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Highlights: [•] β-FeOOH/Al2O3 showed high efficiency for BrO3 − inhibition and pollutants removal. [•] BrO3 − was reduced to Br− on the surface of β-FeOOH/Al2O3 by surface Fe(II). [•] The surface Fe(II) was from the reaction of Fe(III) with HO2 − in O3 decomposition. [•] The complexation of Fe(III) with COOH could enhance the surface Fe(II) generation. [Copyright &y& Elsevier]

Abstract: Fe-200 was synthesized through the calcination of iron powder at 200°C for 30min in air. On the basis of characterization by X-ray diffraction and X-ray photoelectron spectroscopy, Fe-200 had a core–shell structure, in which the surface layer was mainly composed of Fe2O3 with some FeOOH and FeO, and the core retained metallic iron. The kinetics and mechanism of the interfacial electron transfer on Fe-200 were investigated in detail for the photoassisted degradation of organic pollutants with H2O2. Under deoxygenated conditions in the dark, the generation of hydroxyl radicals in aqueous Fe-200 dispersion verified that galvanic cells existed at the interface of Fe0/iron oxide, indicating the electron transfer from Fe0 to Fe3+. Furthermore, the effects of hydrogen peroxide and different organic pollutants on the interfacial electron transfer were examined by the change rate of the Fe3+ concentration in the solution. The results indicated that hydrogen peroxide provided a driving force in the electron transfer from Fe2+ to Fe3+, while the degradation of organic pollutants increased the electron transfer at the interface of Fe0/iron oxide due to their reaction with imple-para> [Copyright &y& Elsevier]

Abstract: Magnetic cobalt-doped Fe3O4 (FeCo) was prepared using a co-precipitation method and characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV), and in situ attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy. The catalyst showed high, stable catalytic activity for the degradation and mineralization of toxic persistent organic pollutants, as demonstrated with the herbicides 2,4-dichlorophenoxyacetic acid, 2,4-dichlorophenol, and 2,4,6-trichlorophenol and pharmaceutical phenazone in aqueous solution with ozone. FeCo was very effective at the mineralization of refractory oxalic acid produced in the degradation of organic compounds. The ozone was adsorbed on the surface of FeCo competing with water molecules in the aqueous phase, and converted into hydroxyl radical, meanwhile the catalyst surface underwent oxidation and reduction as demonstrated by in situ ATR-FTIR, CV and other experimental data obtained. Furthermore, the characterization studies indicated that the introduction of Co increased the rate of FeCo oxidation and reduction during the decomposition of ozone, enhancing the activity and stability of Fe3O4. [Copyright &y& Elsevier]

Abstract: Magnetic Co- and Co, Mn-doped γ-Fe2O3 (FC and FCM) were prepared by co-precipitation method and characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), in situ attenuated total reflection FTIR (ATR-FTIR) spectroscopy and cyclic voltammetry (CV) analyses. FCM was found to be highly effective for the mineralization of 2,4-dichlorophenoxyacetic acid and its derivatives 2,4-diclorophenol, 2,4,6-trichlorophenol in aqueous solution with ozone. The characterization studies showed that Co and Mn incorporated in γ-Fe2O3 existed as multivalence oxidation states, and there were more Lewis acid sites on the surface of FCM. The interaction of ozone with chemisorbed H2O and surface hydroxyl groups generated from dissociative adsorption of H2O on Lewis acid sites initiated the production of reactive oxygen species. Moreover, a redox process was observed in the catalytic decomposition of O3 at the water–catalyst interface by CV analysis. The results indicated that the introduction of Mn not only increased the surface Lewis acid sites of FCM to cause more surface hydroxyl groups and chemisorbed water, but also enhanced the interfacial electron transfer, resulting in higher activity. [ABSTRACT FROM AUTHOR]

