C₈ Aromatics competitive adsorption on zeolites using the headspace technique

Abstract

Liquid phase adsorption of C8 aromatics, p-xylene and m-xylene, in the presence of toluene, on NaY, KY, BaX, and BaY zeolites was investigated by headspace gas chromatography. Effects of temperature on the adsorption were studied by varying the operating temperature from 40 °C to 120 °C. Mixture compositions were also varied from 1.25 wt.% to 20 wt.%. Using the headspace technique, it was found that toluene affected the adsorption information due to its high vapor pressure. The adsorbed amounts of p-xylene and m-xylene increase when the temperature increases from 40 °C to 100 °C. The KY, BaX, and BaY zeolites selectively adsorb p-xylene for all studied conditions, while the NaY zeolite selectively adsorbs m-xylene at some studied conditions. The effects of the zeolites could be clearly seen at the high p-xylene and m-xylene concentrations. The KY zeolite gave the highest p-xylene selectivity followed by BaX, Bay, and NaY zeolites, respectively.