Optimization of electro-Fenton process for effective degradation of organochlorine pesticide lindane

Lindane is an organochlorine pesticide broadly used in the last decades. It is persistent and recalcitrant in aquatic environments and difficult to biodegrade. This study is focused on the complete degradation of lindane by an electrochemical advanced oxidation process, the electro-Fenton (EF) process, using a BDD anode and carbon felt (CF) cathode. The influence of the main operating parameters, i.e., applied current intensity (50-1000 mA), catalyst concentration (0.0-0.5 mM) and initial pollutant concentration (5.0-10.0 mg L-1) has been investigated and optimized. The applied current plays a determinant role both in oxidation of lindane and mineralization of its aqueous solution. Taking into account the mineralization current efficiency (MCE) and the specific energy consumption (EC), the applied current of 400 mA was found to be the most convenient value. Catalyst (Fe2+) concentration as low as 0.05 mM, promotes efficiently H2O2 decomposition into hydroxyl radicals improving the efficiency of the process and minimizing the involvement of parasitic reactions. The initial pollutant concentration does not affect the performance of the process. At the optimum operating conditions, the complete degradation of 10 mg L-1 lindane solution and 80% of TOC removal were achieved at 15 min and 4 h, respectively.