Biosorptive removal of lead and cadmium ions from aqueous solution: The use of carrot residues as low cost non-conventional adsorbent

Abstract

Objectives: Carrot residue as low cost, non-conventional adsorbent was used for biosorptive removal of lead and cadmium from the aqueous solution. Methods: A batch adsorption method was experimented for biosorptive removal of lead and cadmium ions from the aqueous solution. Findings: Experimental data fitted well to both Langmuir and Freundlich isotherm models. The calculated q max for lead and cadmium was 0.522 mg/g and 0.421 mg/g respectively. Thermodynamic parameters like ΔG, ΔH and ΔS showed spontaneity endothermic nature of adsorption for cadmium ion and exothermic nature for the lead ions. Nearly 93% removal of lead and 92% removal of cadmium were observed in about 35 minutes at pH @ 3 and 5 respectively, under the batch test conditions. Conclusion: Carrot residue was investigated as low cost non-conventional adsorbent for the sorption of cadmium and lead ions from the contaminated water under various experimental conditions like pH, dosage amount and contact time.