Liquid‐phase selective adsorption of xylene isomers in ultramicroporous carbon spheres

Abstract

The objective of this work is to investigate adsorption separation of liquid‐phase xylene isomers using ultramicroporous carbon spheres. The synthesized glucose‐based adsorbent (UMC‐xyl) enabled the challenging separation of liquid‐phase p‐xylene/m‐xylene with an adsorption selectivity of 53 as well as p‐xylene uptake of 91mg/g, outperforming a series of commercial adsorbents including the industrial benchmark KBaX. The micropore diffusion model was used to give the best fit to the adsorption kinetics of UMC‐xyl with a rate achieved higher than KBaX. The xylene isomer separation was facilitated by the narrow ultramicropore size distributed at 5.8–6.8 Å in UMC‐xyl via a synergistic kinetic and size‐sieving separation mechanism. Breakthrough experiments confirmed the effectiveness of UMC‐xyl in the dynamic selective separation of p‐xylene from xylene isomers, together with superior multiple‐cycle eluent regenerability under the synergistic effects of the “like‐dissolve‐like” principle and π–π interaction. The work opens a new direction of using porous carbon adsorbents for continuous liquid‐phase separation of challenging hydrocarbon isomers.