Published January 5, 2018
Carbon dioxide (CO₂) capture, sequestration, and utilization is an important approach to mitigating CO₂ emissions to the environment. A key strategy is to decarbonize fossil fuels before burning them. This process involves the conversion of fossil fuels into a gas mixture of hydrogen (H₂) and CO₂, which must then be separated to obtain CO₂ for sequestration/utilization and H₂ fuel for use. Membrane technology has inherent advantages for this separation because of its high energy efficiency, small footprint, and ease of scale-up.
Lingxiang Zhu, a PhD student from Dr. Haiqing Lin’s group, has been focusing on the development of high-performance membranes for H₂ purification and CO₂ capture since 2014. His recent research demonstrated a new approach to manipulating polymer structure by acid doping, leading to superior H₂/CO₂ separation performance. Specifically, polybenzimidazole (PBI) was doped with polyprotic acids such as phosphoric acid and sulfuric acid. These acids cross-link PBI backbones, enhance chain packing efficiency, and drastically decrease free volume, improving the H₂/CO₂ selectivity to an unprecedented value of 140 at 150 °C. This selectivity is the highest among known polymers. The simple yet elegant approach of acid doping provides a flexible and exciting platform to enhance polymer chain-packing efficiency, and thus achieve sharp molecular size separation in polymers. The work was published in Energy & Environmental Science, which is a monthly journal published by the Royal Society of Chemistry with an impact factor of 29.5. [Read the full paper]
Lingxiang just defended his thesis entitled “Advanced polymeric membranes for H₂ purification and CO₂ capture” in December 2017, and he will start a postdoctoral training in coming summer. He plans to pursue an academic career, focusing on education and research in chemical engineering and membrane technology.