Optimization and evaluation of malathion removal by electrocoagulation process and sludge management

Abstract

In this research work, the effect of various independent operating variables on the removal of malathion pesticide by electrocoagulation (EC) process was evaluated by single variable multivariable optimization. The various operating variables selected were reaction time (40–75 min), pH (6−9), applied voltage (8–20 V), and amount of electrolyte (8–20 ml). The effect of aluminium and iron electrode on the removal efficiency were compared and aluminium was found to be better performed, further RSM studies were carried out with this electrode. The optimum operational conditions were achieved as reaction time of 75 min, solution pH of 7.5, applied voltage of 15 V and the electrolyte addition of 15 ml. A removal efficiency of 85% was obtained at an energy consumption of kWh. by incorporating the interaction effects of different optimized variables. In this paper, the facts associated with the removal mechanism and the operational cost analyses were performed. The reaction behaviour has been discussed through mini reaction pathways and results were supported by SEM, EDAX and FTIR characterizations. End products of the EC process are the dissociated pesticide with metal hydroxide particles. This study also discusses the disposal of solid sludge with economic and environmental benefits used as admixture in the stabilization of expansive soils. The sludge fused soil properties were improved when compared to the plain soil properties and the classification of soil were changed from moderate to stiff soil. This indicates the possible use of sludge as stabilizing agent subsequently and it can address the disposal and environment concern related to the end products of EC process in economic way.Effect of this soil on the ground water pollution was also investigated.