Stable poly(vinyl alcohol) and alginate cross-linked granules with immobilized ferric hexacyanoferrate for cesium removal from waters

• Published in: Journal of the Taiwan Institute of Chemical Engineers 2019-02, Vol.95, p.1-10
• Main Authors: Tsai, Cheng-Jui, Chang, Yin-Ru, Chen, Man-Li, Lo, Yu-Kuo, Lee, Duu-Jong
• Format: Article
• Language: English
• Subjects: Cesium; Granules; Prussian blue; Stability
• ISSN: 1876-1070; 1876-1089
• DOI: 10.1016/j.jtice.2018.09.028

•Shape stable PVA granules were synthesized using extended 2nd crosslinking stage.•Agents for 2nd crosslinking included sulfate, phosphate, and nitrate.•Produced granules have qmax of Cs ions 76.8–87.6 mg/g PB.•Produced granules can be stored at dry conditions.•Produced granules can be effective radioactive Cs barrier for waterworks. The poly(vinyl alcohol) (PVA) granules can immobilize Prussian blue (PB) nanoparticles to form efficient cesium adsorbent. This paper for the first time produced the PVA-PB granules with shape stability at drying-re-wetting cycles by crosslinking PVA, alginate and PB drops with boric acid (PVA-B) followed by extended crosslinking of the formed granules with nucleophiles, 6 hr for phosphate (PVA-P), 12 hr for sulfate (PVA-S), and > 12 hr for nitrate (PVA-N). The qmax values for the yielded PVA granules ranged 76.8–87.6 mg/g PB. The PVA-B matrix has effective diffusivity for Cs ions at 7% of that in the bulk water. The PVA-P has similar diffusivity with PVA-B, while the PV-S and PVA-N have further reduced internal diffusivities (by 46% and 67%, respectively). Repeated washing can minimize the hexacyanoferrate release potential from the PVA granules. The present dried, nucleophile-crosslinked PVA granules can be stored for long time period and can be used directly as the “first-aid” radioactive Cs barrier for waterworks and pipeline stations when meeting urgent radioactive threats. Synthesis of shape stable PVA-PB granules under drying and re-wetting cycles [Display omitted]