Activation mechanism of CoFe2O4 nanocatalysts on different oxidants and degradation efficiency of butyl xanthate

Abstract

Owing to the technological limitations associated with beneficiation technology, large amounts of flotation reagents remain in mineral processing wastewater, which is extremely detrimental to humans and the environment. In addition, direct reuse of mineral processing wastewater will adversely affect the entire mine water system. Efficient treatment of residual butyl xanthate from tailing wastewater has recently attracted increasing interest. In this study, we compared the degradation efficiencies of cobalt iron oxide (CoFe2O4) nanoparticles assisted by sulfite-activated advanced processes and persulfate (PDS) and peroxymonosulfate (PMS) advanced oxidation processes on butyl xanthate (BX) for the first time and explored possible reaction mechanisms in various systems. We conducted comprehensive experiments on the acid/alkali washed catalysts using oxidizing agents, obtaining catalysts best adapted to three degradation systems. Results of batch experiments indicated that the BX degradation rate for all the three systems exceeded 95 % within 60 min under their respective optimal conditions and that the best total organic carbon content (TOC) removal rate for these systems was 85.79 %. The effects of key factors, such as catalyst dosage, oxidant dosage, solution pH, and coexisting ions, on BX degradation were investigated. Furthermore, the active free radicals that played a major role in each system were detected via electron paramagnetic resonance (EPR). EPR results indicated that SO3·− and ·O2− were the main active species of the CoFe2O4/sodium sulfite system, ·OH and ·O2− participated in the degradation of BX in the CoFe2O4/PDS system, and ·O2− was present in the CoFe2O4/PMS system. Thus, this study promotes the application of CoFe2O4 with magnetism as a catalyst in wastewater treatment and provides new insights into the effective treatment of organic pollutants in tailing wastewater.