Removal of Heavy Metals from Waste Water by Adsorption

Abstract

Since last decades awareness towards heavy metal removal from wastewater has been increased due to enormous health problem is being created by the heavy metal concentrated water. Regulatory authority is stricter for reduction of industrial waste. In the conventional method the chemical precipitation is most useful method. In this study physico-chemical adsorption was used. The natural adsorbent like bentonite,zeolite,kaolinite,montrmonillite to replace costly and harmful chemicals. The adsorption of Pb(II), Zn(II), Fe(II) onto bentonite,zeolite, kaolinite and montrmonolite was examined in aqueous solution with respect to the pH, adsorbent dosage, contact time, and temperature. The linear Langmuir and Freundlich and Dubinin-Rudukshek (D-R) models were applied to describe equilibrium isotherms. The adsorption capacity for Pb(II), Zn(II), Fe(II) were found from bentonite, zeolite, kaolinite. and montmonillite respectively. Bentonite , kaonite montrmonillite and zeolite may be carried out via chemical ion-exchange mechanism.. These parameters showed that the adsorption of Pb (II), ,Zn(II) andFe(II). onto kaolinite ,zeolite, bentonite, montrmonillite, was feasible, spontaneous and exothermic process in nature. Furthermore, the natrajan kalhaf first order reaction, pseudo-second-order were used to describe the kinetic data. The experimental data fitted well the pseudo-second-order kinetics.