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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 1 O 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., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

To clarify the photocatalytic mechanisms of metal-doped Bi 2 WO 6 for fluoroquinolones (FQs) degradation, the effects of the chemical characteristics of four metals, molar ratios of the doped metals, morphology of the catalysts, and electrostatic interactions on the degradation of norfloxacin (NOR) and ciprofloxacin (CIP) were evaluated under visible light irradiation. Experimental results implied that the doping of Mg 2+ , Fe 3+ , Zn 2+ and Cu 2+ dramatically improved the photodegradation of Bi 2 WO 6 for NOR and CIP removal, in which 1% Mg/Bi 2 WO 6 exhibited the highest degradation rate of 89.44% for NOR and 99.11% for CIP. Photodegradation of NOR fitted to the pseudo-first-order model (k 1 value of 0.02576 min -1 ), whereas that of CIP be better described by pseudo-second-order model. Moreover, the two FQs photodegradation pathways and the possible intermediates were summarized. The mechanisms of the metal dopants for the enhancement of photocatalytic activity were attributed to its enhanced specific surface area, electrostatic absorption, as well as the significant photogeneration of ·O 2 - and h + . Also, the photocatalyst exhibited a high stability with 78.5% photocatalytic performance after four cycles of repeated usage., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

In this study, Fe 3 O 4 and microwave (MW) were combined to activate persulfate (PS) for the removal of organic matter, resulting in the enhanced degradation of p-nitrophenol (PNP) in solution. During the preparation of Fe 3 O 4 , the effect of sodium acetate was examined, and the results showed that the concentration of sodium acetate had little effect on the catalytic activity of the Fe 3 O 4 /PS/MW system but did have an effect on the Fe 3 O 4 yield. In addition, with regards to the representative environmental factors, the degradation experiment showed that humic acid and the co-existing anions of chloride, sulfate, nitrate, and phosphate had little effects on p-nitrophenol removal; however, carbonate had a negative effect. In addition, the Fe 3 O 4 /PS/MW system performed well in the initial pH range of 3.0-9.0. According to the quenching experiment and electron paramagnetic resonance (EPR) detection, sulfate radicals and a minority of hydroxyl radicals play dominant roles in the degradation process. In addition, the role of Fe 3 O 4 was confirmed to take part in the degradation process by X-ray photoelectron spectroscopy (XPS) analysis. Because of the good performance observed in the water matrices of tap water and the Songhua River, these results demonstrate the potential application of the Fe 3 O 4 /PS/MW system for wastewater treatment., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

The activation of peroxydisulfate (PDS) by gas/liquid dielectric barrier discharge (DBD) plasma in a flat plate configuration was assessed through phenol removal. The results indicated that PDS addition exhibited a significantly promoting effect on phenol removal and mineralization. In the reaction lacking PDS, phenol in aqueous solution was removed from the initial 10 mg L -1 to 4.75 mg L -1 (by 52.5%), whereas the addition of 1770 mg L -1 PDS increased the overall removal to 78.7%, as indicated by a one-fold increase in the pseudo-first-order kinetic constant. In addition, the corresponding total organic carbon (TOC) removal was increased from 27.5% to 48.4%. Furthermore, an increased input voltage was favourable for increases in phenol removal, the kinetic constant and PDS utilization, which were also influenced by the PDS dose, initial solution pH and water matrix. In addition, through the analysis of radical quenching experiments, the enhancement could be mainly attributed to the production of SO 4 •- and •OH by PDS activation by discharge plasma. The DBD system coupled with PDS exhibited a high removal efficiency for phenol, and thus, the overall findings could provide new insight into wastewater treatment., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Norfloxacin (NOR) is an emerging antibiotics contaminant due to its high resistance to microbial degradation and natural weathering. In this study, Fe-doped ZnS photocatalyst (Zn 0.9 Fe 0.1 S) was deposited on nickel foam (Ni-foam) to improve photocatalytic activity under visible light irradiation. The mass ratio of Zn 0.9 Fe 0.1 S and Ni-foam was optimized to be 0.03 g catalyst versus per g Ni-foam (0.03 Zn 0.9 Fe 0.1 S/Ni-foam), which led to the highest removal rate of 95%. The optimal degradation condition for NOR over 0.03 Zn 0.9 Fe 0.1 S/Ni-foam was pH at 7.0, initial NOR concentration of 5 mg L -1 , and initial photocatalyst concentration of 11.7 g L -1 , with the highest first-order reaction rate constant of 0.025 min -1 and mineralization rate of 63.1%. The NOR removal rate on 0.03 Zn 0.9 Fe 0.1 S/Ni-foam photocatalyst (95%) was approximately four times of that obtained on Zn 0.9 Fe 0.1 S photocatalyst (25%). The increased photocatalytic performance could be attributed to the function of Ni-foam as excellent electron collectors that provided efficient photoinduced charge separation from Zn 0.9 Fe 0.1 S. The reactive species responsible for the degradation of NOR were photo-generated holes, hydroxyl radical, and superoxide radicals. Nearly 90% of the photocatalytic efficiency was retained over seven cycles and the released metal ion concentrations were <0.3% of the total mass of photocatalyst, suggesting high stability of the photocatalyst during the photocatalytic reactions. The aqueous/solid mass transfer and intraparticle mass transfer for Zn 0.9 Fe 0.1 S/Ni-foam were not limiting factors for the degradation of NOR. Therefore the Zn 0.9 Fe 0.1 S/Ni-foam photocatalyst could be applied in the degradation of hazardous pollutants., (Copyright © 2019. Published by Elsevier Ltd.)

