US researchers have
made molecular sieving fibres that open up new possibilities for large scale chemical separations that use much less energy than conventional distillation methods.
Sankar Nair and his Georgia Institute of Technology team have shown their metal–organic framework (MOF)-lined fibres can perform similarly to distillation in separating propylene and propane. That¡¯s the same post-cracking raw mixture that the majority of the 77 million tonnes of propylene produced in 2011 was distilled from. ¡®The degree of separation by the membrane is comparable, but uses vastly less energy,¡¯ Nair says.
Zhiping Lai, a chemical engineer from the King Abdullah University of Science and Technology in Saudi Arabia, says this result ¡®beautifully demonstrates¡¯ that ZIF-8 membranes can be produced in bulk quantities on cheap supports. ¡®Replacing distillation by an efficient membrane process can cut energy use up to 80%,¡¯ Lai says. ¡®It significantly increases the economic viability of the membrane process, which may lead to a technical revolution in the chemical industry.¡¯