Chloroorganic pesticide adsorption from water solution using sewage sludge vermicompost as a natural sorbent

Abstract

Dozens of thousands of tons of pesticide waste have been stored since 1950s. The corrosion of concrete bunkers and wells where the expired pesticides are deposited causes the risk of toxic leakage due to deteriorating conditions of these constructions. Such hazardous spill might be transported by underground waters in the form of so-called underground inflow and subsequently might reach a network of surface waters. Evaluating the adsorption potential of natural sorbent for pesticide was the main goal of this research. The adsorption balance was examined in order to analyze the influence of the adsorption mechanism of HCH molecules on vermicompost. The adsorption of HCH isotherms by vermicompost at constant temperature was tested experimentally. The Freundlich, Langmuir and BET's adsorption isotherm models describe the experimental data within the acceptable error ranges. The Freundlich model proved to be more suitable for the experimental data. The form of isotherms indicates that HCH is adsorbed as a monolayer; therefore no obstacles occur in order for water and pesticide molecules to cover the adsorption surface.