Adsorption of Methylene Blue From an Aqueous Solution Using a Cucurbituril Polymer

This article presents a study on the batch adsorption of methylene blue (MB) in an aqueous solution onto a cucurbituril polymer (CP) in order to explore its potential use as an adsorbent for dye removal from wastewater. Equilibrium studies showed that MB had a high affinity in a basic medium, but decreased as solution pH decreased. The adsorption of MB decreased with an increase in ionic strength for all four types of cations (Na+, K+, Mg2+, and Ca2+). The pseudo first-order, pseudo second-order kinetic model, and the intraparticle diffusion model were used to fit the kinetics process of MB adsorption on the CP. The result implies that the pseudo second-order model provided a high degree of correlation with the experimental data, and intraparticle diffusion is not the only rate-limiting step. The experimental isotherm data were analyzed using the Langmuir, Freundlich, and Redlich-Peterson isotherm model at initial pH 5.6 and 11. Five error analysis methods were used to evaluate the data. The error values indicated that the Redlich-Peterson and Langmuir models could provide the better quality of fit at initial pH 5.6, and Redlich-Peterson and Freundlich models described better the MB adsorption data at initial pH 11.0. (c) 2014 American Institute of Chemical Engineers Environ Prog, 34: 512-519, 2015