Development of adsorption and solidification process for decontamination of Cs-contaminated radioactive water in Fukushima through silica-based AMP hybrid adsorbent

Autor: Hitoshi Mimura, Xiaoxia Zhang, Yan Wu, Yuezhou Wei
Rok vydání: 2017
Předmět:
Zdroj: Separation and Purification Technology. 181:76-84
ISSN: 1383-5866
DOI: 10.1016/j.seppur.2017.03.019
Popis: Developing highly efficient cesium (Cs) adsorbent and a stable solidification method for Cs is vital for the advancement of the decontamination system for Fukushima Daiichi Nuclear Power Plant. A novel porous silica loaded with ammonium molybdophosphate (AMP/SiO 2 ) was prepared through impregnation/precipitation/freeze-drying method. The composite with 32.4 wt% AMP loading amount had superior large 254.2 A pore width and 72.2 m 2 /g surface area. The 137 Cs removal efficiency in actual seawater was 97.1% within 30 min, indicating that AMP/SiO 2 effectively treated contaminant water with low-level concentration of Cs even in the presence of highly concentrated competing ions. The AMP/SiO 2 adsorption of 137 Cs in seawater conformed well with Redlich-Peterson model. The ion exchange ratio of Cs + and NH 4 + in AMP was estimated to be 71% from the equivalent of Cs 2 NH 4 MP. Pyrogenetic AMP/SiO 2 -adsorbed Cs (Cs-AMP/SiO 2 ) was decomposed above 400 °C sintering temperature, and Cs immobilization (%) decreased from 100% to 40% after sintering at 1200 °C; porous silica support matrix had no immobility for Cs. In contrast, adding natural mordenite (NM) can depress the volatilization of Cs, resulting to the steady immobilization ratio of Cs at nearly 100% for the sintered products. The crystal phase immobilizing Cs was identified as Cs 4 Al 4 Si 20 O 48 through X-ray diffractometry. The Cs leachability from the sintered products was less than 0.1% even at 90 °C in distilled water and 0.1 M sodium chloride.
Databáze: OpenAIRE
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