Ethylene adsorption on cationic surfactant modified zeolite NaY

The ethylene adsorption isotherms of zeolite NaY and their cationic surfactant modifiers, phenyl trimethyl ammonium bromide (PTAB), octyl trimethyl ammonium bromide (OTAB), hexadecyl trimethyl ammonium bromide (HTAB) and dioctadecyl dimethyl ammonium bromide (DDAB), were investigated. Zeolite NaY was synthesized and modified by cationic surfactants in the concentration range 0.1–3.0 mM. The ethylene adsorption isotherms indicated that only zeolite modified with PTAB could significantly enhance the ethylene adsorption capacity. Zeolite NaY modified with 0.5 mM PTAB was the best adsorbent and could adsorb up to 111.19 cm3 g−1 of ethylene which was equivalent to a 28.5% increase. The XRD results indicate that modification of zeolite NaY with small amount of cationic surfactants does not change the crystallinity of the starting zeolite. The elemental analysis indicated that the Si/Al ratio of synthesized zeolite NaY was close to 2. Surface area characterization showed that the BET surface area and micropore surface area of modified zeolite slightly decreased but the external surface area, pore volume and pore size diameter remained unchanged.