Optimization and Kinetics of Bioadsorption of Aqueous Potassium Permanganate in Charred Cacao Shells

Abstract

In this study, charred cacao shells were tested for their capability as bioadsorbent for aqueous potassium permanganate. Optimization of adsorption parameters showed that the best amount of adsorbent is 0.5% w of cacao biochar/v of 0.005 N aqueous KMnO4 with a removal efficiency of 98.79%, and the optimum particle size is 212 mm, with a corresponding removal efficiency of 99.76%. Kinetics studies showed that the adsorption fits a pseudo-first order reaction with R2 = 0.9833. Lastly, the adsorption data fits the Elovich isotherm with R2 = 0.9712, which strongly suggests a multi-layer chemisorption on a heterogenous surface. Conclusively, the charred cacao shells were found to be effective as an adsorbent of aqueous potassium permanganate. Furthermore, the resulting product of adsorption can be used to study adsorption of other substances due to its multi-layer nature.