Adsorption of Heavy Metals (Lead Ion) From Industrial Waste Water Using Acidified Bentonite Clay

Abstract

The adsorption potential of acidified bentonite clay obtained from Adamawa state; a location in North Eastern Nigeria was investigated through batch experiments conducted to remove Pb2+ from an aqueous solution. A constant weight of 0.5g of acidified bentonite clay was used throughout the experiment. Pb2+ adsorption was found to be dependent on initial concentration, contact time, temperature and pH. An initial metal ion concentration of 50ppm and 10ppm gave maximum uptake (99%) and minimum uptake (87%) respectively. Temperatures of 70 o C and 50 o C altered the adsorption; giving (99.75%) and (96.2%) as maximum and minimum uptakes respectively. A 99.93% adsorption was recorded as maximum at contact time of 10.0 min while 95.79% was the minimum at 40.0 min. At pH level of 6.0, adsorption was maximum (98.8%) and minimum (89.8%) when pH was reduced to 4.0. Experimental isotherm data were analyzed using the Langmuir, and Freundlich equations. The kinetic processes of Pb2+ adsorption on the bentonite clay were described by applying pseudo-first order and pseudo-second order rate equations. The kinetic data for the adsorption process obeyed pseudo-second order rate equations. R2 was used to enhance the justification analysis for each used model (1st order: R2 = 0.423, 2nd order: R2 =1, intra particle diffusion model: R2 =0.997). The acidified bentonite clay investigated in this study exhibited a high potential for the removal of Pb2+ from aqueous solution.