Effectiveness of high-silica zeolites for the adsorption of methyl tertiary-butyl ether from natural water

MTBE adsorption isotherm data were collected for a matrix of high-silica zeolites with different pore sizes (ZSM-5/silicalite, mordenite, beta, Y), exchangeable cations (H⁺, Na⁺, NH₄⁺), and hydrophobicities (SiO₂/Al₂O₃ ratios). MTBE adsorption capacities of high-silica zeolites were compared with those of one coconut-shell-based and two coal-based granular activated carbons (GACs) as well as a carbonaceous resin. Isotherm experiments were conducted in ultrapure water buffered at pH 7.2 and in Tar River water (Greenville, NC) to determine the effects of co-adsorbing and preloaded natural organic matter (NOM) on MTBE adsorption. The results of this study showed that (1) high-silica zeolites with small pores (ZSM-5/silicalite, mordenite) exhibit higher MTBE adsorption capacities than GACs, (2) NOM has little or no effect on MTBE adsorption capacities of ZSM-5/silicalite zeolites, and (3) equilibrium model results suggest that silicalite-based adsorption systems are cost-competitive with activated-carbon-based adsorption systems while offering operational advantages such as longer adsorber life and possibly greater ease of regeneration.