Researchers from the Department of Chemical Engineering, working with an international team led by KU Leuven, have developed a membrane technology to improve the efficiency of purifying widely used solvents.
The researchers show how water can be separated more quickly from isopropanol, a solvent used worldwide in the pharmaceutical and electronics industries. The results, published in Nature Communications, offer an alternative to current purification methods that require high energy input.
Separating chemical mixtures into pure components is a crucial but energy-intensive process in industrial chemistry, accounting for 10 to 15% of global energy use. One example is the purification of isopropanol, a widely used solvent in sectors such as pharmaceuticals and electronics. Current purification methods, mainly based on heating and distillation, have a significant impact on both energy consumption and CO₂ emissions in the chemical industry.
Professor Bart Van der Bruggen, lead researcher on the project at KU Leuven, said: "With the growing demand for more sustainable production processes, more efficient separation techniques are essential to continue using isopropanol—also in its bio-based forms from renewable resources—on a large scale."
Not too small, not too large
The research team developed a new type of membrane based on graphene oxide, a material made of ultrathin carbon layers. By combining conventional graphene oxide sheets with new variants containing smaller pores, they created an internal structure with two functions: narrow channels that block larger molecules and regions that attract and allow water to pass through.
Lei Jiang, a doctoral researcher at KU Leuven, said: "The main challenge is to design a structure where the channels are not too small, which would slow down the separation and require more energy, but also not too large, which would reduce the purity of the final product.
"The new membrane combines both efficient and high-quality separation in a single structure."
Dr Pengrui Jin , a Prize Fellow and researcher in the Department of Chemical Engineering and an independent principal investigator on the study, said: "The new membrane efficiently removes water from a mixture containing 90% isopropanol and 10% water. It selectively transports the water through the membrane, producing a permeate containing about 99.6% water. In addition, the process is faster than existing techniques and requires less energy, as it does not rely on high temperatures."
Broad applicability
"The membrane delivers gains across the board: purity, energy consumption and economic efficiency," added Professor Van der Bruggen.
"We are eager to test the technology on other chemical mixtures as well."
Thanks to the combination of high purity levels and lower energy demand, this new membrane could support the transition toward a more climate-friendly chemical industry. The researchers are currently exploring options to scale up the technology and are assessing the possibility of filing a patent.
