The Factors on Removal of Zinc Cation from Aqueous Solution by Bentonite

The removing zinc cation from aqueous solution by Ca-bentonite and Na-exchanged bentonite was studied. The factors such as the initial concentration of Zn, the liquid-to-solid ratio, pH, adsorption time, stirring speed, coexisting ions, temperature and bentonite particle size were investigated. The results show that the adsorption process of bentonite accorded with the Freundlich isotherm model, the removal of Zn by Ca-bentonite and Na-exchanged bentonite reached equilibrium in 2 h, and adsorption of Nabentonite was superior to Ca-bentonite. The adsorption rate of zinc increased with increasing pH, temperature, stirring speed, time span and with decreasing bentonite particle, the initial concentration of Zn and the liquid-to-solid ratio. In mixed solution which contains Pband Cr, Pb has no influence on the removal of Zn by both the bentonites while Crcan decease it.