Equilibrium and Kinetic Study of the Removal of Cadmium from the Human Blood Plasma Using Dried Allium cepa Biomass

Abstract

The therapeutic importance of Allium cepa has been reported in previous studies. However, little has being known of its efficiency to remove heavy metal from the human blood plasma. Thus this study seeks to investigate the efficiency of Allium cepa biomass in detoxification of Cadmium ions from aqueous solution of human blood plasma in-vitro. The biosorbent was prepared and identified using FTIR which revealed the presence of carbonyl group, amide group, sulphoxide group, ether and aromatic groups. The optimum sorption was investigated and the experimental data revealed an equilibrium pH 4, optimum Cd2+ concentration 70 mgL-1 and optimum biosorbent dose 0.80 g were obtained and used to study the equilibrium sorption rate which occurred at 80 mins with 99.98% removal at ambient temperature. The experimental data fitted Pseudo Second order kinetic as indicated by the correlation coefficient value (R2)=0.9961 with a rate constant K2=0.3730 g.mg-1.min-1. The experimental data conforms to Freundlich isotherm and Jovanovis isotherm, however Freundlich isotherm showed best fit with correlation coefficient (R2)=0.632, sorption capacity (KF)=3.3113 and sorption intensive (n)=1.870. The separation factor of the Langmuir isotherm (RL)=0.0141, which suggests that the overall adsorption process was favourable.