Adsorption of MTBE from contaminated water by carbonaceous resins and mordenite zeolite

Abstract

Equilibrium and kinetic adsorption of methyl tert-butyl ether (MTBE) onto two carbonaceous resins and one zeolite was elucidated in this study. The Freundlich isotherm is adequate for describing the adsorption equilibrium of MTBE onto all the tested adsorbents in deionized water and natural waters. The resins of Ambersorb 563 and 572 have the highest adsorption capacity and almost twice the capacity of mordenite in deionized water. A different extent of NOM competition with MTBE was found for the carbonaceous resins in natural waters. For mordenite, no competitive adsorption was observed in natural water. The ideal adsorbed solution theory combined with equivalent background compound (IAST-EBC) model successfully described and predicted the adsorption of MTBE onto the carbonaceous resins in natural waters. The pore diffusion and micropore diffusion model fit the experimental data fairly well and successfully predicted the transport of MTBE within the adsorbent under different operating conditions. The small tortuosity factor between 1.2 and 2.3 of the resins for the diffusion of MTBE was observed, indicating a superior transport property for the carbonaceous resins in natural waters. The intracrystalline diffusivity of MTBE in natural water was much slower than that in deionized water, only 1/10 in STL and 1/3 in FS natural water, since the aperture entrances of mordenite was appreciably hindered by NOM.