A practical and theoretical study of the pesticide thiamethoxam on activated charcoal derived from Iraqi date seeds and Koura clay as good absorbents

Abstract

In this study, activated charcoal extracted from Iraqi date seeds was used to study the effective removal of liquid thiamethoxam pesticide residues. Using Karwa clay to increase the adsorption capacity of thiamethoxam, activated charcoal made from Iraqi date kernel waste was produced using two different processes: chemical catalysis and physical catalysis treated with a phosphoric acid solution (5M). Several elements, including thiamethoxam concentration, mixing duration, contact time, amount of activated charcoal temperature, and pH of the medium, have been studied to influence thiamethoxam removal efficiency. The results showed that the maximum adsorption dose was 0.05 g/L, the dye concentration was 100 mg/L, and the adsorption duration for activated charcoal was 2.5 hours, which is the ideal condition for removal efficiency of 10-63%, while the adsorption duration for activated charcoal was 2.5 hours, which is the ideal condition for removal efficiency. 10-63%. The adsorption time on the Kora clay was 3.5 hours, which is the ideal condition for removal efficiency of 10-74%. Adsorption equilibrium was performed using Freundlich, Temkin, Harkins-Jura, Dupin, Elovitch, and Langmuir, and the results on the activated charcoal surface showed that the Harkins-Jura model with R2 values of 0.987 and the results on the kura clay surface showed that the Langmuir model with R2 values of 0.157 showed agreement. Best with experimental data for adsorption. According to thermodynamic analysis, the pesticide is endothermic, spontaneous, and indicates increased unpredictability at the adsorbent interface. It also indicates the pHZpc of the negatively charged carbon surface at pH = 2.0. Two pseudo-first-order models and two pseudo-second-order models were included in the kinetic analysis. The results indicate that the pseudo-second order model with R2 > 0.9661 on the activated charcoal surface fits the experimental data best. The results also indicate that the pseudo-second order model with R2 > 1 on the Kura clay surface fits the experimental data better. Density function theory, or DFT, was used to simulate thiamethoxam and help us determine the origin of the reaction.