The performance of Cu-EDTA degradation by peroxymonosulfate activated by iron scraps

Abstract

The iron scraps from industrial production were used as zero valent iron（ZVI） source to activate peroxymonosulfate（PMS）. The performance of Cu-EDTA degradation by iron scraps activated PMS was studied. The effects of initial PMS concentration，iron scraps doses，pH and water matrices on the breakdown of Cu-EDTA were investigated. Then，the reactive species in iron scraps/PMS system were identified and the characterization of the iron sludge generated in the reaction process was conducted. The results showed that when the dosage of iron scraps was 10 g/L，the initial PMS concentration was 4.5 mmol/L，the removal rate of Cu was 99.64% at pH=3. The pH had no significant effect on reaction. However，the CO32- and Cl- had some inhibition effect on Cu removal，and the inhibition effect caused by former was more obvious than the latter. HA had no obvious influence on Cu removal. Scavenger experiments combined with EPR identification confirmed that SO4·- and ·OH both existed in the system and contributed to Cu-EDTA removal. The characterization of iron sludge showed that the surface of iron scraps was corroded to generate nano scale iron（hydro）oxides，which enhanced the removal of Cu.

Keywords

• advanced oxidation processes
• iron scraps
• peroxymonosulfate
• cu-edta