Degradation of 4‐chlorophenol by BM Fe/Cu‐O 2 system: The symbiosis of · O 2 - and · OH radicals

In this study, Fe/Cu bimetal composite was prepared by high‐energy ball milling ( BM ) method for the removal of refractory organics. The BM Fe/Cu bimetal was characterized by SEM ‐ EDS , XRD , and XPS . Evenly distributed Fe and Cu was observed in the EDS mapping. In contrasting experiments, the removal rate of 4‐chlorophenol (4‐ CP ) by BM Fe/Cu materials was about 10‐fold faster than that by chemical substitution deposition ( CSD ) of Fe/Cu material. Complete 4‐ CP removal and 66.7% of total organic carbon ( TOC ) mineralization in the BM Fe/Cu–O 2 system were achieved. Dissolved oxygen plays a crucial role for 4‐ CP degradation through the in situ generation of reactive oxygen species (ROS) such as H 2 O 2 , · OH , and · O 2 -via oxygen activation reactions. The predominant reactive radicals were identified to be · O 2 -and · OH through ESR technique and inhibition experiments. The coexistence of oxidation and reduction of 4‐ CP in the BM Fe/Cu‐O 2 system was proposed. Practitioner points 4‐ CP removal rate by BM Fe/Cu is 10‐fold faster than that by CSD Fe/Cu at the same conditions. Complete 4‐ CP removal and 66.7% of TOC reduction were achieved. All three ROS including ·OH, · O 2 - , and H 2 O 2 coexisted in the BM Fe/Cu‐O 2 system. A harmonious coexistence of oxidation and reduction mechanism was proposed.