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Kim B, Kang J, Shin Y, Yeo TM, Heo J, Um W. Effect of Si/Al molar ratio and curing temperatures on the immobilization of radioactive borate waste in metakaolin-based geopolymer waste form. JOURNAL OF HAZARDOUS MATERIALS 2023; 458:131884. [PMID: 37348372 DOI: 10.1016/j.jhazmat.2023.131884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2023] [Revised: 06/14/2023] [Accepted: 06/16/2023] [Indexed: 06/24/2023]
Abstract
Immobilization of radioactive borate waste (RBW) using a geopolymer with a high Si/Al ratio has been challenging because boron-silicon networks lower the compressive strength and delay the setting time. In this study, metakaolin-based geopolymer waste form to immobilize simulant RBW was fabricated using different Si/Al ratios (1.0-1.4) and curing temperatures (26 and 60 ℃). The 7-day compressive strength results revealed that a certain amount of silicon and an elevated curing temperature are required to achieve high compressive strength and waste loading. Following waste acceptance criteria tests, all geopolymers exhibited compressive strengths higher than 3.445 MPa. The leachability index of boron was higher than 6.0, and the leaching mechanism was identified as diffusion. No significant structural changes in the geopolymer were observed after thermal cycling and gamma irradiation tests. The physically bound or unincorporated RBW was leached out of the geopolymer during water immersion and leaching tests; however, boron, which was chemically connected with silicon, was present as an inert phase together with a geopolymer binder. Consequently, immobilizing RBW using a geopolymer with a low Si/Al ratio (1.4) is beneficial in terms of RBW loading and structural durability.
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Affiliation(s)
- Byoungkwan Kim
- Division of Advanced Nuclear Engineering (DANE), Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk 790-784, Republic of Korea
| | - Jaehyuk Kang
- Division of Advanced Nuclear Engineering (DANE), Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk 790-784, Republic of Korea; Department of Electrical and Energy Engineering, Jeju National University, 102, Jejudaehak-ro, Jeju-si, Jeju Special Self-Governing Province, 63243, Republic of Korea
| | - Younglim Shin
- Division of Advanced Nuclear Engineering (DANE), Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk 790-784, Republic of Korea
| | - Tae-Min Yeo
- Graduate Institute of Ferrous & Energy Materials Technology (GIFT), Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk 790-784, Republic of Korea
| | - Jong Heo
- Division of Advanced Nuclear Engineering (DANE), Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk 790-784, Republic of Korea
| | - Wooyong Um
- Division of Advanced Nuclear Engineering (DANE), Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk 790-784, Republic of Korea; Nuclear Environmental Technology Institute (NETI), Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk 790-784, Republic of Korea; Division of Environmental Science and Engineering (DESE), Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk 790-784, Republic of Korea.
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Hamdane H, Oumam M, Mhamdi HS, Bouih A, El Ghailassi T, Boulif R, Alami J, Manoun B, Hannache H. Elaboration of geopolymer package derived from uncalcined phosphate sludge and its solidification performance on nuclear grade resins loaded with 134Cs. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 857:159313. [PMID: 36228800 DOI: 10.1016/j.scitotenv.2022.159313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 09/20/2022] [Accepted: 10/04/2022] [Indexed: 06/16/2023]
Abstract
Nuclear-grade Spent Organic Resin (SOR) contains high concentrations of radioactive nuclides and metal contaminants, while phosphate sludge contains high amount of fine clayey particles and CO32-, both posing a major threat to the biosphere. In this study, a novel geopolymer package (GP) was proposed to directly solidify SOR loaded with 134Cs by incorporating uncalcined phosphate sludge (UPS) as feedstocks, activated by NaOH/KOH. The results showed that alkali-mixed reagents-activated GP is more advantageous in terms of chemical stability and mechanical properties than NaOH-activated GP, recording compressive strength values greater than the waste acceptance criteria and OPC. The 28-day compressive strength of solidified packages can exceed 31 MPa at the highest amount of 42 wt% UPS. The addition of NaF powder into the solidified packages generates more hybrid type gels, which are more conducive to partial dissolution and bonding UPS particles, thereby producing stable and stronger GP. Leaching results of solidified GP in presence of up to 13 wt% SORs showed that only 0.15 % of total 134Cs was leached, even under aggressive solutions. Solidification mechanism revealed that activation of UPS-MK blend forms N,K-A-S-H, (N,K,C)-A-S-H/C-S-H gels coexisting with unreacted particles, thereby solidify/stabilize metal contaminants and Cs+ by a synergetic immobilization action of hydration products via substitution and encapsulation. This study provides a promising paradigm for effective solidification of nuclear-grade resins and synergetic harmless treatment of industrial/phosphate mine solid wastes.
