Preliminary Study on the Use of Urea Activated Melon (Citrullus colocynthis) Husk in the Adsorption of Cadmium from Waste Water

Abstract

Adsorption studies were carried out using urea activated melon (Citrullus colocynthis) husks as a low-cost potential adsorbent to remove cadmium from industrial effluents. Bioabsorption parameters considered were as contact time, adsorbent dosage and adsorbate concentration. Cadmium removal was found to be dependent on the three parameters with maximum removal attained at 50 minutes with 0.8 and 1.0g of urea activated melon husk. Cadmium ions were mostly removed at low adsorbate concentration. Maximum removal was attained at 20 minutes with 97.6% adsorption. Adsorption isotherms had positive correlation with both Langmuir and Freundlich isotherm models and their r² values ranged from 0.911 – 1.00. Experimental data were also evaluated to find out kinetic characteristics of the adsorption process. Adsorption process for the heavy metal ion was found to follow pseudo-second order adsorption kinetics with the r² value of 0.8309. Activated melon husk, a readily available adsorbent was found to be efficient in the uptake of Cd (II) ions in industrial effluents, thus, confirming it as an excellent alternative for the removal of heavy metals from water and waste water.

Keywords: Bioadsorption, Cadmium removal, Waste water, Melon husk