Small Differences, Big Impact: Achieving Effective Selective Separations from Water by Tuning Ion Transport Processes

Objective

"Selective ion separation plays a crucial role in Selective ion separation plays an important role in water treatment, resource recovery, and agriculture. As the need for sustainable water use intensifies and global demand for strategic resources like lithium increases, developing efficient and selective ion separation technologies becomes essential. In particular, the selective separation of ions with similar properties, such as sodium (Na+) and potassium (K+), remains a significant challenge. In the ION-TRACE project, I aim to overcome this challenge by developing innovative separation processes. My approach involves pioneering electro-driven processes, including Battery Deionization (BDI) combined with Concentration-Dependent Switching (CDS) and Electrochemical Ion Pumping (EIP). These processes take advantage of differences in ion adsorption and desorption dynamics to separate two similar ions. The methodology of this project focuses on understanding ion transport mechanisms, which create specific time differences in ion adsorption and desorption, and identifying strategies to optimize these mechanisms to reach the operational ""sweet spot."" First, I will demonstrate that even a limited selectivity of robust materials can be sufficient to achieve highly efficient ion separation. Next, I will tune the process through the introduction and modification of ion-selective electrodes and membranes, modifications to material structure, and optimizations of process configurations. Synthesized materials will be studied in detail to assess their stability, selectivity, and transport properties under varying experimental conditions, including salinity, pH, presence of complex ion mixtures, and applied electrical field. By achieving selective separation of similar ions from complex mixtures, ION-TRACE will represent a significant leap in this research field, and provide societal benefits, such as reduced freshwater consumption and enhanced resource independence for Europe. "