Removal of methylene blue from aqueous solution using cocoa (Theobroma cacao) nib-based activated carbon treated with hydrochloric acid

Chemical activation process was applied to prepare a cocoa nib-based activated carbon using potassium carbonate (K2CO3). The performance of the activated carbon in removing Methylene Blue from aqueous solution was investigated by batch adsorption studies. The adsorptive properties were studied in terms of initial concentration (C-0: 100-300 mg/L) and contact time effects. The experimental isotherm data fitted well the Langmuir and Temkin models. The adsorption kinetic followed the pseudo-second-order model and Boyd model explained the mechanism of adsorption. The results indicate that the chemically produced activated cocoa nib carbon has significant potential to be used as an adsorbent material for adsorption of Methylene Blue from aqueous solution.