Prussian blue analog-based ionic liquid for highly efficient cesium removal from wastewater

Abstract

Radioactive cesium isotopes constitute a significant fraction of nuclear wastewater contaminants, and the high solubility of cesium as an alkali metal poses challenges to its separation. Utilizing Prussian Blue Analogs (PBAs) for adsorption is an effective strategy for cesium removal, yet there is a paucity of research on PBAs-based ionic liquid for enhancing cesium adsorption performance. In this study, a Prussian Blue Analog-based ionic liquid (IPBA) constructed from tetradecyl trimethyl ammonium (TTAB) was introduced and synthesized for the adsorption of cesium. Batch adsorption experiments indicate that the IPBA consistently achieves over 95 % cesium removal across a broad pH spectrum (pH = 2–12), exhibiting excellent stability. The coordination adsorption mechanism of IPBA is confirmed through the use of XPS, FT-IR, and XRD analyses. The incorporation of hydrophobic long chains significantly enhances the selectivity of IPBA for alkali metals, such as potassium (K⁺) and sodium (Na⁺), with a cesium removal efficiency of 98.02 % even in the presence of competing ions at certain concentrations. Column adsorption experiments reveal that IPBA can efficiently remove cesium (99.24 %) within 12 h, even at a higher flow rate of 0.56 mL·s⁻¹. This research offers insights into the design and synthesis of PBAs-based ionic liquid and highlights the potential of ionic liquid in customizing the properties of PBAs for targeted environmental remediation applications.