The Beneficial Effect of Chitosan - Biochar Blend on the Biosorptive Removal of Heavy Metal Copper from Aqueous Solution

The present study investigates the efficacy of a biochar-chitosan blend in biosorptive elimination of copper from an water. Biochar was prepared from corncob waste by pyrolysis at 600°C under a nitrogen atmosphere and blended with a chitosan solution. The prepared chitosan-biochar (CS-BC) blend was characterized using FTIR, XRD, BET, and SEM analyses. Adsorption tests in batches were carried out to evaluate the adsorption capacity of the CS-BC blend for Cu(II) ions, considering several variables, including pH, starting metal concentration, contact time, and adsorbent dose. The optimal pH for Cu(II) adsorption was found to be 5, having the highest sorption of 313.97mg/g. The adsorption capacity increased with increasing adsorbent dosage up to 4 grams and contact time up to 480 minutes. Adsorption isotherm studies revealed that the adsorption process was best explained by the Freundlich model indicating multilayer sorption. According to kinetic analyses, the pseudo-second-order adsorption process was followed. Desorption studies using 0.1M HCl demonstrated a high regeneration capacity of the CS-BC blend, with up to 99% recovery of Cu(II) ions. The results suggest that the chitosan-biochar blend is an effective and economically viable adsorbent for extracting copper, a heavy metal, from water-based solutions.