surfactant-free method. • The possible degradation pathways of CIP and TC are proposed based on HPLC-MS analysis. • The Z-Scheme CdS/Bi 3 O 4 Cl heterostructures exhibit the excellent mineralization ability towards the CIP and TC molecule degradation. Abstract A novel Z-Scheme CdS/Bi 3 O 4 Cl heterostructure photocatalysts are fabricated by a facile surfactant-free method, and the visible-light-driven photocatalytic activity has been investigated for degradation of ciprofloxacin (CIP) and tetracycline (TC). For degradation of CIP, the Z-Scheme CdS/Bi 3 O 4 Cl-50 heterostructure displays the optimal rate constant (k app = 0.0151 min−1), which is about 10.63 and 1.97 times higher than that of pure Bi 3 O 4 Cl (k app = 0.00142 min−1) and CdS (k app = 0.00764 min−1), respectively. Meanwhile, as expected, the rate constant of Z-Scheme CdS/Bi 3 O 4 Cl-50 heterostructure also displays the highest (0.0643 min−1) for degradation of TC, which is 2.14 times and 4.34 times as high as those of the bare CdS (0.0301 min−1) and Bi 3 O 4 Cl (0.0148 min−1), respectively. The enhancement of phototcatalytic activity is ascribed to the significant improved transfer and separation of charge carriers, which are proved by photocurrent and electrochemical impedance spectra (EIS) measurements. The possible degradation pathway for CIP and TC are proposed based on the HPLC-MS analysis. Compared with pure CdS nanospheres and Bi 3 O 4 Cl nanosheets, the Z-Scheme CdS/Bi 3 O 4 Cl heterostructures exhibit the excellent mineralization ability towards the CIP and TC molecules degradation through the analysis of the total organic carbon (TOC) tests. Moreover, the photocatalytic mechanism over Z-Scheme CdS/Bi 3 O 4 Cl heterostructure under visible light irradiation is investigated by active species trapping experiments and ESR technology. The present work provides a new approach to construct Z-Scheme heterojunction photocatalysts and a deeper insight for the mineralization activity, possible degradation pathways and photocatalytic mechanism. Graphical abstract Image, graphical abstract [ABSTRACT FROM AUTHOR]

Atenolol (ATL) has been widely detected in wastewater and aquatic environment. Although satisfactory removal of ATL from wastewater could be achieved, the mineralization ratio is usually low, which may result in the accumulation of its transformation products in the effluent and cause additional ecological risk to the environment. The aim of this study is to explore the effectiveness of heat activated persulfate (PS) in the removal of ATL from wastewater. Influencing factors including temperature, PS dosage, solution pH, existence of NO 3 − , Cl − , HCO 3 − and Suwannee river fulvic acid (SRFA) were examined. Complete removal of ATL was achieved within 40 min at pH 7.0 and 70 °C by using 0.5 mM PS. Inhibitive effects of HCO 3 − and FA had been observed on ATL oxidation, which was increased with the increase of their concentration. Sulfate radical (SO 4 − ) was determined as the main reactive species by quenching experiment. Eight intermediates produced in ATL degradation were identified, and four degradation pathways were proposed based on the analysis of mass spectrum and frontier electron densities. The distribution of major intermediates was influenced by reaction temperature. Hydroxylation intermediates and deamidation intermediate were the most prominent at 50 °C and 60 °C, respectively. All intermediates were completely degraded in 40 min except P134 at 70 °C. Effective removal of TOC (74.12%) was achieved with 0.5 mM PS, pH 7.0 and 70 °C after 240 min. The results proved that heat activation of PS is a promising method to remove organic pollutants in wastewater. [ABSTRACT FROM AUTHOR]

