Metal-Organic Framework Materials for the Separation and Purification of Light Hydrocarbons

The separation and purification of light hydrocarbons (LHs) mixtures is one of the most significantly important but energy demanding processes in the petrochemical industry. As an alternative technology to energy intensive traditional separation methods, such as distillation, absorption, extraction, etc., adsorptive separation using selective solid adsorbents could potentially not only lower energy cost but also offer higher efficiency. The need to develop solid materials for the efficiently selective adsorption of LHs molecules, under mild conditions, is therefore of paramount importance and urgency. Metal-organic frameworks (MOFs), emerging as a relatively new class of porous organic-inorganic hybrid materials, have shown promise for addressing this challenging task due to their unparalleled features. Herein, recent advances of using MOFs as separating agents for the separation and purification of LHs, including the purification of CH4, and the separations of alkynes/alkenes, alkanes/alkenes, C-5-C-6-C-7 normal/isoalkanes, and C-8 alkylaromatics, are summarized. The relationships among the structural and compositional features of the newly synthesized MOF materials and their separation properties and mechanisms are highlighted. Finally, the existing challenges and possible research directions related to the further exploration of porous MOFs in this very active field are also discussed.