Selective adsorption properties and stable solidification of CS by insoluble ferrocyanide loaded zeolites

Yuki Ikarashi, Rana Syed Masud, Tomonori Nakai, Hitoshi Mimura, Eiji Ishizaki, Minoru Matsukura, Yoshinobu Hosoi

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Citation (Scopus)

Abstract

In Fukushima NPP-1, large amounts of high-activity-level water (HALW) accumulated in the reactor, turbine building and the trench in the facility is treated by circulating injection cooling system. The development of highly functional adsorbents and stable solidification method contributes to the advancement of the decontamination system and environmental remediation. The present study deals with (1) preparation of insoluble ferrocyanide loaded zeolites, (2) selective uptake of Cs+ in seawater, (3) estimation of Cs immobilization ratio and stable solidification. Various kinds of Cs-selective composites loaded with insoluble ferrocyanides (CoFC, NiFC) into the zeolites (zeolite A (A51, A-51J), zeolite X (LSX), chabazite (modified chabazite) and natural mordenite (SA-5)) matrices have been prepared using successive impregnation/precipitation methods by Tohoku University. As for Cs+ adsorption, these composites had relatively large uptake (%) above 95%, distribution coefficients (Kd) above 103 cm3/g and excellent adsorption kinetics even in seawater. The immobilization ratio (%) of Cs for the CoFC saturated with Cs+ was estimated at different calcination temperatures up to 1,200°C in advance. The immobilization ratio was less than 0.1% above 1,000°C, indicating that the adsorbed Cs + ions are completely volatilized and insoluble ferrocyanides had no immobilization ability for Cs. In contrast, the insoluble ferrocyanide-loaded zeolites had excellent Cs immobilization ability; in the case of insoluble ferrocyanide-loaded natural zeolites (NiFC-SA-5, CoFCmodified chabazite), the immobilization ratio was above 99% and 96% even after calcination at 1,000°C and 1,100°C, respectively, indicating that nearly all Cs ions are immobilized in the sintered solid form. On the other hand, the immobilization ratio for the insoluble ferrocyanide-loaded A and X zeolites (NiFC-A (A51, A51J), NiFC-X) tended to decrease with calcining temperature; for example, the immobilization ratio for NiFC-X at 1,000°C and 1,100°C was estimated to be 74.9% and 55.4%, respectively, and many spots concentrating Cs were observed on the surface. The difference in immobilization behavior between natural zeolites and synthetic ones is probably due to the phase transformation and surface morphology at higher temperature above 1,000°C. The stable solidification of insoluble ferrocyanides was thus accomplished by using the excellent Cs immobilization abilities of zeolite matrices (Cs trapping and self-sintering abilities).

Original languageEnglish
Title of host publicationFuel Cycle, Radioactive Waste Management and Decommissioning; Reactor Physics and Transport Theory; Nuclear Education, Public Acceptance and Related Issues; Instrumentation and Controls; Fusion Eng.
PublisherAmerican Society of Mechanical Engineers (ASME)
ISBN (Print)9780791855829
DOIs
Publication statusPublished - 2013
Event2013 21st International Conference on Nuclear Engineering, ICONE 2013 - Chengdu, China
Duration: 2013 Jul 292013 Aug 2

Publication series

NameInternational Conference on Nuclear Engineering, Proceedings, ICONE
Volume5

Other

Other2013 21st International Conference on Nuclear Engineering, ICONE 2013
CountryChina
CityChengdu
Period13/7/2913/8/2

ASJC Scopus subject areas

  • Nuclear Energy and Engineering

Fingerprint Dive into the research topics of 'Selective adsorption properties and stable solidification of CS by insoluble ferrocyanide loaded zeolites'. Together they form a unique fingerprint.

Cite this