Nimesulide (Nim) degradation in ultrapure water (UW) and municipal sewage (MS) via UV-ABC/H 2 O 2 was investigated. The variables included in the experimental design were time, initial Nim, and initial H 2 O 2 concentrations. Resulting decreases in Nim concentration (monitored by high performance liquid chromatography (HPLC) using a photodiode array detector operating at a maximum UV absorbance of 300 nm), mineralization (from total organic carbon (TOC) measurements), and ecotoxicity (assays employing the bioindicators Daphnia similis , Artemia salina , and Allium cepa ) were also studied. Degradation rates of 90% or higher were found for 15–20 min reaction times, employing combinations of [H 2 O 2 ] = 50–150 mg L −1 and [Nim] = 8.5–15 mg L −1 prepared with MS. Mineralization rates of 70% and higher were attained within 60 min of reaction for [Nim] = 15 mg L −1 prepared in MS with [H 2 O 2 ] = 100 mg L −1 . Nim by-products were detected and possible degradation pathways proposed. Ecotoxicity evaluation using A. salina , D. similis , and A. cepa revealed that the treated samples had significantly lower toxicity. Exposure to treated samples resulted in survival rates of 79% for A. salina and over 90% for D. similis . No root growth inhibition was observed in A. cepa exposed to treated samples, whereas exposure to untreated samples inhibited root growth by 60%. Statistical analysis revealed elimination of cytotoxicity and reduction of genotoxicity against A. cepa . The results showed that the UV-ABC/H 2 O 2 process can be employed as a pre- or post-treatment method to remove Nim from contaminated wastewater. [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]

A novel strategy for fabrication of visible light driven AgBr-α-NiMoO 4 composite photocatalyst has been developed, including microwave hydrothermal and precipitation-deposition method. The fabrication of heterojunction photocatalyst was proved by XRD, FESEM mapping, HRTEM, SAED, EDS, and XPS techniques. The composite photocatalyst degraded naproxen drug around 84% within 20 min under visible light irradiation. The active species trapping experiment confirmed that OH , O 2 − , and h + play a crucial role for naproxen degradation. Due to efficient charge separation, well matched energy band of AgBr and α-NiMoO 4 as well as surface plasmon resonance of silver particles, the composite revealed the high photocatalytic performance with excellent stability up to fifth cycle. In addition, the composite is photochemical stable. Furthermore, the five degradation pathways were proposed on the basis of retention time and theoretical/observed molecular masses of 19 degraded organic fragments that was confirmed by high-performance liquid chromatography-photodiode array (HPLC-PDA) and high resolution-quadruple time of flight electrospray ionization mass spectroscopy (HR-QTOF ESI/MS) techniques. The different reactions (methylation, demethylation, decarboxylation, hydroxylation, oxidation, and coupling) were observed during NPX degradation by photocatalyst. TOC (total organic carbon) analysis revealed that naproxen drug was completely mineralized by composite photocatalyst within 100 min. So, this work represents the fabrication of visible light induced novel composite photocatalyst for rapid degradation of pharmaceutical pollutant with detailed mechanism and pathways. [ABSTRACT FROM AUTHOR]

A dual element C Cl isotopic study was performed for assessing chlorinated methanes (CMs) abiotic transformation reactions mediated by iron minerals and Fe(0) to further distinguish them in natural attenuation monitoring or when applying remediation strategies in polluted sites. Isotope fractionation was investigated during carbon tetrachloride (CT) and chloroform (CF) degradation in anoxic batch experiments with Fe(0), with FeCl 2 (aq), and with Fe-bearing minerals (magnetite, Mag and pyrite, Py) amended with FeCl 2 (aq), at two different pH values (7 and 12) representative of field and remediation conditions. At pH 7, only CT batches with Fe(0) and Py underwent degradation and CF accumulation evidenced hydrogenolysis. With Py, thiolytic reduction was revealed by CS 2 yield and is a likely reason for different Λ value (Δδ 13 C/Δδ 37 Cl) comparing with Fe(0) experiments at pH 7 (2.9 ± 0.5 and 6.1 ± 0.5, respectively). At pH 12, all CT experiments showed degradation to CF, again with significant differences in Λ values between Fe(0) (5.8 ± 0.4) and Fe-bearing minerals (Mag, 2 ± 1, and Py, 3.7 ± 0.9), probably evidencing other parallel pathways (hydrolytic and thiolytic reduction). Variation of pH did not significantly affect the Λ values of CT degradation by Fe(0) nor Py. CF degradation by Fe(0) at pH 12 showed a Λ (8 ± 1) similar to that reported at pH 7 (8 ± 2), suggesting CF hydrogenolysis as the main reaction and that CF alkaline hydrolysis (13.0 ± 0.8) was negligible. Our data establish a base for discerning the predominant or combined pathways of CMs natural attenuation or for assessing the effectiveness of remediation strategies using recycled minerals or Fe(0). [ABSTRACT FROM AUTHOR]

