Peroxymonosulfate activation by hydroxylamine-drinking water treatment residuals for the degradation of atrazine

Abstract

Drinking water treatment residuals (WTRs) have been applied in organic pollutants degradation in water by generating reactive oxygen species from peroxymonosulfate (PMS), however, the slow transformation of Fe(III) to Fe(II) may limit its widespread application. Hydroxylamine (HA) was introduced into the system to enhance the degradation efficiency of atrazine (ATZ) and several key reaction parameters (HA concentration, PMS concentration, pH and temperature) were concerned to study their influence on ATZ degradation. The results revealed that ATZ degradation efficiency was enhanced in the HA/WTRs/PMS system. Effects of some basic inorganic ions (Cl−, SO42− and NO3−) and natural organic matter on ATZ degradation were investigated and results showed that both have an inhibitory effect on ATZ removal. In addition to the reduction role, HA can also react directly with PMS to produce free radicals that helpful for ATZ degradation. Sulfate radical and hydroxyl radicals were generated and sulfate radical was identified as primary radicals in the HA/WTRs/PMS system by alcohol quenching experiments. Moreover, the HA/WTRs/PMS system also showed good performance for ATZ degradation in authentic water like surface water and groundwater. Introduction of hydroxylamine into the system may promote organic pollutant degradation and use of WTRs as an iron source for PMS activation provides new ideas for sludge treatment.