Efficient activation of persulfate by metallic sulfide mineral for the efficient removal of pesticides: Performance, radical generation and mechanism.

In current years, the harm of pesticide residual pollution to environmental ecology and human health has obtained increasing attention. Hydroxylamine (HA) promoted activation of persulfate (PS) by the natural metallic sulfide mineral chalcopyrite (CuFeS 2) for the removal of pesticide chlorpyrifos (CPF) and imidacloprid (IMP) in water had been systematically investigated in this study. Experimental results showed that HA could greatly accelerate the regeneration of Cu2+ and Fe3+ in solutions for PS decomposition. Nearly 99% of CPF removal by CuFeS 2 /PS/HA process was achieved within 80 min under optimal conditions. The decomposition of PS in the CuFeS 2 /PS/HA process was higher than that in the CuFeS 2 /PS process. Several coexisting cations (ie., Ca2+, Mg2+ and Al3+) and anions (ie., HCO 3 − and HPO 4 2−) presented different levels of negative effects on CPF removal. Both HO• and SO 4 •− were generated in the CuFeS 2 /PS/HA process, and HO• might be the main reactive species responsible for the removal of CPF. The synchronized removal of CPF and IMP by CuFeS 2 /PS/HA process had been successfully achieved under certain conditions. The possible pathways of CPF degradation and enhanced mechanism for both CPF and IMP removal by CuFeS 2 /PS/HA process were thereby proposed. This study highlights the applications of CuFeS 2 /PS/HA process for the remediation of multiple pesticides-polluted wastewaters. [Display omitted] • HA accelerated the regeneration of Cu2+ and Fe3+ for PS decomposition. • HO.• might be the main reactive species responsible for the removal of CPF. • Two possible degradation pathways of CPF by CuFeS 2 /PS/HA process proposed. • About 90% of both CPF and IMP removal by CuFeS 2 /PS/HA process was achieved. • Enhanced mechanism of CPF and IMP removal by CuFeS 2 /PS/HA process was proposed. [ABSTRACT FROM AUTHOR]