A composite photocatalyst, AgBr-BaMoO 4 was fabricated by two step method; microwave hydrothermal and precipitation-deposition. The as prepared photocatalyst samples were characterized by various techniques. The facet coupling was seen between the (204) plane of BaMoO 4 and (200)/(222) planes of AgBr on the basis of XRD/HRTEM analysis. The pharmaceutical pollutant, sulfamethoxazole was adopted to investigate the photocatalytic performances of samples under UV–vis irradiation. The AgBr-BaMoO 4 composite degraded the aqueous sulfamethoxazole drug in UV–vis light about 64% within 75 min, which was attributed to efficient separation of photogenerated electron–hole pairs across the interface between Ag/AgBr and BaMoO 4 . The multi-electron induced oxygen reduced reaction (ORR) was observed. The radical trapping experiment indicates that OH • has major role for sulfamethoxazole degradation. The four successive photodegradation of sulfamethoxazole in UV–vis light indicates the stability of composite photocatalyst. Furthermore, the three different degradation pathways were designed on the basis of retention time and molecular masses of 18 degraded organic fragments that was confirmed by high-performance liquid chromatography photodiode array (HPLC-PDA) and high resolution-quadruple time of flight electrospray ionization mass spectroscopy (HR-QTOF ESI/MS) techniques. The total organic carbon (TOC) analysis suggested the mineralization of SMZ by composite photocatalyst. This study not only demonstrates the enhancement of photocatalytic performance of wide band gap semiconductor by making composite with narrow band gap semiconductor but also detail degradation pathways and mechanisms of sulfamethoxazole. [ABSTRACT FROM AUTHOR]

Wheat straw-supported Nanoscale Zero-Valent Iron particles (WS-NZVI) were successfully synthesized, which were used for Ciprofloxacin hydrochloride (CIP) removal in simulation wastewater. The structure, chemical composition and micro-morphology of WS-NZVI and Nanoscale Zero-Valent Iron (NZVI) were characterized by scanning electron microscopy analysis (SEM), X-ray diffraction (XRD), as well as the Fourier Transformed IR spectra (FT-IR). XRD results proved the existence of Fe°, and SEM images indicated that the agglomeration of NZVI was effectively inhibited when loaded on wheat straw. Besides, the effects of initial solution pH, CIP concentration, adsorbents dosage and contacting time on the removal efficiency of CIP by WS-NZVI and NZVI were investigated. The experimental results showed that, compared with NZVI and wheat straw, WS-NZVI possessed higher removal efficiency for CIP, and the maximum removal capacity of CIP by WS-NZVI was 363.63 mg g −1 (25 °C). Furthermore, WS-NZVI was suitable for wider pH range (pH = 4–10) in comparison with NZVI. For the WS-NZVI, the kinetic was better fitted with pseudo-second-order equation, rather than pseudo-first-order equation. The Mass spectrometry (MS) analysis deduced that the degradation reaction mainly occurred on quinolone groups piperazinyl ring. Therefore, it is feasible that using wheat straw as a support material to enhance the performance of NZVI, and the synthesized WS-NZVI has a potential in the organic compounds elimination because of its redox reaction activity. [ABSTRACT FROM AUTHOR]

A nonagon ZnO–ZnFe 2 O 4 nanocomposite was synthesized using high-energy ball milling followed by post-annealing with an initial mixture of high purity magnetite (Fe 3 O 4 ) and zincite (ZnO) powders. The effects of the process parameters on the structural, optical, photocatalytic, and photoelectrocatalytic activities were investigated. X-ray diffraction analysis was used to confirm the presence cubic spinel ZnFe 2 O 4 and hexagonal ZnO crystal phases. The lowest optical bandgap observed was 1.83 eV, which decreased due to post-annealing. The photocatalytic activity of the 800 °C post-annealed nanocomposite exhibited the highest degradation percentage of 96% over 180 min under visible light, with a degradation rate constant of 1.5 min −1 . Furthermore, the optimized sample showed no substantial decrease in photocatalytic activity after five cycles of the repeated catalysis experiment. In electrochemical studies, when compared to the other post-annealed samples, the 800 °C post-annealed nanocomposite showed the highest water splitting activity with the lowest charge-transfer resistance of 75 Ω, photocurrent density of 4.3 × 10 −5  Acm −2 , exchange current density of 4.19 log JA −1  cm −2 , and Tafel slopes of 74.1 mVdec −1 . In dual activities, the performance of the 800 °C post-annealed nanocomposite was noticed to be enhanced. This nanocomposite has potential industrial applications as a cost-effective catalyst. [ABSTRACT FROM AUTHOR]