Cadmium Removal Using Egg and Peanut Shell

This work studies the adsorption efficiency of a biochar composite derived from egg and peanut shells for the removal of cadmium (Cd) from synthetic wastewater. The biochar is prepared by combining equal proportions of egg and peanut shells. The removal capacity of Cd(II) ions from aqueous solutions has been evaluated using a batch adsorption test, and a UV-VIS spectrophotometer to determine the equilibrium concentration. Results demonstrate a maximum adsorption capacity of 3.013 mg/g under conditions of 5 g/L adsorbent dosage, an initial Cd(II) concentration of 5.0 mg/L, and a contact time of 180 minutes. Isotherm modeling indicates that the adsorption process is best fitted by the Freundlich model (R² = 0.9800), implying multilayer adsorption on a heterogeneous surface. The high density of functional groups in the biochar made it more convenient for Cd(II) to attach through surface complexation and electrostatic interactions. These data imply that egg and peanut shell-derived biochar is a promising, sustainable, and effective adsorbent for the removal of cadmium contaminated aqueous environments.