Organophosphorus Pesticide Chelation by Modified Pod Shells – Batch Equilibration and Isothermal Studies

Extensive loads of pesticides are utilized to increase the crop productivity in modern agricultural practices. Slow degradation of pesticides into the environment and extensive or inappropriate use by farmers can lead to contamination of water, soil, air, several types of crops and in turn human beings. Malathion pesticide has been widely used as fumigant, in agriculture and in residential landscapes to replace more toxic organochlorine pesticides, even otherwise result in a serious setback to human health causing skin and nervous defects. Adsorption technique is one of the most intensively availed and reliable method adopted due to its ease of operation, non-energy intensive and high removal competence of organic pollutants, like pesticides. Delonix regia pod shells (DRPS), an eco-based material is employed to chelate malathion from aqueous media through batch mode under varying operational factors, namely, pH (3-11), initial malathion concentration (50-300 mg/L), DRPS dosage (50-250 mg), contact time (10-60 min) and temperature (293-333 K). Optical microscope, FTIR, SEM are utilized to characterize the selected sorbent’s nature. Isothermal data fitted well with the Langmuir plot in preference to Freundlich plot. From the observations made, DRPS is found to be a promising ecofriendly, economically viable material for the sequestration of malathion.