Heterogeneously catalyzed persulfate by CuMgFe layered double oxide for the degradation of phenol

Abstract

CuMgFe layered double oxide (CuMgFe-LDO) was successfully obtained from CuMgFe layered double hydroxide (CuMgFe-LDH) and employed to degrade phenol in the heterogeneous catalysis of persulfate (PS). The effects of CuMgFe-LDO dosage, PS concentration, initial pH (pH0) and the presence of common inorganic anions on the removal of phenol were comprehensively evaluated in this study. It was revealed that CuMgFe-LDO performed excellently in activating PS to remove phenol with a great stability under a wide range of pH0 values ranging from 5.0 to 11.0. With 0.5g/L CuMgFe-LDO and 0.5mmol/L PS at pH0 6.4, 95.3% of 0.1mmol/L phenol was removed within 30min. Based on the results of electron paramagnetic resonance (EPR) and radical quenching experiments, it was inferred that free radicals bounded to the surface of CuMgFe-LDO was the dominant oxidant for the degradation of phenol. Furthermore, p-benzoquinone was considered to be the major intermediate in the oxidation process. Finally, the CuMgFe-LDO exhibited excellent stability after 3 times recycling with the concentration of the leached copper ion at 0.19mg/L, being lower than the drinking water standard of U.S Environmental Protection Agency (1.3mg/L). The findings of the work provided a new insight into the remediation of phenol polluted water within the system of CuMgFe-LDO/PS.