The development and assessment of organobentonite composite materials for use in the removal of organochlorine pesticides in water

Abstract

This work describes the modification of bentonite to organobentonites in order to change its property from hydrophilic to organophilic to enhance its capability in adsorbing organochlorine pesticides from water. Bentonite was modified by adding quarternary ammonium cations through an ion exchange technique. The organochlorine pesticides studied were heptachlor, aldrin, dieldrin, DDT and mirex. The modified bentonites were characterized using Fourier transform infrared (FTIR), X-ray diffraction (XRD), carbon, and hydrogen and nitrogen analyzer (CHN). Gas chromatography-mass selective detector (GC-MSD) was used to determine the concentration of organochlorine pesticides while evaluating the efficiencies of organobentonites in removing the pesticides from water. Bentonite modified with dodecyltrimethylammonium (DDTMA) has the highest capacity in removing pesticides. DDTMA-bentonite with the lowest amount of quarternary ammonium cations (0.710%) was capable of removing very high percentage of pesticides (95.96±2.50% of aldrin) after 30 minutes of water treatment duration. The optimized treatment conditions of 30 minutes of treatment duration, 0.2000 g of DDTMA-bentonite and 50 rpm of shaking speed were applied throughout this work on the samples obtained from the locations suspected of containing organochlorine pesticides