Efficient adsorbents to remove the trace alcohol from Fischer Tropsch mixed olefins: Insights into the adsorption enhancement by hydrogen bonding on etched NaX

An efficient alcohol adsorbent has been prepared by the NaOH etching of Na-FAU zeolite and applied for the deep removal of the alcohol from FT-mixed olefins. Due to the NaOH etching, the adsorption capacity of the NaX-2 adsorbent (85 mg/g) for n-butanol was significantly higher than the NaX adsorbent (42 mg/g). As demonstrated by SEM, 29 Si NMR, 27 Al-NMR, CO 2 -TPD, and N 2 adsorption–desorption, the etching of zeolite NaX occurs at the grain boundary, which leads to more mesopores, increased weak base sites, and Si(3Al) structure formation by alkali etching, facilitating alcohol diffusion and improving the adsorption through hydrogen bonding. In-situ FTIR and molecular simulations were employed to demonstrate the adsorption models of alcohols over Na-FAU zeolite. The hydrogen bonding network formed by dealumination finally enhances the alcohol adsorption by the hydrogen bonding by O al -H al ‧‧‧O zeo and O zeo -H zeo ‧‧‧O al . This work provides a facile preparation method for removing trace alcohol from olefins, giving promising guidance for industrial applications.