Kinetic and equilibrium studies of methylene blue adsorption on functionalized polymethyl methacrylate in polyvinylidene fluoride–hexafluoropolypropylene matrix

Abstract

Herein a novel polymeric adsorbent composite material was introduced for the adsorption of methylene blue from aqueous solutions for the purpose of water treatment. Adsorption process was examined by using Langmuir and Freundlich isotherm models together with pseudo-first and second order kinetic analysis. It was found that characteristic of the adsorption process was well described by Langmuir isotherm following pseudo-first order kinetic route. The maximum monolayer adsorption capacity was determined as 49.04 mg g−1. In light of thermodynamic parameters of the adsorption and removal of MB from the composite in acidic solution suggested that the process was based on ion-exchange mechanism. Negative values of Gibbs free energies changing from − 5.41 to − 15.99 kJ mol−1 with increasing temperature demonstrated that adsorption process occurs spontaneously. Heat of adsorption and entropy values were found as 58.30 kJ mol−1 and 0.23 kJ mol K−1, respectively. Therefore, adsorption process was endothermic in nature without noticeable disorder. The material consisting of functionalized poly(methyl methactrylate) in the polyvinylidene fluoride–hexafluoropolypropylene matrix is considered to be a potential adsorbent material for the treatment of polluted waters.