Comparative Studies of Adsorption of Heavy Metals from Wastewater by Blighia Sapida Seeds, Pods and Their Blends

Abstract

This study was carried out to compare the adsorption capacities of modified activated carbons prepared from Blighia sapida seed, pod and their blends in ratio blend (1:1), blend (1:3) and blend (3:1) for the removal of heavy metals (Pb, Cu, Zn & Fe) from wastewater. The adsorption studies of heavy metals from wastewater revealed lead (Pb) to be below detectable limit, while Cu (2.14 mg/L), Fe (1.80 mg/L) and Zn (2.82 mg/L) were estimated to be above WHO limits. Batch adsorption experiments were investigated by varying contact time, pH, dosage and temperature. The optimum contact time required for adsorption was 40 minutes for Cu, Zn and Fe. Adsorption data were fitted in to pseudo-first-order and pseudo-second-order kinetics model and the experimental values were fitted well for pseudo-second-order kinetics due to correlation coefficient, R2 values (≥ 0.9) which showed adsorption rate of Fe greater than Cu and Zn. Thermodynamic studies shows the positive value of ∆G° which is non-spontaneous for the adsorption of zinc onto the blend (1:1). This study showed that activated carbon from Blighia sapida could be used as low cost effective adsorbents in the treatment of industrial effluent