An Evaluation of the Adsorptive Behaviour of Activated Carbon Derived from Hyphaene Thebaica Nut Shells for the Removal of Dichlorvos from Wastewater

Abstract

This work evaluates the adsorptive behaviour of activated carbon from Hyphaene thebaica nut shells treated with KOH for the treatment of water contaminated with Dichlorvos. The derived adsorbent was characterized by FTIR in order to study the surface chemistry. The batch adsorption technique was employed for the studies. Conditions for adsorption of the pesticides such as adsorbent dose, contact time, initial concentration, pH and temperature on adsorption of both pesticides onto the prepared adsorbent were optimized. The experimental data were also modeled by the Langmuir, Freundlich and Temkin adsorption isotherms. The result shows that adsorption of Dichlorvos increases with increased adsorbent dose, initial concentration, time and temperature. Optimum adsorption was observed at adsorbent dose of 50 mg, initial concentration of 250 ppm, temperature of 60 ⁰C .  and at contact time of 30 minutes. Optimum adsorption pH for Dichlorvos was found to be 2 respectively. The Langmuir isotherm model showed a better correlation (R² = 0.7455) compared to Freundlich and Temkin isotherm model to fit the equilibrium data. However, the experimental data values for Langmuir were inconsistent with the adsorption process as they indicated negative values. The Pseudo second order adsorption model was more suitable to describe the adsorption kinetics of the pesticide on the adsorbent. Thus, activated carbon from KOH treated Hyphaene thebaica nut shells could therefore be used effectively for the removal of Dichlorvos from waste water.