Investigation of the removal of some high polarity pesticides from aqueous solutions by adsorption and electrosorption onto activated carbon cloth with spectrophotometric method

The aim of this thesis is to investigate the removal of high polarity pesticides, which are being used intensively for agricultural purposes, such as paraquat, diquat, difenzoquat, glyphosate, glufosinate, bialafos and aminomethylphosphonic acid, from their aqueous solutions onto high area activated carbon cloth. The concentration changes of pesticides in aqueous solutions during adsorption and electrosorption were monitored by UV-VIS spectrophotometric method. This method was applied in-situ for paraquat, diquat and difenzoquat, and ex-situ for glyphosate, glufosinate, bialaphos and aminomethylphosphonic acid. The kinetic data obtained from adsorption and electrosorption studies were treated according to two most widely used kinetic models; pseudo first order and pseudo second order. The pseudo second order kinetic model was found to represent the experimental data better than the pseudo first order model for both adsorption and electrosorption. The adsorption isotherm data were fitted to Langmuir and Freundlich isotherm equations. Freundlich isotherm model was found to represent experimental data better than Langmuir model. Reasonable removal efficiencies reached by open-circuit adsorption was improved with the application of electrosorption. Some regeneration studies for activated carbon cloth loaded by pesticides were also carried out by electrodesorption.