Mesoporous magnesia sorbent for removal of organic contaminant methyl tert -butyl ether (MTBE) from water

Abstract

ABSTRACT Methyl tertiary butyl ether (MTBE) is used as a gasoline additive formed by the reaction of isobutylene and methanol. Due to its high water solubility and low soil adsorption coefficient, leakages from storage facilities cause immediate groundwater contamination. The aim is to use alternative adsorbent for the removal of MTBE that causes various environmental and health problems. Mesoporous magnesia (MgO) that was synthesized via template-free hydrothermal method and commercial adsorbent Sepabeads-207 (SP-207) were used in this study. MTBE adsorption experiments were carried out at room temperature with a fixed sorbent/liquid ratio (0.1 g sorbent/10 mL aqueous solution) and 100–500 mg/L MTBE initial concentrations. Batch adsorption experiments showed that MgO and SP-207 have high MTBE adsorption capacity with a maximum adsorption amount of 333 and 233 mg MTBE/g adsorbent. Langmuir, Freundlich, Temkin, and Dubinin–Radushkevich models of adsorption isotherms were used to investigate the adsorption behavior and the Langmuir isotherm model showed a better fit. Adsorption kinetic studies were also performed, and the pseudo-second-order kinetics fitted well with experimental data. Gibbs free energy changes of adsorption were obtained as −48.4 and −60.3 kJ/mol for MgO and SP-207, respectively. Methanol was used to regenerate the used adsorbents, and the re-use of MgO demonstrated good performance.