Maryam Sourani - Faculty of Science, Department of Chemistry University of Arak, Arak, Iran

In this paper, acacia trees and ash plant have been used as absorbents for the removal of metal ions of lead and cadmium from aqueous in continuous systems. The effects of some factors such as PH and particle size have been studied. PH 5 is optimal for absorption. Thomas model and Yoon and Nelson model are used for comparison with experimental data of break curve. For all adsorbents, both models showed good agreement with the experimental data. The optimum conditions for both the absorbers and for both metals the PH 5, particle size is 0/1 to 30/0 mm. In the optimum conditions for maximum adsorption capacity of acacia and ash respectively is 26/36 and 65/50 mg/g for lead. Similarly, cadmium uptake capacity of the ash in the optimal conditions is 74/18 mg/grams. Lead removal efficiency for locust and ash respectively is 25/46 and 25/50%. Cadmium removal efficiency for Ash is 66/47 %. The results of absorbs with fixed platform show that with increasing the adsorbent weight and PH solution , break time and saturation time increases and with increasing adsorbent particle size, flow rate and initial concentration of the solution, these times are reduced. Both Thomas and Yoon and Nelson model showed good agreement with experimental data, and the correlation coefficient in all phases of the experiment was respectively.