Biosorption of Copper and Lead from Human Blood Plasma Using allium cepa

Lead and Copper are inorganic pollutants that are non-biodegradable. When released into the environment, they have adverse effect on human beings and animals when ingested. Allium cepa (Onion) is a vegetable product largely consumed for its potential therapeutic importance. This study investigates the efficacy of Allium cepa in removal of Cu2+ and Pb2+ from human blood plasma in-vitro. The adsorption rate was studied at optimum values of pH 6 for Cu2+, and pH 4 for Pb2+, metal ion concentration (50mgL-1), and Allium cepa dose 0.60g for Cu2+ and 0.40g for Pb2+ at physiological temperature (38°C). SEM analysis revealed physical disintegration in the surface morphology of Allium cepa biomass after adsorption. Equilibrium sorption occurred at80 mins with 99.316% removal for Cu2+ and 90minswith 99.8914% removal for Pb2+. The adsorption data obtained for Cu2+ best fits Temkin isotherm with correlation value (R2)=0.901 with low binding energy (AT)=1.340 Lg-1 while the adsorption data for Pb2+ best fits Freundlich isotherm with correlation values (R2)=0.965 at Freundlich coefficient (kf)=3.169.27 Lmg-1. The result also revealedthat physiosorption and chemosorption occurred between the metal ions and binding site on the Allium cepa biomass as Intraparticle diffusion proved not to be the only rate controlling step.