Ultrasound irritation enhanced activation of peroxymonosulfate with fe0 for humic acid removal: Less formation of fe-ha complex

Abstract

Commercial zero-valent iron (Fe0) particle was used as peroxymonosulfate (PMS) activator with the assistance of ultrasound (US) irritation for humic acid (HA) removal in this study. 100% HA removal rate was obtained in the Fe0/PMS/US system under the optimal experimental condition. The higher Fe0 dosage, neutral pH and optimal PMS concentration facilitated the HA removal. The use of US reduced the generation of HA-Fe complex and improved the release of Fe in the Fe0/PMS/US for HA removal. The reaction process of HA removal was fitted with the first-order kinetic and the US exhibited obvious synergic effect for HA removal. The non-thermal effect of US was the main reason for enhancing HA removal. Sulfate radicals (SO4 •−), hydroxyl radicals (•OH), Fe(VI) and singlet oxygen (1O2) were produced in the reaction and1O2 was the dominant species according to the result of scavenging tests and electron paramagnetic resonance tests. This study indicates the Fe0/PMS/US is an available and effective technology for HA removal.