A team of Vanderbilt researchers have developed novel technology called electrochemical ion pumping (EIP) that could revolutionize the treatment of water and resource extraction.
The research, published in the Oct. 1 issue of Nature Water, overcomes a critical limitation in the commonly used process of conventional electrosorption, which uses electrodes to adsorb and remove ions from water. According to the researchers, the practical use of electrosorption has been limited by the need for alternating charging and discharging cycles due to limited electrode capacity. During these frequent switches, residual solutions in the electrodes mix with incoming solutions, which reduces energy efficiency and ion removal effectiveness.
However, the new EIP process addresses this long-standing problem by implementing an innovative circuit-switching approach. Unlike traditional methods, EIP allows for continuous, unidirectional ion flow without disruptive solution switching. This eliminates mixing, reduces operational complexity, and enhances separation performance, the researchers said.
EIP can also operate with very short charging-discharge cycles, which limits unwanted side reactions and opens new possibilities for electrode design, focusing on properties that enhance ion separation rather than just adsorption capacity.
"We've effectively solved one of the major bottlenecks in electrosorption," said Longqian Xu, the lead researcher and co-inventor of the process. "By eliminating mixing during solution switching, EIP can be used across a wide range of environmental applications with improved performance."
Shihong Lin, associate professor of civil and environmental engineering and corresponding author of the paper, said the potential for EIP extends far beyond desalination.
"Anything conventional electrosorption can do, EIP can potentially do far better," said Lin, who is hopeful the platform will generate excitement within the electrochemical separation research community.
Potential applications include selective contaminant removal, water softening, nutrient recovery from wastewater, and metal extraction from natural brines and industrial wastewaters.
Lin, an environmental engineer, was a winner of the Walter L. Huber Civil Engineering Research Prize by the American Society of Civil Engineers and the Paul L. Busch Award by the Water Research Foundation. He was recognized for his contributions in advancing fundamental understanding of and developing innovative technologies for water separation processes to address critical challenges in water and resource sustainability.
The work, funded by the Office of Naval Research, is a collaboration between the Vanderbilt team and the research team led by Zheng Chen, associate professor of nano-engineering at UC San Diego's Jacobs School of Engineering.