An effective peroxymonosulfate activator, ZnCo 2 O 4 , was synthesized through a microwave-assisted method. According to response surface methodology (RSM) using Box-Behnken design (BBD), the effects of four parameters, microwave temperature, microwave time, calcination time and calcination temperature, were investigated, and the results show that both the microwave temperature and calcination temperature have a great influence on the catalytic activity during the preparation process. In addition, a quadratic model is valid for computing and predicting the observed responses. The characteristics of the synthesized ZnCo 2 O 4 catalyst were analyzed with various equipments. The results show that the ZnCo 2 O 4 nanosheets are cubic crystals with a spinel structure and a high surface area of 105.90 m 2 ‧g -1 . Under the conditions of [ZnCo 2 O 4 ] = 0.2 g‧L -1 and [PMS]/[BPA] molar  = 2.0, the bisphenol A degradation efficiency reaches 99.28% within 5 min in the ZnCo 2 O 4 /PMS system. ZnCo 2 O 4 possesses great stability and reusability according to recycling experiments. In addition, the possible active radical species were confirmed through quenching experiments and EPR detection, indicating that surface-bound SO 4 - and OH play vital roles during the degradation process., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Degradation of perfluorooctanoic acid (PFOA) is important because of its global distribution, persistence and toxicity to organisms. In this work, the PbBiFeO 3 photocatalyst was prepared by the hydrothermal method. The effect of doping amount of reduced graphene oxide (rGO) on the decomposition of PFOA was investigated under 254 nm UV light. The results indicated that 100 mg L -1  PbBiFeO 3 with 0.5 wt% rGO exhibited the highest degradation efficiency for 50 mg L -1 PFOA at pH = 2.0 from aqueous solution. The removal rate of PFOA reached 69.6% after 8 h UV irradiation under the optimal conditions (PFOA concentration of 50 mg L -1 , Pb BiFeO 3 /0.5% rGO concentration of 100 mg L -1 , and pH of 2.0). The total organic carbon removal rate and defluorination rate were 28.0% and 37.6%, respectively. During the degradation process, four major intermediates with shorter chain length than PFOA (∼C4C7) were identified. The mechanism responsible for PFOA decomposition was supposed that OH attacked PFOA to form perfluoroalkyl alcohol and then was transferred to perfluoroalkyl fluoride which can easily undergo hydrolysis to form shorter-chain perfluorocarboxylic acids than PFOA. This indicated that the photocatalytic degradation of PFOA was an oxidation process through stepwise losing of CF 2 group., (Copyright © 2018 Elsevier Ltd. All rights reserved.)