Kinetics of and solvent effects on photodegradation of hexachlorobenzene (HCB) and endosulfan (endosulfan I and endosulfan II) in solution

Abstract

Organochlorine pesticides are chlorinated hydrocarbon compounds. The production and use of organochlorine pesticides have been restricted around the world because they are persistent and toxic and able to undergo long-range transport and bioaccumulate. It is necessary to develop efficient techniques for eliminating organochlorine pesticides from environmental media, and we also need to better understand how these techniques operate. Understanding how organochlorine herbicides behave in various environmental settings is very crucial. We looked on the photodegradation of endosulfan (endosulfan I and II) and hexachlorobenzene (HCB), two common organochlorine insecticides. Tests were conducted with pesticides at different concentrations, dissolved in various organic solvents, and exposed to light at different wavelengths. Density Functional Theory (DFT) was employed to study solvent effects. Degradation kinetics followed first-order models. The pesticides dissolved in various organic solvents showed a decrease in their degradation rates in the following order: toluene > acetone > n-hexane. It was discovered that there was a good chance the Cl atoms on the benzene ring in HCB would be eliminated through nucleophilic processes. It was discovered that endosulfan breaks preferentially at the SO double bond. The findings will aid in the development of strategies for successfully eliminating organochlorine pesticides from environmental media by aiding in the prediction and assessment of the photochemical behaviors of the pesticides under various environmental circumstances.

Keywords

• Organochlorine pesticides
• Degradation characteristics
• Density functional calculation
• Solvent effect