Construction of high stabilization PBAs-Cu@MS as a platform for high-efficiency and selective removal of Cs(I)

Prussian blue analogues (PBAs) are widely considered as an auspicious material for Cs+ separation to deal with water pollution. However, the noxious presence of cyanide contamination derive from the Prussian blue analogues (PBAs) in alkaline solutions presents a grave threat to environmental safety. In this study, the instability and cyanide release problems of PBAs-Cu under alkaline conditions were remedied by coating the outside of PBAs-Cu with Mesoporous Silica (MS). The newly designed PBAs-Cu@MS composite is highly stable in a wide pH range (2 ≤ pH ≤ 13), has a high Cs+ adsorption capacity (84.98 mg/g), and can effectively remove 97.1% of Cs(I) selectively, as demonstrated by systematic adsorption tests in complex wastewater systems. PBAs-Cu@MS has excellent regeneration performance to be 86.4% after 5 recycles. Furthermore, as confirmed by XRD and free cyanide analysis, even at pH 13, the crystallization and chemical stability of PBAs-Cu@MS is extremely high. MS is a useful protective element for the stabilization of PBAs. Considering its cost-effectiveness, eco-friendliness, easy preparation and efficient selective removal performance, PBAs-Cu@MS holds great promise in selective removal of Cs+ from complex wastewater systems.