Kinetic and equilibrium modeling of single and binary adsorption of methyl tert-butyl ether (MTBE) and tert-butyl alcohol (TBA) onto nano-perfluorooctyl alumina

Abstract

Wide spread use of methyl tert-butyl ether (MTBE) has led to pollution of drinking water sources and has received great attention. In this study, single-component and binary competitive adsorptions of MTBE and tert-butyl alcohol (TBA) onto two novel adsorbents, i.e., nano-perfluorooctyl alumina prepared by using nano-γ-alumina (nano-PFOALG) and nano-boehemite (nano-PFOALB) as the supports were investigated. In single-component experiments, experimental data were modeled with five isotherm equations (Langmuir, Freundlich, modified BET for liquid phase, Sips and Dubinin–Radushkevich). Results revealed that the adsorption isotherms of both components on two adsorbents were best described by the modified BET isotherm. The multicomponent data were fitted to seven different predictive models, especially an extended form of modified BET, has been used in the present work. For the binary adsorption system, it is found that the quality of respective single-component isotherms for each component has significant effect onto the predicting multicomponent adsorption via Ideal Adsorbed Solution Theory (IAST). Accordingly, IAST-BET provided an accurate description of MTBE/TBA binary adsorption experimental data, hence being a reliable isotherm for the design of industrial adsorption equipment for wastewater treatment especially in high concentration ranges. The kinetic study was also conducted and two common kinetic models (pseudo first-order and pseudo second-order) were used to determine kinetics parameters. The mechanism of the adsorption process was described from the intraparticle diffusion model. The kinetic data showed a closer fitness to the pseudo-second order model. Maximum values for the rate constant, k2, were obtained for MTBE and TBA adsorption, as 0.252 and 1.494 (gmg−1min−1), respectively.