Whisky clearing graphene by Malayali professor Rahul Nair

ALAPPUZHA: A research team led by Malayali professor Rahul Nair in a UK university has developed a graphene-oxide membrane that  makes whisky clear, paving the way for new commercial application of graphene membrane. Dr Rahul Nair, 34, is professor at the National Graphene Institute and School of Chemical Engin-eering and Analytical Science at the University of Manchester, U.K. The latest research report published in Nature Materials on November 13 said that the newly developed membrane allowed  alcohol to pass through and remove the larger molecules, which gives the amber colour to whisky. Dr Nair, who hails from  Kuttanperoor near Ma-nnar here, told Deccan Chronicle in an online interaction that the new research would help them  expand the applications of grapheme-based membranes from sea water desalination to organic so-lvent nanofiltration.

Unlike sea water desalination, which separates salt from water, OSN technology separates charged or uncharged organic compounds from an organic solvent. It has been proved that graphene-oxide membranes can be designed to remove various organic dyes as small as a nanometre dissolved in methanol. “We filtered whisky and cognac (a kind of brandy) through the graphene-oxide membrane. As a result, we concluded that the membrane allowed the alcohol to pass through, removing the larger molecules that gives it amber colour. The clear whisky smells similar to the original whisky. We are not allowed to drink it in the lab. However it was a funny Friday night experiment,” he said.

Dr Rahul Nair

The membranes not only filter out small molecules but also boost the filtration efficiency by increasing the solvent flow rate. Chemical separation is all about energy. Various chemical separation proc-esses consume about half of industrial energy usage. Any new efficient separation process will minimise the consumption of energy, which is in high demand now. By 2030, the world is projected to consume 60 per cent more energy than today. So this new development opens an opportunity to separate molecules from different organic solvents for chemical and pharmaceutical industries. Most of the existing polymer-based membranes are unstable in organic solvents whereas the new graphene-oxide membrane is highly stable,  he said.

This is the third significant breakthrough during the course of his team’s mission for sea water desalination with grapheme-based membranes which began in 2010. In 2014, his team  developed a kind of ‘wonder’ paint from graphene that could banish rust forever while they found that multilayer films made from graphene oxide were vacuum-tight under dry conditions in 2012. Graphene-oxide membranes have attracted widespread attention for water filtration and desalination applications, providing a potential solution to  water scarcity. By using ultra-thin membranes, this experiment has shown how other solvents can be filtered out, proving that there is potential for organic solvent nano-filtration. Dr Nair, alumnus of School of Pure and Applied Physics (SPAP) of Mahatma Gandhi University, took  PhD form the University of Manchester in 2010.