Abstract

Cadmium can be found in wastewater in high concentrations and can cause dangerous effect on aqueous environment and human health. At present, many methods have been used to heavy metals removal. Among this clean up techniques, adsorption techniques by using low-cost adsorbent are more considerable. In this study, batch adsorption experiments were conducted for removal of cadmium ions from aqueous solutions by using saxaul tree ash as a low-cost adsorbent. The batch experiments were conducted in various conditions as follows: pH (3 to 11), adsorbent dose (0.5 to 6 g/L) g, contact time (15 to 210 min), and initial cadmium concentration (5-50 mg/L). Based on the results, pH= 5 with an adsorbent dose of 4 g/L with a 75 min contact time were found to be the optimum for adsorption of cadmium on saxaul tree ash. Also, the results showed that adsorption efficiency is decreased with increase in initial concentrations of cadmium. The isotherm experiments showed that Freundlich model satisfactorily represents the proportional fitting. Therefore, base on the results of this study, saxaul tree ash can be used for efficient removal of cadmium ions from aqueous solution.