Heterogeneously catalyzed persulfate with a CuMgFe layered double hydroxide for the degradation of ethylbenzene

CuMgFe layered double hydroxide (CuMgFe-LDH) was successfully synthesized and characterized as an efficient catalyst of persulfate (PS) for the degradation of ethylbenzene. Under the conditions of 0.2 g L-1 CuMgFe-LDH and 4.0 mmol L-1 persulfate at pH 7.6, the degradation efficiency of 0.08 mmol L-1 ethylbenzene was 93.7% with TOC removal efficiency of 65.2% in 24 h, and the concentration of Cu leached into the solution was as low as 0.095 mg L-1 after the reaction. The reuse of CuMgFe-LDH showed that the catalyst was highly stable after 5 recycles. Electron Spin Resonance (ESR) test and free radical quenching experiment indicated that SO4 center dot- and (OH)-O-center dot radicals were the dominant species accounted for the degradation of ethylbenzene in the CuMgFe-LDH/persulfate system. Catalytic mechanism of the formation of a complex of equivalent to Cu(II)-O3SOOSO32- and the subsequent redox cycle of Cu(II)/Cu(III) accounted for the generation of radicals was proposed. (C) 2017 Elsevier B.V. All rights reserved.