Nonlinear Fitting of Iron Sorption on Bentonite to Theoretical Isotherm Models

Abstract

A comparative analysis of adsorption models application for the description of experimental isotherms of iron adsorption on two samples: natural bentonite and bentonite irradiated with microwave irradiation. Sorption isotherms are described using the theories of Langmuir, Freundlich, Redlich-Peterson and Langmuir-Freundlich. The constants and parameters of these equations are determined. Nonlinear fitting of experimental data to the theoretical models of isotherms showed that adsorption by native bentonite corresponds to the three-parameter Redlich-Peterson model, and microwave irradiated - to the Freindlich isotherm. This modeling allows to predict the maximum adsorption capacity, which is 37.7 mg / g of natural bentonite and 64.4 mg / g of the modified sample.