A GREEN TECHNOLOGY FOR THE REMOVAL OF PENDIMETHALIN FROM AQUEOUS SYSTEM USING ADSORPTION TECHNIQUEPRANEESH M., BABU V. AND ANU GOPINATH
Pendimethalin (N-(1-ethylpropyl)-2,6-dinitro-3,4-xylidine) is a selective herbicide comes under dinitroaniline class which is used to control most of the annual grasses and many annual broad leaved weeds. Unlike other dinitroaniline herbicides, Pendimethalin shows persistence in soil up to 50 weeks. Among other water treatment techniques, adsorption processes are important wastewater treatment techniques because of its cost-effectiveness and availability of adsorbents. In this study adsorbing property of natural adsorbents like granular activated carbon, powdered activated carbon and carbon coated chitosan film were made use for the removal of Pendimethalin from the aqueous system. From adsorption studies it could be observed that powdered activated carbon shows better adsorption capacity compared to other adsorbents. The adsorption capacities of the absorbents used for the study are in the order of Powdered activated carbon (98% irrespective of pH) > carbon-coated chitosan film (91% at pH 7) > Chitosan (70% at pH 2) > Granular activated carbon (44.9% at pH7). To overcome the practical difficulties in the separation of powdered activated carbon from treated water, carbon-coated chitosan was used as an adsorbent for kinetics and adsorption isotherm studies. Isotherm studies confirm that adsorption processes of Pendimethalin over carbon-coated chitosan film favors Freundlich Adsorption Isotherm (multilayer adsorption). It was found that pseudo second order equation provided good correlation with experimental data for the adsorption of Pendimethalin over carbon-coated chitosan film.