Collaborative Research: Selective Electrochemical Removal of Scale-Forming Mg2+ Ions in Sustainable and Energy-Efficient Water Pretreatment

One of the major challenges in water treatment and desalination is scaling—the buildup of insoluble mineral deposits that reduce the efficiency and lifespan of treatment systems, much like limescale in household appliances. Current methods to mitigate scale formation often rely on chemical additives such as softeners and antiscalants, which generate chemical waste and consume large volumes of water. This collaborative project will develop new classes of vanadium oxide layered materials for selective removal of magnesium ions, the dominant scale-forming species in the water, using electrochemical methods for energy-efficient water pre-treatment. The technology is expected to surpass the performance and sustainability challenges of current water pretreatment technologies. The project will offer cross-disciplinary training opportunities for students in chemical engineering, materials science, and computational chemistry. The investigators will actively recruit and mentor students to foster a research environment that encourages collaboration and innovation in addressing global water challenges. This project will explore electrochemical pretreatment strategies to remove divalent scale-forming cations (SFCs), such as magnesium, using intercalative electrode materials, including vanadium oxides with a controlled interlayer distance for ion transport and a tailored electrode local structure to encourage Mg²⁺ ion intercalation against competing Na⁺ ions. The team will integrate material synthesis, electrochemical testing, advanced atomistic simulations, and in situ synchrotron X-ray techniques to test the following three hypotheses: (i) narrow interlayer spacing of α-V2O5 (<5 Å) will selectively uptake small-size Mg²⁺ over large-size Na+, (ii) introducing electronegative dopant to α-V2O5 will weaken the lattice oxygen charge to alleviate the electrostatic interaction between electrode and Mg²⁺ ions to favor Mg²⁺ transport; and (iii) disordered local structures of the host materials (e.g., turbostratic disorder) will decrease Mg²⁺ transport barrier. The research outcomes hold promise for the electrochemical removal of Mg²⁺ from water using high-capacity intercalative battery electrode materials, which could address longstanding challenges in selectivity and structural stability under aqueous conditions, leading to a sustainable and energy-efficient electrochemical water pretreatment system. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.