Stabilization of Prussian blue analogues using clay minerals for selective removal of cesium

Numerous Prussian blue analogues (PBAs) and their application in cesium elimination have been conducted. However, those were practically impossible to use in alkaline solution and seawater, due to the low stabilization of PBAs in alkaline solution and quickly decompose to create toxic cyanide contamination. In this research, potassium zinc hexacyanoferrate (PZH), one kind of PBAs was chosen, and the stability of PZH in the alkaline solution was remedied by incorporating magnetic rectorite (MR) and evaluated by XRD, XPS and cyanide analysis. Effect of pH value and the water systems on the crystalline and chemical stability were studied. The adsorption performance for Cs+ in high pH solution and the biological toxicity of the PZH/MR composite were also evaluated. The composite material exhibits significant adsorption capacity for Cs+ ions (215.128 mg/g, 293 K, increased over 20% than pristine PZH) and low cytotoxicity in human hepatic cells (HepG2 cells), indicating its potential application Cs+ adsorption in waste-water and Cs+ decorporation from body. The stability and safety mechanism in a wide pH range (from 2 to 11) were explained. The stabilization method on PBAs is an advanced yet and effective feasible mean with applications for internal and external cesium remediation. This research opens up a wide range of novel applications for PB-based adsorbents or decorporation, particularly in the field of the cesium remediation in high pH value.