Abstract: The surface acidity and reactive activity of β-FeOOH, mesoporous alumina (MA), β-FeOOH/MA were investigated in catalytic ozonation of pharmaceutically active compounds (PhACs) aqueous solution. β-FeOOH/MA showed high efficiency for the degradation and mineralization of ibuprofen and ciprofloxacin. Its surface Lewis acid sites on β-FeOOH/MA were more greatly enhanced compared with those on MA and β-FeOOH. In situ attenuated total reflection FTIR (ATR-FTIR) spectroscopy was used to investigate the interaction of D2O and O3 with the catalysts in aqueous phase under various conditions. The dissociative chemisorptions of D2O occurred at the surface Lewis acid sites of the catalyst. Furthermore, O3 interacted with the surface hydrogen-bonded –O–D and D2O to initiate reactive oxygen species (ROS). The stronger Lewis acid sites of β-FeOOH/MA caused the more chemisorbed water enhancing the interaction with ozone, resulting in higher catalytic reactivity. The observations verified that the Lewis acid sites were reactive centers for the catalytic ozonation of PhACs in water. [Copyright &y& Elsevier]

An essential strategy to eliminate emerging contamination in water is to initiate more reactive oxygen species (ROS) in the catalytic systems. 0.14 wt.% Au loaded Bi 2 WO 6 (Bi 2 WO 6 /Au-400 °C) was fabricated after 400 °C annealing with the assistance of glutathione for Au atom anchoring and stabilization on Bi 2 WO 6 surface. Bimodal Au size distribution of highly dispersed small size clusters (0.5 ± 0.1 nm) and large size nanoparticles (6.3 ± 1.0 nm) simultaneously existed on Bi 2 WO 6 nanosheets in Bi 2 WO 6 /Au-400 °C, which were verified through high resolution transmission electron microscopy (HR-TEM). 95% of ofloxacin (OFX) was degraded over Bi 2 WO 6 /Au-400 °C in 180 min under visible light irradiation with a reaction constant of 24.5 × 10 -3 min -1 , which showed 3.0 and 2.5-fold enhancement compared with bare Bi 2 WO 6 and unimodal Bi 2 WO 6 /Au-500 °C (annealed at 500 °C, Au NPs (8.6 ± 1.0 nm)), respectively. The enhanced catalytic activity originated from the additional ROS production that initiated by photo-induced electron transported from small Au clusters to large Au NPs through the conduction band of Bi 2 WO 6 . Moreover, it still maintained a good stability after five cycling performance and the total cost of 10 g Bi 2 WO 6 /Au-400 °C was estimated to be 6.78 $. Lower-content of bimodal Au NPs decorated Bi 2 WO 6 catalyst possesses high efficiency to degrade pollutant and lower cost, which provides a promising alternative in practical environmental remediation by photocatalysis., 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 © 2020 Elsevier Ltd. All rights reserved.)

In this study, an efficient and reusable heterogeneous Fenton catalyst Fe 3 O 4 @S-doped ZnO magnetic composite was synthesized for the degradation of ofloxacin (OFX) under alkaline conditions without external energy input. The Fe 3 O 4 @S-doped ZnO exhibited excellent catalytic activity toward ofloxacin degradation within 120 min. Using 0.25 g/L of catalyst and 5.0 mL/L of H 2 O 2 under optimized conditions, the catalyst was effective in pH values ranging from 5.2 to 9.0. The catalytic performance at optimal conditions was in accordance with a pseudo-first-order kinetics model. The reaction constant of Fe 3 O 4 @S-doped ZnO (0.0354 min -1 ) was three times than that of Fe 3 O 4 @ZnO (0.0124 min -1 ) under alkaline conditions (pH 8.2). The reactive oxygen species were the ·OH and O 2 ·- , with ·OH dominating in the degradation of OFX. It is proposed that the catalyst acts as a Lewis acid, creating an acidic microenvironment on the catalyst's surface and widening the pH range of the Fenton reaction to alkaline conditions. Additionally, the catalyst was stable and reusable after six cycles of use. The Fenton-like Fe 3 O 4 @S-doped ZnO catalyst overcomes the problem of the narrow pH of the reaction system, thus providing promising environmental applications., 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 © 2020 Elsevier Inc. All rights reserved.)