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Sharma R, Das KK, Siddique S, Jang JG. Cesium immobilization of high pH and low pH belite-rich cement under varying temperature. JOURNAL OF HAZARDOUS MATERIALS 2024; 469:133995. [PMID: 38492390 DOI: 10.1016/j.jhazmat.2024.133995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 01/29/2024] [Accepted: 03/07/2024] [Indexed: 03/18/2024]
Abstract
Low-pH cement is being studied in radioactive waste repositories. The belite-rich cement (BRC) recently gained attention due to its higher CO2 sequestration and low pH attainment under carbonation exposure. Therefore, this study evaluated the effects of pH and temperature on cesium immobilization of BRC. High pH (12.6) and low pH (9.9) BRC were produced via air curing and carbonation treatment, respectively. The high and low pH BRC samples were placed in a leaching environment at 25 °C and 45 °C for 90 days. An inverse correlation between pH and cesium mobilization of BRC was observed. The high pH BRC achieved the lowest effective diffusion coefficient (4.05E-09 cm2/s), whereas the highest value (2.64E-07 cm2/s) was achieved in case of low pH BRC. The physicochemical and morphological properties unveiled the decrease in Si/Ca ratio of gel, precipitation of Ca2+ ions in calcite formation, and increment in pore structure connectivity (pore size > 100 nm) in low pH BRC. However, the high pH BRC demonstrated the high Si/Ca ratio in C-S-H gel, hydroxide phases and higher disconnected pores. Thermodynamic modeling revealed the presence of significant carbonated phases beyond 15% CO2 uptake. The findings contributed to the BRC's feasibility in developing nuclear waste storage facility.
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Affiliation(s)
- Raju Sharma
- Division of Architecture and Urban Design, Urban Science Institute, Incheon National University, 119 Academy-ro, Yeonsu-gu, Incheon 22012, Republic of Korea
| | - