Kinetic and equilibrium modelling of MTBE (methyl tert-butyl ether) adsorption on ZSM-5 zeolite: Batch and column studies.

The intensive use of methyl tert-butyl ether (MTBE) as a gasoline additive has resulted in serious environmental problems due to its high solubility, volatility and recalcitrance. The feasibility of permeable reactive barriers (PRBs) with ZSM-5 type zeolite as a reactive medium was explored for MTBE contaminated groundwater remediation. Batch adsorption studies showed that the MTBE adsorption onto ZSM-5 follows the Langmuir model and obeys the pseudo-second-order model with an adsorption capacity of 53.55 mg g. The adsorption process reached equilibrium within 24 h, and MTBE was barely desorbed with initial MTBE concentration of 300 mg L. The mass transfer process is found to be primarily controlled by pore diffusion for MTBE concentrations from 100 to 600 mg L. pH has little effect on the maximum adsorption capacity in the pH range of 2-10, while the presence of nickel reduces the capacity with Ni concentrations of 2.5-25 mg L. In fixed-bed column tests, the Dose-Response model fits the breakthrough curve well, showing a saturation time of ∼320 min and a removal capacity of ∼18.71 mg g under the conditions of this study. Therefore, ZSM-5 is an extremely effective adsorbent for MTBE removal and has a huge potential to be used as a reactive medium in PRBs.