A new way for the optimal isolation of propylene from propane, producing only propylene has been identified by researchers from the Texas A&M University. The process, called counter diffusion, involves individual applications of metal ions and organic ligands to the film, instead of using a mixture to coat it. With high metal ion concentration inside the film, ligands remain highly concentrated outside the film, while counter diffusing in various directions.
Texas A&M University chemical engineering associate professor Hae-Kwon Jeong said: "This is the first report where we demonstrate that a very high selectivity and a very high flux of these gas molecules is possible. "This is a simple technique that allows us to prepare high-quality, very-thin sieve MOF [metal organic framework] membranes in a potentially economic and scaleable manner. "The objective is to be able to make small, thin films in a rapid manner, but also to be able to make the grain boundary very intimate."
The traditional production process involves conversion of gases into liquid, which is then distilled. The small amount of propylene is then filtered using a membrane in a MOF.
The new technique is said to be more efficient and environmentally friendly, requiring less carbon-based fuels for distillation.
Jeong added: "Up to 80% of energy costs go just to separating chemicals, often using conventional distillation.