LSU ChE, Chemistry Professors Arges & Kumar Secure $500,000 Grant
LSU Chemical Engineering Professor Chris Arges and LSU Chemistry/Center for Computation
& Technology Professor Revati Kumar were recently awarded a three-year, $500,000 grant
for their project, “Understanding and Manipulating Counterion Condensation With Charged
Polymer Electrolytes for Selective and Low-Resistant Membrane Separations.”
The project, which is funded by the Department of Energy’s Separations Science Program, will ultimately help realize the guiding principles for designing low-resistant membranes for ionic separations. These membranes are vital to the desalination, or removing salts and minerals from a target substance, of municipal and industrial water streams, in addition to removing nitrates, heavy metals, and charged pesticides and pharmaceuticals from ground water.
“Forty to 70 percent of operating and capital costs of chemical processes in a plant are related to separations,” Arges said. “There is a big incentive to lower the costs and energy associated with separations.”
Upon arriving at LSU in early 2016, Arges aimed to develop a project on investigating counterion condensation in membrane separators but concluded that he didn’t think these kinds of experiments could be done effectively in solid-state membranes. With the acknowledgment that working on such a project would be a complex and challenging task, Arges saw that working with someone with a different skill set, such as Kumar, would be beneficial.
“Her molecular simulations have the ability to peek inside the nano-confined charged domains to see how condensed and non-condensed ions transport,” Arges said. “This is a great example of two departments and colleges working together and complementing their unique skill sets.”
“I contribute toward the theory and simulation, while Chris handles the experimental side,” Kumar said.
The project investigates counterion condensation phenomena in model polymer systems and correlates it to bulk ionic charge transport and selectivity. Using the principles of directed self-assembly, the model systems are precisely defined at the molecular level and have long-range order and are free of structural defects. This is important because defects obfuscate correlations between ionic transport and counterion condensation.
The central premise of the work is that condensed counterions in the membrane migrate slower under applied electric fields, and the condensed ions aid unwanted co-ion adsorption, which compromises the selectivity of the membrane.
“Directed self-assembly of block copolymers has been primarily targeted for making the next generation of faster computer chips in your phones and computers,” Arges said. “What we’re doing now is adopting these cutting-edge techniques to understand charge transport in electrochemical materials found in batteries, fuel cells, and electrochemical separation units.”
To make the project successful, Arges and Kumar will rely heavily on the unique research capabilities and infrastructure at LSU. These facilities include LSU’s Synchrotron Radiation Research Center in the Center for Advanced Microstructures and Devices (CAMD), where Small-Angle X-ray Scattering (SAXS) studies reveal the microstructure of the precisely defined model systems. Their project will also leverage LSU’s Supercomputer, SuperMike II, which is managed by LSU’s High-Performance Computing Center.
“Most universities cannot boast that they have both a synchrotron facility for sophisticated X-ray experiments studies, in addition to having extremely fast supercomputers,” Kumar said.
Arges and Kumar recently submitted a manuscript on their results and were surprised to learn the influence that water has on counterion condensation. These results not only provide future research directions that aim to relate the extent of water solvation to the degree of condensed counterions in nano-confined domains, but will also help them understand how water management in membranes impacts desalination rates.
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Contact: Libby Haydel
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