Adsorption Isotherm Parameter Estimation

Determination of the parameter values for the Langmuir and Freundlich adsorption isotherm equations for water and wastewater treatment samples often requires estimation of the concentration of nonadsorbable material. Present techniques for estimating the concentration of that material can introduce bias into the data. Furthermore, linearization of the isotherm equations usually leads to application of least-square analysis to variables other than the true dependent and independent variables. A nonlinear programming technique is presented which allows simultaneous evaluation of the concentration of nonadsorbable material and the isotherm parameters. The technique is based upon the flexible polyhedron concept and achieves minimiation of the sum of squares error term associated with the solute concentration when expressed as a function of the adsorbent concentration.