Organized By

CEE Seminar Committee

Host By

Associate Professor Qianhong SHE

Topic

Chemical Separations with Porous Aromatic Frameworks

About the Seminar

The transition to sustainable technologies is intensifying the need for efficient chemical separations across both critical materials recovery and carbon management. Conventional critical element extraction methods remain environmentally damaging and difficult to scale. In parallel, the rapid growth of AI-driven data centers is increasing dependence on natural gas combined cycle (NGCC) power, intensifying CO₂ emissions. A central challenge in both areas is the dilute nature of target species, which renders separations inefficient and ineffective.

This seminar will describe the development of chemically robust adsorbents based on porous aromatic frameworks (PAFs), which combine structural stability, tunability, and resistance to harsh acidic, basic, and oxidative environments. We first present hard Lewis basefunctionalized PAFs for rare earth separations, enabling selective extraction of scandium from monazite and laterite ores with selectivity over more than 40 competing elements. Mechanistic insights are obtained through solid-state NMR, density functional theory, and Xray absorption spectroscopy, and the platform is extended to metalloid separations from industrial refining waste.

On the other hand, we introduce functionalized PAFs for carbon capture from both direct air capture and NGCC flue gas. These materials exhibit high durability over 900 adsorption– desorption cycles in oxygen-rich, humid conditions with less than 2% capacity loss, along with rapid kinetics (<10 min cycle times).

About the Speaker

Zi Hao Foo is an NTU College of Engineering International Postdoctoral Scholar based at the University of California, Berkeley. His research focuses on the design and synthesis of porous materials for separation processes relevant to sustainable energy and resource recovery. His work on critical materials centers on the selective separation and extraction of rare earth elements and metalloids, which are essential to modern electronic, energy, and manufacturing technologies.

In parallel, he develops adsorption-based processes for carbon capture, with an emphasis on both direct air capture and natural gas combined cycle systems. Zi Hao received his Ph.D. from Massachusetts Institute of Technology in 2024 and his Bachelor of Engineering from Nanyang Technological University in 2019.