Separation of C2 Hydrocarbons by Porous Materials: Metal Organic Frameworks as Platform

The effective separation of small hydrocarbon molecules (C-1 - C-4) is an important process for the petroleum industry, determining the end price of many essential commodities in our daily lives. Current technologies for separation of these molecules rely on energy-intensive fractional distillation processes at cryogenic temperature, which is particularly difficult because of their similar volatility. In retrospect, adsorptive separation using solid-state adsorbents might be a cost-effective alternative. Several types of solid-state adsorbents (e.g., zeolite molecular sieves) were tested for separation of small hydrocarbon molecules as a function of pressure, temperature, or vacuum. Among different types of plausible adsorbents, metal organic frameworks (MOFs), a class of porous, crystalline, inorganic-organic hybrid materials, is particularly promising. In this brief comment article, we discuss the separation properties of different types of solid-state adsorbents, with a particular emphasis on MOF-based adsorbents for separation of C-2 hydrocarbon molecules.