Degradation of high-chemical oxygen demand concentration pesticide wastewater by 3D electrocatalytic oxidation

Abstract

The treatment of difficult biodegradable industrial wastewater by electrocatalytic oxidation technology has positive significance for the prevention and control of industrial pollution. In this study, particle electrode Ti–Ag/γ-Al2O3 was prepared and used as a catalyst in the 3D electrocatalytic oxidation reaction system for pretreatment of high-chemical oxygen demand (COD) concentration pesticide wastewater. Electrolysis conditions for high-COD concentration pesticide wastewater were discussed and optimized, and single-factor experiment results showed that the maximum COD removal rate was 82.50% with an energy consumption of 10.91 (kW h) kg−1 COD at conductivity of 4000 μS cm−1, current density of 30 mA cm−2, initial pH of 2.0, electrode distance of 3.0 cm, air flow of 3.0 L min−1, and filling proportion of 50.0%. The UV–visible absorption spectrum analysis of pesticide wastewater at different electrolysis times showed that the organic macromolecules containing long-chain, heterocyclic, and other structures were degraded into small molecular organic compounds. After the 3D electrocatalytic oxidation reaction, the BOD5/COD value of pesticide wastewater increased from 0.041 to 0.308, indicating that the biodegradability of the pesticide wastewater was improved significantly.