Separation of diverse alkenes from C2-C4 alkanes through nanoporous graphene membranes via local size sieving

Efficient Separation of Acetylene-Containing Mixtures Using ZIF-8 Membranes

Metal-organic framework (MOF) membranes show great potential in the separation of acetylene mixtures. In this work, we have prepared ZIF-8 membranes on polyamide (PA) substrates for the highly selective separation of acetylene/methane and acetylene/carbon dioxide mixtures. The C₂H₂/CH₄ and C₂H₂/CO₂ mixtures can be successfully separated using the ZIF-8 membranes, with separation factors of 12.1 and 1.8, respectively. Based on the results of the cross-permeation tests of C₂H₂/CH₄, CO₂/CH₄, and C₂H₂/CO₂, the separation mechanism of C₂H₂/CH₄ in our ZIF-8 membrane can be attributed to a higher affinity for acetylene and molecular sieving effect, while C₂H₂/CO₂ separation is related to thermodynamic factors. It is worth noting that this is the first example of MOF membranes to successfully separate C₂H₂ from CH₄ and CO₂.

Recent Progress in a Membrane-Based Technique for Propylene/Propane Separation

The similar physico-chemical properties of propylene and propane molecules have made the separation process of propylene/propane challenging. Membrane separation techniques show substantial prospects in propylene/propane separation due to their low energy consumption and investment costs, and they have been proposed to replace or to be combined with the conventional cryogenic distillation process. Over the past decade, organosilica membranes have attracted considerable attention due to their significant features, such as their good molecular sieving properties and high hydrothermal stability. In the present review, holistic insight is provided to summarize the recent progress in propylene/propane separation using polymeric, inorganic, and hybrid membranes, and a particular inspection of organosilica membranes is conducted. The importance of the pore subnano-environment of organosilica membranes is highlighted, and future directions and perspectives for propylene/propane separation are also provided.