Sonochemical degradation of organophosphorus pesticide in dilute aqueous solutions

Article type: Research Article

Authors: Farooq, Robina | Lin, Feng-kai | Shaukat, S.F. | Huang, Jian-jun

Affiliations: College of Resources and Environmental Engineering, East China University of S&T, Shanghai 200237, China | Government College, Department of Physics, Lahore, Pakistan

Abstract: Ultrasonic irradiation was found to accelerate the rate of hydrolysis of omethoate in aqueous solution over the pH range of 2–12. Process parameters studied include pH, steady-state temperature, concentration, and the type of gases. Greater than 96% hydrolysis was observed in 30 minutes through this process and the rate of destruction increased with the help of more soluble and low thermal inert gas. So with Krypton, omethoate was found to undergo rapid destruction as compared with Argon. In the presence of ultrasound, the observed first-order rate of hydrolysis of omethoate is found to be independent of pH. The formation of transient supercritical water (SCW) appears to be an important factor in the acceleration of chemical reactions in the presence of ultrasound. A detailed chemical reaction mechanism for omethoate destruction in water was formulated. Experimental results and theoretical kinetic mechanism demonstrated that the most of the omethoate undergo destruction inside the cavitating holes. A very less effect of temperature on the degradation of omethoate within a temperature range of 20–70°C proves that a small quantity of omethoate undergoes secondary destruction in the bulk liquid.

Keywords: sonochemical degradation, omethoate pesticide, sonolysis, inert gases

Journal: Journal of Environmental Sciences, vol. 15, no. 5, pp. 710-714, 2003