A COF-supported Zn-PBA composite for the efficient removal of cesium

Abstract

In this study, the Zn-PBA/LZU1 composite was successfully synthesized by anchoring the zinc-based Prussian blue analog (Zn-PBA) nanoparticles onto a covalent organic framework (COF-LZU1) through coordination interactions. The resulting composite exhibited significantly enhanced adsorption capacity (279.15 mg g⁻¹) and rapid equilibrium attainment (20 min) for Cs⁺ compared to powdered Zn-PBA. This Zn-PBA/LZU1 exhibited remarkable selectivity for Cs⁺, even when exposed to high concentrations of competing ions such as Na⁺, K⁺, Ca²⁺, and Mg²⁺. It demonstrated consistent performance across a wide pH range (2–12). Furthermore, the composite retained an average of over 75% of its initial adsorption efficiency after five regeneration cycles, highlighting its reusability and sustainability. The experimental results suggested that the adsorption mechanism involved K⁺/Cs⁺ ion exchange.