FeS assisted degradation of atrazine by bentonite-supported nZVI coupling with hydrogen peroxide process in water: Performance and mechanism.

In this study, bentonite-supported nZVI (B-nZVI) was used as a catalyst to activate HO for atrazine (ATZ) degradation in the presence of FeS. Results indicated that ATZ degradation by B-nZVI/HO process was significantly enhanced when FeS was introduced, and nearly 98% of ATZ was degraded by B-nZVI/FeS/HO process within 60 min under the optimum conditions. ATZ degradation of B-nZVI/FeS/HO process was much higher than the sum of B-nZVI and FeS/HO processes. The presence of HCO, PO and F exhibited significant negative effects on the ATZ degradation, whereas both Cu and Ni exhibited positive effects on that. Both citric acid (CA) and ethylenediaminetetraacetic acid (EDTA) with lower concentration enhanced ATZ degradation rate, but significant suppression effects on that with higher concentration. The degradation of ATZ and 2,4-Dichlorophenol (2,4-DCP) could be simultaneously achieved in B-nZVI/FeS/HO process under certain conditions. High soluble Fe induced an excellent decomposition of HO by B-nZVI and FeS. OH was dominant radical, and contributed to nearly 86% of the overall ATZ removal. A total of five intermediate products of ATZ were identified, and ATZ degradation was achieved via de-alkylation and hydroxylation processes. An enhanced reaction mechanism for ATZ degradation by B-nZVI/FeS/HO process was proposed, and B-nZVI/FeS/HO process exhibited an excellect catalytic performance within four successive runs.