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Developing an efficient, low-cost and stable catalyst to activate peroxymonosulfate (PMS) for pollutant degradation is crucial in environmental remediation. Herein, Co1Fe1 layered double hydroxide (Co1Fe1-LDH) was in situ loaded on biochar (BC) derived from rape straw for sulfamethoxazole (SMX) degradation via activating PMS. It could be found that the optimal catalyst (BC/Co1Fe1-LDH-4) exhibited the highest SMX degradation efficiency of 94.8% within 5 min reaction, far more than pristine Co1Fe1-LDH (58.5%), which might be ascribed to the synergistic effects between Co1Fe1-LDH and BC during the reaction. For one thing, BC itself participated in the catalytic degradation reaction as an activator and made the catalyst have excellent adsorption and degradation performance. For another, BC as a carrier not only effectively inhibited the agglomeration of Co1Fe1-LDH to increase the active sites, but also accelerated the Co2+/Co3+ and Fe2+/Fe3+ cycles to reduce the leaching of metal ions. Meanwhile the leaching of trace metal ions also promoted the degradation of SMX to a certain extent, indicating that the catalytic mechanism was a combination of homogeneous and heterogeneous catalysis, and the latter was dominant. The quenching trials, electron paramagnetic resonance (EPR) and electrochemical measurements implied that the radical and non-radical processes were involved in the reaction, where SO4˙−, ˙OH and O2˙− were the main radical species to drive the radical process, and 1O2 and direct electron transfer were responsible for the non-radical process. In addition, the possible SMX degradation pathways were reasonably proposed by high-performance liquid chromatography-mass spectrometry (HPLC-MS) tests and the SMX mineralization degree was provided through total organic carbon (TOC) measurements. This present work provides new insight into the construction of highly efficient PMS activation catalysts for environmental wastewater treatment. [ABSTRACT FROM AUTHOR]

The magnetic CuFeO 2 anchored on nitrogen-doped porous carbon (CuFeO 2 /NC) hybrid catalysts were further synthesized via hydrothermal reaction without the addition of a chemical reductant. The systematic CuFeO 2 /NC with larger specific surface areas (SSAs) and abundant active sites exhibited strong adsorption ability and great catalytic performance towards activating peroxymonosulfate (PMS) for sulfamethoxazole (SMX) removal. It was noted that 18 mg/L SMX was completely removed after 40 min of pre-adsorption and 30 min of oxidative degradation in CuFeO 2 /NC and PMS system. The degradation rate constant (k) was calculated by fitting as 0.166 min−1, being about 7.9 times that in the CuFeO 2 and PMS system (0.021 min−1). The SO 4 ·-,·OH, and 1O 2 as the dominant reactive oxygen species (ROSs) contributed to sulfamethoxazole degradation. The N species, active oxygen and the redox cycles of Cu(Ⅱ)/Cu(Ⅰ) and Fe(Ⅲ)/Fe(Ⅱ) were confirmed to play a vital role in the activation of PMS for the generation of ROSs. Based on the LC-MS analysis, the possible degradation routes of SMX in the PMS activation system by CuFeO 2 /NC were proposed. [Display omitted] • CuFeO 2 /NC hybrid catalysts were synthesized successfully without the addition of a chemical reductant. • CuFeO 2 /NC has excellent adsorption and catalytic capabilities for SMX removal. • The mechanism of PMS activation by CuFeO 2 /NC is elucidated in detail. • The degradation pathway of SMX is proposed in CuFeO 2 /NC and PMS system. [ABSTRACT FROM AUTHOR]

[Display omitted] • Cu–Mn spinel oxides/N-C (CMO/NC) was successfully synthesized by a simple and green method. • Efficient removal and deep mineralization of BPA was achieved in the CMO/NC/PMS system. • Synergistic effects were verified between metals Cu and Mn and between CMO and N-C support. • The catalytic mechanism, degradation pathways and intermediate toxicity were proposed. • The CMO/NC/PMS system had broad application prospects. Fenton-like technology can efficiently remove recalcitrant pollutants, but developing catalytic oxidation system for deep mineralization of pollutants remains a challenge. Therefore, Cu–Mn spinel oxide nanospheres anchored N-doped carbon (CMO/NC) was prepared by a one-step calcination method and used to activate peroxymonosulfate (PMS) for efficient mineralization of bisphenol A (BPA). With the use of 0.5 g/L CMO/NC and 0.2 g/L PMS, the added BPA (50 mg/L) was completely degraded and deeply mineralized (nearly 95.2 %) in 9 min. The apparent first-order degradation rate constant k was 0.557 min−1, which was 61.9, 6.2 and 2.5 times than those in the systems of N-C/PMS (0.009 min−1), CuO/NC/PMS (0.09 min−1) and Mn 3 O 4 /NC/PMS (0.22 min−1). A comparison between the catalytic performances of CMO/NC catalysts prepared by changing the dosage of urea confirmed the catalysis synergism between Cu–Mn spinel oxides and N-C. A further comparison between the catalytic performances of CMO/NC catalysts prepared by varying the Cu/Mn molar ratio of the precursors showed that the synergy between Cu and Mn sites promoted the catalytic activity, with a synergistic effect factor of 1.8. XPS and H 2 -TPR characterizations proved that strong Cu-Mn interaction caused Mn species easier to donate electrons to PMS and Cu species easier to accept electrons from PMS. The degradation pathway and intermediate toxicity suggested that the system did not produce secondary pollution. Based on the results of EPR and capture experiments confirming that 1O 2 was the major active species, a mechanism on PMS activation was proposed. Through investigations of continuous flow BPA wastewater removal, the influence of coexisting anions and catalyst cycling stability, it was clearly demonstrated that the present system had broad application prospects. [ABSTRACT FROM AUTHOR]

A novel CuO–Fe 3 O 4 encapsulated in the carbon framework with abundant oxygen vacancies (CuO–Fe 3 O 4 @C) was successfully prepared by thermal conversion of Cu(OAc) 2 /Fe-metal organic framework. The as-prepared catalyst exhibited excellent peroxymonosulfate (PMS) activation performance, good recyclability and fast magnetic separation. Under optimal conditions, the added BPA (60 mg/L) could be completely removed by CuO–Fe 3 O 4 @C/PMS system within 15 min with the degradation rate constant (k) of 0.32 min−1, being 10.3 and 246.2 times that in CuO/PMS (0.031min−1) and Fe 3 O 4 /PMS (0.0013 min−1) system. A deep mineralization rate of BPA (＞80%) was achieved within 60 min. The results demonstrated the synergistic effect of bimetallic clusters, oxygen vacancies and carbon framework was a key benefit for the exposure of more active sites, the electron donor capacity and the mass transfer of substrates, thereby promoting the decomposition of BPA. Capture experiments and EPR indicated that 1O 2 was the predominant reactive oxygen species (ROSs). The degradation routes of BPA and the activation mechanism of PMS were proposed. This study offers an opportunity to develop promising MOFs-derived hybrid catalysts with tailored structures and properties for the practical application of SR-AOPs. [Display omitted] • Magnetic CuO–Fe 3 O 4 @C with abundant oxygen vacancies was synthesized successfully. • CuO–Fe 3 O 4 @C has excellent catalytic performance, good stability and strong mineralization ability for BPA removal. • The activation mechanism of PMS using CuO–Fe 3 O 4 @C were confirmed. [ABSTRACT FROM AUTHOR]