Lignin-chitosan blend for methylene blue removal: Adsorption modeling

In this work, a comprehensive comparative analysis of various approaches for the modeling of the adsorption process was carried out to understand the adsorption isotherm and kinetics. The evaluated isotherm models included Langmuir, Freundlich, Dubinin-Radushkevich, Tempkin, Flory-Huggins, Hill, Redlich-Peterson, Sips, Toth, Koble-Corrigan, Khan, Radke-Prausnitz, Brunauer-Emmett-Teller, Frenkel-Halsey-Hill, MacMillan-Teller, Harkins-Jura, Halsey, Henderson, Fritz-Schluender, Vieth-Sladek, Valenzuela-Myers, Jovanovic, Baudu and Elovich. The evaluated kinetic models included pseudo-first-order, pseudo-second-order, Avrami, Adsorption kinetic and Bangham. For a detailed comparison, the experimentally measured adsorption data of methylene blue from water effluent on a lignin and chitosan blend were used. It was demonstrated that current kinetic models and isotherms provide some correlative method and view to the adsorption data that are useless without prior experimental data. It was revealed that the best results were obtained for Langmuir-1 farm isotherm and the worst one was obtained for Harkins-Jura isotherm. In terms of kinetics, the linearized Form 2 of the pseudo second-order indicated better goodness of fit to the experimental kinetic data. (C) 2018 Elsevier B.V. All rights reserved.