Adsorptive elimination of methylene blue dye from aquatic system using biochar produced from cocoa shell

The present research aims to investigate the potential of new biochar prepared from cocoa shell (CS), through the chemical modification method [sulfuric acid-modified CS (SMCS)]. The prepared material was found to possess an excellent adsorption capacity for the elimination of Methylene blue (MB) dye from a polluted environment by experimenting the several operating parameters which include initial dye concentration, contact time, solution pH, temperature and adsorbent dose. SMCS was characterized using scanning electron microscopy-energy dispersive analysis of X-rays, thermo-gravimetric analysis, Fourier transform infrared, and Brunauer-Emmett-Teller analysis. The equilibrium data were best discussed by the Freundlich model. Langmuir model capacity was estimated at 163.5 mg/g for MB dye removal. The feasibility and spontaneous activities of the adsorption process were observed because of the negative values of Gibbs free energy obtained for SMCS-MB dye adsorption system. Pseudo-first-order, pseudo-second-order, and Elovich kinetic models have been tested for kinetic data of SMCS-MB dye system. Pseudo-firstorder model showed good results for SMCS-MB dye system. Through obtained results, it was concluded that the SMCS can act as a potential low cost, environmental friendly, and effective adsorbents and which can be employed as an alternative to various commercial adsorbents.