Heating microporous polymers using low levels of oxygen produces a tougher and far more selective membrane which is still relatively flexible.
- Qilei Song
Newly-developed synthetic membranes provide a greener and more energy-efficient method of separating gases, and can remove carbon dioxide and other greenhouse gases from the atmosphere, potentially reducing the cost of capturing carbon dioxide significantly.
The synthetic membranes, made of materials known as polymers of intrinsic microporosity (PIMs), mimic the hourglass-shaped protein channels found in biological membranes in cells. The tiny openings in these molecular ‘sieves’ – just a few billionths of a metre in size – can be adjusted so that only certain molecules can pass through. Details are published in the journal Nature Communications.
Current methods for separating gases are complex, expensive and energy-intensive. Additionally, conventional polymers, while reliable and inexpensive, are not suitable for large scale applications, as there is a trade-off between low permeability levels and a high degree of selective molecular separation.
Researchers are attempting to develop new methods of energy-efficient and environmental-friendly membrane-separation technology, which is an essential process in everything from water purification to controlling gas emissions.
The team from the University’s Cavendish Laboratory, working with researchers from Kyoto University, has developed an alternative approach to generating polymer membranes, ‘baking’ them in the presence of oxygen, a process known as thermal oxidation.
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Image: Polymer molecular sieves with interconnected pores (in green) for rapid and selective transport of molecules
Credit: Qilei Song
Reproduced courtesy of the University of Cambridge
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