Abstract
This study explores the kinetic and equilibrium performance of eggshell as an adsorbent for hexavalent chromium and cadmium ion removal from wastewater. The experimental removal of the two metal ions was performed batch-wise and the influence of variables like initial metal loading, pH, contact time, and adsorbent dose. Fourier-transform infrared spectroscopy spectra reveals that chromium and cadmium ion interact with carbonyl, carboxylic, hydroxyl functional groups in eggshell. The best pH is 6, and the adsorption capacity improves with increasing initial concentration of adsorbate, pH, contact time and adsorbent dosage for chromium and cadmium ion. Pseudo-second-order kinetics is the most suitable model for the removal of chromium and cadmium ion, while the equilibrium agrees with Freundlich isotherms. These outcomes reveal that eggshell is a promising cheap adsorbent for adsorption of toxic heavy metals like chromium and cadmium ion from aqueous solution.