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Affiliation(s)
- Hasna Hamdane
- Laboratory of Engineering and Materials, Faculty of Science Ben M'Sick, Hassan II University of Casablanca, B.P.7955 Casablanca, Morocco; National Center of Sciences, Technology and Nuclear Energy, B.P.1382 Rabat, Morocco.
| | - Mina Oumam
- Laboratory of Engineering and Materials, Faculty of Science Ben M'Sick, Hassan II University of Casablanca, B.P.7955 Casablanca, Morocco
| | - Hicham Si Mhamdi
- Laboratory of Applied Geology, Department of Geosciences, Faculty of Sciences and Techniques Errachidia, Moulay Ismail University of Meknes, Morocco
| | - Abderrahim Bouih
- National Center of Sciences, Technology and Nuclear Energy, B.P.1382 Rabat, Morocco
| | - Touria El Ghailassi
- National Center of Sciences, Technology and Nuclear Energy, B.P.1382 Rabat, Morocco
| | - Rachid Boulif
- Chemical and Biochemical Sciences Department, Mohammed VI Polytechnic University, Lot 660, Hay Moulay Rachid, 43150 Benguerir, Morocco
| | - Jones Alami
- Materials Science and Nano-Engineering Department, Mohammed VI Polytechnic University, Lot 660, Hay Moulay Rachid, 43150 Benguerir, Morocco
| | - Bouchaib Manoun
- Materials Science and Nano-Engineering Department, Mohammed VI Polytechnic University, Lot 660, Hay Moulay Rachid, 43150 Benguerir, Morocco; Univ Hassan(1er), Rayonnement-Matière et Instrumentation, S3M, Faculty of science and Technology, 26000, FST, Settat, Morocco
| | - Hassan Hannache
- Laboratory of Engineering and Materials, Faculty of Science Ben M'Sick, Hassan II University of Casablanca, B.P.7955 Casablanca, Morocco; Materials Science and Nano-Engineering Department, Mohammed VI Polytechnic University, Lot 660, Hay Moulay Rachid, 43150 Benguerir, Morocco
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Asmussen RM, Turner J, Chong S, Riley BJ. Review of recent developments in iodine wasteform production. Front Chem 2022; 10:1043653. [PMID: 36618856 PMCID: PMC9816813 DOI: 10.3389/fchem.2022.1043653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Accepted: 12/05/2022] [Indexed: 12/24/2022] Open
Abstract
Radioiodine capture and immobilization is not only important to consider during the operation of reactors (i.e., I-131), during nuclear accidents (i.e., I-131 and I-129) or nuclear fuel reprocessing (i.e., I-131 and I-129), but also during disposal of nuclear wastes (i.e., I-129). Most disposal plans for I-129-containing waste forms (including spent nuclear fuel) propose to store them in underground repositories. Here, iodine can be highly mobile and, given its radiotoxicity, needs to be carefully managed to minimize long-term environmental impacts arising from disposal. Typically, any process that has been used to capture iodine from reprocessing or in a reactor is not suitable for direct disposal, rather conversion into a wasteform for disposal is required. The objectives of these materials are to use either chemical immobilization or physical encapsulation to reduce the leaching of iodine by groundwaters. Some of the more recent ideas have been to design capture materials that better align with disposal concepts, making the industrial processing requirements easier. Research on iodine capture materials and wasteforms has been extensive. This review will act as both an update on the state of the research since the last time it was comprehensively summarized, and an evaluation of the industrial techniques required to create the proposed iodine wasteforms in terms of resulting material chemistry and applicability.
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Affiliation(s)
- R. Matthew Asmussen
- Pacific Northwest National Laboratory, Richland, WA, United States,*Correspondence: R. Matthew Asmussen, ; Joshua Turner,
| | - Joshua Turner
- National Nuclear Laboratory, Sellafield, Cumbria, United Kingdom,*Correspondence: R. Matthew Asmussen, ; Joshua Turner,
| | - Saehwa Chong
- Pacific Northwest National Laboratory, Richland, WA, United States
| | - Brian J. Riley
- Pacific Northwest National Laboratory, Richland, WA, United States
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Evaluation of Utility of the Cement Solidification Process of Waste Ion Exchange Resin. TOXICS 2022; 10:toxics10030120. [PMID: 35324745 PMCID: PMC8951482 DOI: 10.3390/toxics10030120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 02/22/2022] [Accepted: 02/24/2022] [Indexed: 12/10/2022]
Abstract
The present study aimed to evaluate the utility of the cement solidification process for stably disposing of waste ion exchange resin generated during the treatment of radioactive wastewater. The cement solidification process using the in-drum mixing system was selected to be used for the solidification process of waste ion exchange resins. The disposal safety of waste forms was evaluated according to the waste acceptance criteria (WAC) applicable to domestic waste disposal sites, and the tests were conducted for six test items provided in the WAC. A total of 15 representative samples were collected from the waste-form drums produced using the optimum operating conditions, and their structural stability for disposal considerations was evaluated. In addition, the leaching index of the samples was 11.05, 10.12, 8.39 for Co, Sr, and Cs, respectively, and it was found to exceed 6, the leaching index standard of WAC. The results confirmed that cement waste forms including waste ion exchange resins produced through this process were considered to be conforming to the requirements for disposal safety.
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Abstract
Nano-zeolite is an innovative class of materials that received recognition for its potential use in water and tertiary wastewater treatment. These applications include ion-exchange/sorption, photo-degradation, and membrane separation. The aim of this work is to summarize and analyze the current knowledge about the utilization of nano-zeolite in these applications, identify the gaps in this field, and highlight the challenges that face the wide scale applications of these materials. Within this context, an introduction to water quality, water and wastewater treatment, utilization of zeolite in contaminant removal from water was addressed and linked to its structure and the advances in zeolite preparation techniques were overviewed. To have insights into the trends of the scientific interest in this field, an in-depth analysis of the variation in annual research distribution over the last decade was performed for each application. This analysis covered the research that addressed the potential use of both zeolites and nano-zeolites. For each application, the characterization, experimental testing schemes, and theoretical analysis methodologies were overviewed. The results of the most advanced research were collected, summarized, and analyzed to allow an easy visualization and comparison of these research results. Finally, the gaps and challenges that face these applications are concluded.
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