The Process and Kinetics of Pesticide Desorption from Clay as a Function of Cleaning Polluted Waters

Abstract

This study presents an investigation into the desorption process of pesticides, namely benalaxyl, atrazine, dimethoate, and methomyl, from aqueous solutions in natural Brari clay (Tirana) located at 41°21′14.49″ N and 19° 50′17.74″ E and Dardha clay (Korça) located at 40°31′16.59″ N and 20°49′33.69″ E. The desorption process was fast, where in the first 2 hours of contact, 99.1% of atrazine was desorbed from Brari clay, and 90.1% of atrazine was desorbed from Dardha clay. In addition, in the first 2 hours of contact, 80.3% of benalaxyl was desorbed from pear clay and 79.2% of benalaxyl from Brari clay; 96.2% of methomyl and 81.2% of dimethoate were desorbed. According to the acquired curves, the desorption process began with the dominance of methomyl from Brari clay, followed by dimethoate from Brari clay, dimethoate from Dardha clay, atrazine from Brari clay, benalaxyl from Brari clay, benalaxyl from Dardha clay, and lastly atrazine from Dardha clay. Hence, compared to Dardha clay, less pesticide underwent desorption with Brari clay. Researchers immediately wondered how long (time) these pesticides would remain in the corresponding clays following the adsorption process, so the study of the kinetics of the desorption of pesticides from clay is of special interest. The kinetics of the pesticides atrazine, benalaxyl, dimethoate, and methomyl (all at a concentration of 25 mg/L) desorbing from natural Brari and Dardha clays are presented here.