Removal of single-ring aromatics by tailored zeolites

The exchange of organic ions (tailoring agents) with natural cations greatly enhances benzene, toluene, and o-xylene (BTX) adsorption of zeolites. Zeolites from four different mineral deposits are tested. Six organic ions are used as tailoring agents and their exchange and/or adsorption on the natural zeolites is evaluated. Isotherms are performed to evaluate BTX adsorption on tailored zeolites at different tailoring agent dosages.;Below the external cation exchange capacity (ECEC), long-alkyl tailoring agents show an almost complete exchange with natural cations on zeolites. The orientation of these long-alkyl cations in head-to-tail pairs on the external surface of the zeolite permits their adsorption beyond the ECEC of the zeolite. These long-alkyl tailoring agents create an effective organophilic coating where BTX are partitioned and removed from solution (o-xylene ;Short-alkyl tailoring agents show an incomplete exchange. Surface charge density of the zeolite, steric properties and high solubility of these tailoring agents account for their incomplete exchange. Zeolites tailored with the tetramethylammonium ion (TMA;Additional experimental studies show that (a) there is a synergistic effect when two or three contaminants are in solution. The adsorbed molecules of one contaminant act as a secondary solvent phase increasing the partition of the other contaminants, (b) interference on benzene adsorption occurs when a mixture of tailoring agents is used, (c) benzene adsorption capacity is an exponential function of the grain size on TMA...