Chemical Engineers Addressing Climate Change

CO­₂ emissions from burning of fossil fuels are the driving force behind global climate change. Thus, mitigating CO­₂ emissions while providing the energy demanded by our society is one of the grand challenges facing humanity. As fossil fuels continue to serve as a major energy source, CO­₂ capture for utilization and sequestration (CCUS) is a critical need. While the solutions require a concerted effort from every discipline, chemical engineers armed with distinctive expertise in mass transfer and reaction engineering are at the forefront of efforts to address this issue. The Department of Chemical and Biological Engineering at the University at Buffalo has a cohort of research groups developing holistic approaches for CCUS, including Professors Chong Cheng, Elina Kyriakidou, Haiqing Lin, Carl Lund, Mark Swihart, Gang Wu, and Miao Yu. The synergistic collaborations of these groups have attracted more than $10 million of research funding from federal agencies, such as the Department of Energy (DOE) and the National Science Foundation (NSF).

The three main categories of carbon capture technologies include precombustion capture, post-combustion capture, and direct air capture. In the precombustion process, fossil fuels are reformed or gasified to produce H­₂ and CO­₂. Separation of H­₂ and CO­₂ enables H­₂ production with CO­₂ capture. Lin and Swihart’s groups have been developing membranes with superior H­₂/CO­₂  separation properties, including polymeric organosilica membranes (ACS Nano, 15, 12119 (2021)) and nanocomposite membranes containing Pd-based nanowires (Journal of Materials Chemistry A, 9, 12755 (2021)). In post-combustion capture, the Yu group has been developing graphene oxide- or carbon nanotube (CNT)-based membranes for CO­₂ /N­₂ separation (Advanced Functional Materials, 30, 2002804 (2020)), and Cheng and Lin’s groups are developing highly polar polymers (Joule, 3, 1881 (2019)) and mixed matrix membranes containing nanocages (Journal of Membrane Science, 606, 118122 (2020)). Both Lin and Yu’s groups have also been developing sorbents to directly extract CO­₂  from the air, one of the few technologies that can directly reduce the CO­₂  content from the atmosphere.

Another key step for CCUS technologies is to utilize CO­₂  to produce useful chemicals or fuels at low-cost, which is inherently challenging because of the chemical stability of CO­₂. To this end, a variety of approaches are being explored, and the Department is well-positioned to tackle the challenge with expertise in thermal catalytic, electrochemical, and biological reactions. For example, the Yu group developed dehydration membrane reactors to convert CO­₂ to fuels (Science, 367, 667 (2020)) and a process to produce dimethyl ether from CO­₂ and H­₂ (Journal of Materials Chemistry A, 9, 2678 (2021)); Swihart, Kyriakidou, and Lund are developing dry methane reforming catalysts to convert CO­₂ and CH­₄ to syngas (H­₂ and CO) (ACS Appl. Mater. Interfaces, 13, 17618 (2021)); and the Wu group is developing single atomic metal electrocatalysts for selective CO₂ reduction to CO and C­₂H­₄. CO­₂ can also be used to grow microalgae, which can then be used to produce nutrients and fuels. The Lin group is working with Helios-NRG, LLC (headed by Dr. Ravi Prasad, a CBE alumnus) to develop energy-efficient membranes for algae dewatering, an energy-intensive step in algae production. The world-class CCUS research efforts in the CBE@UB serve as magnets to attract undergraduate, graduate, and postgraduate researchers. They provide training opportunities for these future leaders to tackle this grand challenge faced by our generation and those to come.