Efficient removal of aniline by micro-scale zinc-copper (mZn/Cu) bimetallic particles in acidic solution: An oxidation degradation mechanism via radicals.

Abstract

Micro-scale zinc-copper (mZn/Cu) bimetallic particles were prepared via precipitating Cu on the surface of Zn and were for the first time applied in the aniline degradation. The results showed that the degradation efficiency of aniline was greatly related to the theoretical Cu mass loading and the initial pH. The optimal Cu loading and initial pH for the destruction of aniline were determined as 60.45 wt% and 3, respectively. To further assess the high reactivity of mZn/Cu, the removal of aniline and total organic carbon (TOC) was investigated in different systems. The degradation of aniline by mZn, mCu, and mZn + mCu was <5% within 75 min. However, 97% of aniline (10 mg L-1) was decomposed and 47% of TOC was removed by mZn/Cu, both of which were more than three times as much as those by mFe/Cu. The mechanism investigations revealed that •OH radicals engendered from the reaction process are responsible for the rapid oxidative degradation of aniline. Furthermore, based on the analyses of the intermediates via LC-MS, the possible degradation pathways of aniline were proposed. Our findings suggested that mZn/Cu is a potential approach for aniline removal, which is different from the other bimetallic systems reported in the previous studies mainly as the reductive degradation.