Electrochemical removal of the insecticide imidacloprid from water on a boron-doped diamond and Ta/PbO2 anodes using anodic oxidation process

Abstract

The removal of pesticides from water is a major environmental concern. This study investigates the electrochemical removal of the insecticide imidacloprid (IMD) from aqueous solutions on a boron-doped diamond (BDD) and Ta/PbO2 anodes under galvanostatic electrolysis. The influence of operating parameters, such as applied current density (50–100 mA cm−2), initial chemical oxygen demand COD (0) (281–953 mg L−1), temperature (25–65 °C) and pH (3.0–10.0) on COD and instantaneous current efficiency (ICE), was studied using the BDD electrode. The degradation efficiency of IMD increased by increasing current density and temperature, but noticeably decreased by the increase of initial pH value and initial concentration of IMD. The COD decay follows a pseudo-first-order kinetic, and the process was under mass transport control. COD removal reaches 90% when using an apparent current density of 100 mA cm−2, initial COD of 953 mg L−1, pH of 3.0 and at 25 °C after 4.5 h electrolysis time. Compared with Ta/PbO2, BDD anode has shown better performance and rapidity in the COD removal using the same electrolysis device.