Lead removal from wastewater using fluted pumpkin seed shell activated carbon: adsorption modeling and kinetics

ABSTRACT

Activated carbon produced from fluted pumpkin [Telfairia occidentalis] seed shell was utilized for the removal of lead [II] ion from simulated wastewater. Adsorption tests were carried out in series of batch adsorption experiments. Several kinetic models [Bhattacharya-Venkobacher, Elovich, pseudo first and second order, intra-particle and film diffusion] were tasted for conformity to the experimental data obtained. The Langmuir and Freundlich adsorption models were also used to test the data. The amount of lead [II] ion adsorbed at equilibrium from a 200 mg/L solute concentration was 14.286 mg/g. The experimental data conform very well to the pseudo-second order equation where equilibrium adsorption capacities increased with increasing initial lead [II] concentration. The rate of the adsorption process was controlled by the film [boundary layer] diffusion as the film diffusion co-efficient values obtained from data analysis were of the order of 10 6 cm[2]/s. From the plots, the linear regression coefficient [R2] of the Langmuir model was higher than that of the Freundlich the adsorption isotherm obeyed the Langmuir model better than the Freundlich model