RESUMEN

Benzoquinone (BQ) is of great significance for enhancement of contaminants degradation in the homogeneous oxidation system of peroxymonosulfate (PMS). However, the role of BQ in the heterogeneous activation of PMS for contaminants oxidation is still not clear. Herein, this work reported that the addition of BQ into the Fe3S4/PMS system could effectively enhance the degradation and mineralization of bisphenol A (BPA). Mechanistic study uncovered that the BQ and PMS would form active complexes (BQ-PMS*) on the surface of Fe3S4 and the excited BQ-PMS* can oxidize the BPA. To be specific, the electron of BPA was extracted by BQ-PMS* and then transfer to the surface of Fe3S4. The surface electron can induce the change of valence state of S and Fe elements, which can trigger the degradation of BPA and inhibit the decomposition of BQ itself. To the best of our knowledge, it is the first time to unveil the positive role of BQ in the heterogeneous activation of PMS, which may shed new light on the establishment of high-efficient PMS-based oxidation technology for remediation of organic pollutant.

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RESUMEN

Catalytic membrane can achieve sieving separation and advanced oxidation simultaneously, which can improve the effluent water quality while reducing membrane fouling. In this study, the catalytic membranes (M2+Al@AM) were fabricated by loading different binary layered metal oxides (M2+Al-LMO: MnAl-LMO, CuAl-LMO and CoAl-LMO) on alumina ceramic substrate membranes (AM) via vacuum filtration followed by calcination process. The performance of the catalytic membranes was investigated by filtering actual surface water. It was found that the presence of peroxymonosulfate (PMS) could mitigate membrane fouling effectively, as evidenced by the increase of normalized flux from 0.28 to 0.62 in CoAl@AM/PMS system, from 0.25 to 0.52 in CuAl@AM/PMS system, and from 0.22 to 0.31 in MnAl@AM/PMS system, respectively. Correspondingly, the CoAl@AM exhibited the highest removal for UV254, TOC and fluorescent components in the surface water, followed by CuAl@AM and MnAl@AM. Quenching effect of phenol and furfuryl alcohol proposed the surface-bound radicals and singlet oxygen were the major reactive oxygen species in the M2+Al@AM/PMS systems. Interface free energy calculations confirmed the in-situ PMS activation could enhance the repulsive interactions between NOM and the membranes, thus mitigating membrane fouling. This work provides an original but simple strategy for catalytic ceramic membrane preparation and new insights into the mechanism of membrane fouling mitigation in catalytic membrane system.

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RESUMEN

In this study, a series of aluminum-based layered metal oxide with various divalent metals (M2+Al-LMOs) were prepared and employed in activation of peroxymonosulfate (PMS) for bisphenol A (BPA) degradation. The BPA removal rates of M2+Al-LMOs were ordered as: CoAl(100%) > MnAl(75.6%) > CuAl(63.2%) > NiAl(9.0%) > MgAl = ZnAl-LMO(0%). CoAl-LMO showed the highest kinetic constant (k = 1.329 µmol-1gcat-1s-1), which was 3.95 times of MnAl-LMO, 5.36 times of CuAl-LMO, 88.6 times of NiAl-LMO and 443 times of MgAl-LMO and ZnAl-LMO, respectively, and also exhibited the highest TOC removal rate (83.3%). The surface-bound sulfate radical (SO4·-) and singlet oxygen (1O2) were elucidated as the dominant reactive oxygen species (ROS) for BPA degradation. The M2+Al-LMOs/PMS system not only displayed wide applicability in different pH and inorganic anions environments, but also had excellent stability and reusability. This work provides a novel family of M2+Al-LMOs to activate PMS for water treatment.

RESUMEN

Selective adsorption and regeneration of adsorbents are great challenges for fluoride removal in drinking water. In this study, a NiAl-layered metal oxide (NiAl-LMO) electrode was successfully prepared and used as an electro-adsorption electrode. With its structural memory effect for anions and high specific capacitance of 575 F·g-1, the NiAl-LMO electrode exhibits capacitive deionization performance. The maximum adsorption capacity of F- by the electrode reached 49.28 mg/g, which was 4 times that of Cl- and 2 times that of SO42-, respectively. The good selectivity for F- electrosorption was ascribed to the high electronegativity of F- and the complexation between F- and hydroxyl aluminum groups. The electrode material has good stability and can be regenerated easily by applying a reverse voltage. After 10 cycles, the F- adsorption rate by the NiAl-LMO electrode was 94. 4% of the initial adsorption rate. The applied voltage enhanced the selectivity of F- adsorption by the NiAl-LMO electrode, and this electrosorption process was mainly dominated by electrical double layer adsorption. Under the conditions of 1.0 V and pH 7, the electrode showed a maximum adsorption efficiency of 73.5%.