Liquid Phase Adsorption of Ni, Cd and Pb on Zeolite as Affected by Zeolite size and Concentration of Solution

Zeolite is widely used for removing heavy metals from aqueous solutions. The objective of this study was to assess three sizes of zeolite in removing lead، nickel and cadmium from wastewater. A splite-plot experimental design was employed with 45 treatments and three replications at Shiraz University Lab in 2011. The treatments were five different concentrations of the pollutant and three sizes of zeolite (0. 075، 0. 2 and 0. 425mm). The concentrations for lead were: 40، 250، 500، 1000 and 1250 mg/l and 4، 6، 15، 20 and 40 mg/l for nickel and cadmium. The results showed that the effect of concentrations of pollutant was significant، and by increasing the concentration of pollutant، absorption of heavy metals by zeolite increases linearly. Maximum lead absorption occurred at 1250 mg/l with 59. 97 mg and minimum absorption of lead was related to the concentration of40 mg/l with 1. 82 mg for 1 grams of zeolite. Maximum and minimum nickel absorptions were related to the concentration of 40 and 4 mg/l with 1. 92 and 0. 16 mg for 1 grams of zeolite، respectively. The values were 1. 87 and 0. 18 mg for 40 and 4 mg/l for cadmium، respectively. The effect of size of zeolite on the pollutant adsorption was not significant.