Application of Different Isotherm Models on Lead Ions Sorption onto Electric Furnace Slag

The effect of temperature on the equilibrium sorption of Pb 2+ from aqueous solution onto a low-cost electric furnace slag was investigated. In this paper, two-parameter isotherm models namely the Langmuir and the Freundlich and three-parameter isotherm model namely Redlich–Peterson were applied to describe the isotherms and to calculate their constants. The best estimation of the parameters of these models by a non-linear regression analysis was obtained. A comparison between two-parameter and three-parameter isotherms was reported. The characteristic parameters for each isotherms and related coefficient of determination (R) have been determined using MATLAB 6.5. All the coefficients of determination (R) of the non-linear method are close to unity. The Redlich−Peterson isotherm produced a higher coefficient of determination values in comparison to all the isotherms studied.