Adsorption of lindane as an organo-chlorine pesticide from aqueous solutions by mineral sand

Introduction: Pesticide including lindane has been extensively applied in agriculture as insecticide. It is considered as one of the most significant organic pollutants that have reasoned environmental pollution especially surface and ground waters. In the present study, mineral sand, as a media of slow sand filtration in water treatment, was used to remove lindane from aqueous solutions. Materials and methods: This study was carried out in batch mode. The influences of various parameters such as contact time, pH, lindane content and solution ion strength were investigated on the sorption process. The isotherm and kinetics of the sorption was also determined by the research. Results: The maximum removal efficiency of lindane by sand was achieved at the contact time and pH of 150 min and 4, respectively. The removal efficiency of lindane at abovementioned condition was (28.86% equal to 2.88 μg/g) in the concentration of 100 μg/L. The results of various isotherms and kinetics models analysis also showed that the adsorption process described well by the Freundlich isotherm and pseudo-first-order kinetics models, respectively. Addition of the salt to lindane solution increased the removal efficiency to about 3.5 times. Conclusion: This study showed that the sorption is considered as one of the major parameters of mineral sand as main media in sand filtration of water treatment plant.