A COMPARATIVE STUDY ON THE BIOADSORPTION OF CADMIUM AND LEAD FROM INDUSTRIAL WASTE WATER USING ACTIVATED MELON (Citrullus colocynthis) HUSK

Abstract

Melon (Citrullus colocynthis) husk (Lloyd,1898), a readily available agricultural waste product was used as a low-cost potential adsorbent to remove cadmium and Lead from industrial effluents. Adsorption studies were carried out on three different activated melon husks as a function of parameters such 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 min with 0.8 and 1.0g for urea and sodium hydroxide (NaOH) activated melon husks and at 70min with 0.6g for sulphuric acid (H2SO4) activated melon husk. Both metals were mostly removed at low adsorbate concentration. Lead removal did not show strict dependency on these parameters with maximum removal attained within the first minute for both NaOH and H2SO4 activated melon husks with records of 100% adsorption. Maximum removal was attained at 20min by urea activated melon husk with 97.6% adsorption. The pairwise t- test showed that lead is better adsorbed than cadmium. The t-test also indicated that H2SO4 activated melon husk was the most efficient absorbent followed by NaOH and then urea activated melon husk. Activated melon husk, a readily available adsorbent was found to be efficient in the uptake of Cd (II) and Pb (IV) ions in industrial effluents, thus, predisposing it as an excellent alternative for the removal of heavy metals from water and waste water.