Efficient adsorption separation of xylene isomers using a facilely fabricated cyclodextrin-based metal–organic framework

Background Metal−organic frameworks (MOFs) are energy-efficient adsorbents for separating industrial chemical feedstocks. A type of MOF containing an extended porous network of γ-cyclodextrin (γ-CD) and alkali metal salts, CD-MOF, has potential applications in adsorption separation processes in the petrochemical industry. This study aims to present the adsorption efficiency of CD-MOF-1 in separating xylene regioisomers. Results The adsorption separation of xylene regioisomers on layered CD-MOF-1 microcrystals was studied using batch vapor-phase adsorption and liquid-phase breakthrough adsorption. CD-MOF-1 showed preferable adsorption of o -xylene over the other two isomers, with adsorption strength in the order o -xylene ( o X) > m -xylene ( m X) > p -xylene ( p X). With increased temperature, high adsorption capacities of o X and m X over p X were detected. However, this also resulted in a decrease of the separation factors of o X/ p X and m X/ p X. Conclusion The high resolution and large separation factors for o X/ p X and m X/ p X make CD-MOF-1 an efficient and reliable alternative adsorbent to the isolation protocols for xylene isomers currently used in the petrochemical industry. © 2018 Society of Chemical Industry