Highly efficient activation of peroxymonosulfate by illite-based ultrafine cobalt oxide for the degradation of polyvinyl alcohol

Abstract

A catalyst was prepared using illite coated with Co3O4 to activate peroxymonosulfate (PMS) for polyvinyl alcohol (PVA) degradation. The variance of valence of specific elements, functional groups, surface morphology, and pore structure of fresh illite, fresh Co3O4@illite and used Co3O4@illite were also investigated, reflecting the excellent stability of the Co3O4@illite catalyst. Degradation experiments confirmed that OH∙, 1O2, and SO4∙- produced by oxygen cavitation reaction acted a significant part in PVA degradation. Moreover, when initial pH = 7, catalyst dosage = 2.0 g/L, PMS concentration = 40 g/L, T = 298 K, the best PVA removal efficiency was got. Also, the adding of H2PO4− and Cl− concentration could inhibit the degradation of PVA at first and then promoted, while the addition of other ions (i.e., HCO3− and CO32−) always inhibited degradation reaction. The transformation products on the possible degradation pathway of PVA were then proposed. The strategy of this study gave a new perspective for the coming design of the natural-mineral-based catalysts to effectively treat waste through the Fenton like processes.