Efficiency of Electrochemical Process in Removal of Imidacloprid from Aqueous Solutions: Effect of Type and Arrangement of Electrodes

Background and Imidacloprid (IM) is a systemic insecticide that is widely used to control a large number of pests in agriculture. It has toxic effects, therefore, it should be removed using appropriate methods. The aim of this study was to evaluate the efficiency of electrochemical degradation process to remove IM from aqueous solutions.
In this experiment, a glass reactor and different combinations of electrodes were used to assess process efficiency in batch mode. The effects of various parameters were studied to determine the optimum conditions. We used the combinations of lead and stainless steel electrodes as the anode and the cathode, respectively. Then, under optimum conditions, the efficiencies of other electrodes including copper, iron, aluminum, steel and graphite in removal of IM were simply compared.
The analysis showed that in the optimal conditions, the maximum removal efficiency of IM and COD were 97.2% and 88.57%, respectively. The data followed the pseudo first order reaction kinetics model. Among the electrodes investigated, lead followed by copper, iron, stainless steel, graphite, and aluminum showed the highest efficiency. Fourier transform infrared spectroscopy (FTIR) analysis showed that due to IM degradation, the functional groups have been changed, and the results of GC/MS analysis confirmed the degradation of the compound to the final products.
The results indicated that electrochemical process is an effective process in Imidacloprid removal which could remove ≈ 97% of IM.