Electrochemical activation of peroxydisulfate by Ti/IrTaO2 anode for quick degradation of xanthate

Abstract

High concentrations of residual xanthate in mineral processing wastewater often limit the reuse of tailing water. Targeted removal of xanthate is an effective strategy for improving the tailing water recycling rate. In this study, the degradation efficiency and mechanism of sodium ethyl xanthate (SEX) in an electroactivated peroxydisulfate (EAPDS) system were investigated systematically. To avoid the influence of co-existing organic and inorganic matters in real flotation wastewater, we used simulated SEX wastewater to conduct the efficiency and mechanism investigation. A significant synergistic effect between electrocatalysis and peroxydisulfate was observed during the SEX decomposition. When the initial concentration of SEX was 200 mg/L, it achieved 100% removal rate only in 30 min with PDS dosage of 5 mM at current density of 10 mA/cm2. The introduction of peroxydisulfate boosted the removal efficiency six-fold compared to electrocatalysis alone. UV-Vis spectroscopy and GC-MS analyses revealed that the intermediate products of SEX were C2H5OH and CS2. The reactive oxygen species induced in the EAPDS were identified using a series of detection methods. •OH, 1O2, h+, O2•− and electron transportation process (ETP) all contributed to SEX removal. The degradation mechanism in the EAPDS system was proposed based on the analysis of the reactive oxygen species and products. Application to real flotation wastewater was attempted as well. The effects of different operating conditions were also evaluated, including pH, coexisting anions, PDS dosage, and current density. This study provides a new approach for the rapid removal of residual xanthates from mineral processing wastewater.