The effects of zeolite x and y on degradation kinetics of P, P'-DICHLORODIPI-IENYLYTRICIILOROETHANE (DOT) in natural water

Abstract

The study was on degradation kinetics of pesticides in water by zeolites. Pesticides are never target specific and as such, aerial dissipation of pesticides is potentially \ hazardous to man and environmental biodiversity. Pesticide residues are in addition dispersed in the environment mostly through agricultural runoff, industrial and domestic effluent. The use of pesticides inevitably leaves behind residues in main domestic water sources. Man thus has had adverse health effects through the consumption of water from these sources. Current water purification in use lacks the capacity to get rid of most pestic ides and their degradation products. Research done in Belgrade - Montenegro had reported that the presence of some zeolites in the wastewater enhances the degradation of pesticide contaminants. However data on degradation kinetics of pesticides in the presence of zeolites is lacking, as there is no work documented. The study of this pesticides i.e., organochlorides as represented by DOT, was therefore justified as the results have proved that zeolite is capable of enhancing pesticide degradation. The study was necessitated by the fact that water bodies act as reservoirs of what remains after plants and soil accumulate the said pesticides and their breakdown products. The broad objective was to have zeolite as a cheaper and reusable drinking water cleaning agent capable of enhancing pesticide degradation during water treatment. The activities of the project included; purchase and dehydration of the zeolites, exposing various concentrations of pesticides in water containing known concentrations of zeolites. Sample water used was taken from Kisumu City at the shore of Lake Victoria. Chemical analysis of residues of pesticides was done by GCECD and GC-MS. Various experimental set ups were made to enable the study of the three aspects mentioned above and ANOV As (students'« test) was used to show variations In this study, activated Faujasite -X and -Y Zeolites were separately exposed to different concentrations of I, 1 - (2, 2, 2 - dichloroethyldiene) bis( 4 - chlorobenzene) (Dichloro dipheny trichloroethane - DOT) water solutions. For the DOT solutions of <\ 0 ppm, the resultant degradation products and residual DOT were minimal. Those of> 10 ppm, the Faujasite-X and -Y media showed an initial DOT degradation halflife of approximately 6.1 hours and 9.6 hours respectively. The main degradation product in the Faujasite - X was Dichloro diphenyl dichloroethylene (DOE) whereas in the Faujasite - Y, considerable amounts of both DOE and Dichloro diphenyl dichloroethane (ODD) were obtained. The information obtained furthered scientific knowledge on effectiveness of zeolite to enhance pesticide residue degradation in water. The information can be used by various environmental authorities and municipal water treatment bodies to enhance the quality of drinking water.