Electrocatalytic oxidation of PCP-Na by a novel nano-PbO2 anode: degradation mechanism and toxicity assessment

Abstract

This study aims at investigating the electrocatalytic oxidation of sodium pentachlorophenate (PCP-Na) using a novel nano-PbO2 powder anode. The nano-PbO2 powder (marked as HL-PbO2) was prepared by a simple hydrolysis process, and hydrothermal treatment was followed to improve the activity of HL-PbO2. The HL-PbO2 treated for 24h by hydrothermal process (HL/HT-PbO2-24) was confirmed to possess higher crystallinity, higher oxygen evolution potential, and more active sites, resulting in stronger OH radical generation capacity and higher electrochemical activity. Compared with conventional electrodeposited PbO2 (ED-PbO2) anode, the HL/HT-PbO2-24 anode showed higher PCP-Na degradation rate. Under the same operating conditions, the mineralization current efficiency at HL/HT-PbO2-24 was 2.7 times than that at ED-PbO2. Five intermediates were detected in PCP-Na degradation solution and possible degradation mechanism of PCP-Na was discussed. In addition, the acute toxicity of PCP-Na degradation solution to zebrafish embryos and the oxidative stress induced in zebrafish embryos/larvae were studied to evaluate the ecological security of electrocatalytic oxidation of PCP-Na.