Divalent Ion Selectivity in Capacitive Deionization with Vanadium Hexacyanoferrate: Experiments and Quantum?Chemical Computations

Selective removal of ions from water via capacitive deionization (CDI) is relevant for environmental and industrial applications like purification, softening, resource recovery. Prussian blue analogs (PBAs) are proposed as an electrode material selectively removing cations water, based on their size. So far, PBAs used in CDI selective toward monovalent ions. Here, vanadium hexacyanoferrate (VHCF), a PBA, introduced new hybrid setup to remove divalent water. These electrodes prefer Ca2+ over Na+, with separation factor, ?Ca/Na ?3.5. This finding contrasts the observed ion selectivity by PBA electrodes. opposite behavior understood density functional theory simulations. Furthermore, coating VHCF conducting polymer (poly-pyrrole, doped poly-styrenesulphonate) prevents contamination treated following degradation electrode. facile modular method can be effortlessly extended other electrodes, limiting extent during repeated cycling. study paves way tunable while extending library that successfully (selective) CDI.