Surface Modification of Bentonite for the Improvement of Radionuclide Sorption

다국어 초록 (Multilingual Abstract)

Bentonite is the most probable candidate to be used as a buffer in a deep geological repository with high swelling properties, hydraulic conductivity, thermal conductivity, and radionuclide sorption ability. Among them, the radionuclide sorption ability prevents or delays the transport of radionuclides into the nearby environment when an accident occurs and the radionuclide leaks from the canister, so it needs to be strengthened in terms of long-term disposal safety. Here, we proposed a surface modification method in which some inorganic additives were added to form NaP zeolite on the surface of the bentonite yielded at Yeonil, South Korea. We confirmed that the NaP zeolite was well-formed on the bentonite surface, which also increased the sorption efficiency of Cs and Sr from groundwater conditions. Both NaP and NaX zeolite can be produced and we have demonstrated that the generation mechanism of NaX and NaP is due to the number of homogeneous/heterogeneous nucleation sites and the number of nutrients supplied from an aluminosilicate gel during the surface modification process. This study showed the potential of surface modification on bentonite to enhance the safety of deep geological radioactive waste repository by improving the radionuclide sorption ability of bentonite.

참고문헌 (Reference)

1 이승엽 ; 김수진, "양이온성 계면활성제로 표면개질된 몬모릴로나이트의 탈수 특성" 한국광물학회 15 (15): 305-314, 2002

2 김정배, "양이온 계면활성제인 OTABr로 표면 개질한 Bentonite 흡착제에 의한 비소(As) 제거에 관한 연구" 한국수처리학회 26 (26): 55-67, 2018

3 이종표 ; 최희주 ; 최종원 ; 이민수, "국산 압축벤토나이트 완충재의 첨가제 혼합을 통한 열전도도 향상" 한국방사성폐기물학회 11 (11): 11-21, 2013

4 S. Hong, "Top-Down Synthesis of NaP Zeolite From Natural Zeolite for the Higher Removal Efficiency of Cs, Sr, and Ni" 11 (11): 252-, 2021

5 M. Kim, "Thermochemical Changes on Swelling Pressure of Compacted Bentonite" 151 : 107882-, 2021

6 S. Yoon, "Thermal Conductivity of Korean Compacted Bentonite Buffer Materials for a Nuclear Waste Repository" 11 (11): 2269-, 2018

7 M.N. Gray, "The Influence of Sand Content on Swelling Pressures and Structure Developed in Statically Compacted Na-bentonite" Atomic Energy of Canada Limited 1984

8 L.H. Johnson, "The Disposal of Canada’s Nuclear Fuel Waste: Engineered Barriers Alternatives" Atomic Energy of Canada Limited 1994

9 Ch. Baerlocher, "The Crystal Structure of Synthetic Zeolite Na-P1, an Isotope of Gismondine" 135 (135): 339-354, 1972

10 ONDRAF/NIRAS, "Technical Overview of the SAFIR 2 Report: Safety Assessment and Feasibility Interim Report 2" ONDRAF/NIRAS 2001

11 Z. Huo, "Synthesis of Zeolite NaP With Controllable Morphologies" 158 : 137-140, 2012

12 김초롱 ; 류원석 ; 주창환 ; 김주희 ; 전한용, "Swelling Behavior Evaluation of Bentonite with Additives Mixture" 한국섬유공학회 46 (46): 326-333, 2009

13 U. Håkansson, "Structure of a High-silica Variety of Zeolite Na-P" C46 : 1363-1364, 1990

14 G. Harvey, "Structure and Properties of Aluminosilicate Solutions and Gels" American Chemical Society 398 : 49-65, 1989

15 S. Hansen, "On the Crystal Chemistry of NaP Zeolites" 13 (13): 276-280, 1993

16 B.R. Albert, "Investigations on P Zeolites: Synthesis, Characterization, and Structure of Highly Crystalline lowsilica NaP" 21 (21): 133-142, 1998

17 M.V. Villar, "Hydraulic Properties of Montmorillonite-quartz and Saponite-quartz Mixture" 9 (9): 1-9, 1994

18 Japan Nuclear Cycle Development Institute, "H12: Project to Establish the Scientific and Technical Basis for HLW Disposal in Japan: Supporting Report 2" 1999

19 P. Sharma, "GISNaP1Zeolite Microspheres as Potential Water Adsorption Material: Influence of Initial Silica Concentration on Adsorptive and Physical/topological Properties" 6 : 22734-, 2016

20 U.O. Aroke, "Fourier-transform Infrared Characterization of Kaolin, Granite, Bentonite, and Barite" 6 (6): 42-53, 2013

21 Svensk Kaernbraenslefoersoerjning AB, "Final Storage of Spent Fuel – KBS-3" Swedish Nuclear Fuel and Waste Management Company 1983

22 D. Meyer, "Evaluation of Clays and Clay Minerals for Application to Repository Sealing" Office of Nuclear Waste Isolation 1983

23 H. Tetsuka, "Effects of Humidity and Interlayer Cations on the Frictional Strength of Montmorillonite" 70 : 56-, 2018

24 M.W. Munthali, "Cs+ and Sr2+ Adsorption Selectivity of Zeolites in Relation to Radioactive Decontamination" 3 (3): 245-250, 2015

25 J. Lee, "Concept of a Korean Reference Disposal System for Spent Fuels" 44 (44): 1565-1573, 2007

26 M. Hayati-Ashtiani, "Characterization of Nano-Porous Bentonite (Montmorillonite) Particles Using FTIR and BET-BJH Analyses" 28 (28): 71-76, 2011

27 W.J. Cho, "Analysis of Functional Criteria for Buffer Material in a Highlevel Radioactive Waste Repository" 31 (31): 116-132, 1999

28 R. Wang, "Adsorption Kinetics of 137Cs+/90Sr2+ on Ca-Bentonite" 89 (89): 791-797, 2017

29 H. Mimura, "Adsorption Behavior of Cesium and Strontium on Synthetic Zeolite P" 30 (30): 436-443, 1993

30 D.A. Dixon, "A Study of the Compaction Properties of Potential Clay-sand Buffer Mixtures for use in Nuclear Fuel Waste Disposal" 21 (21): 247-255, 1985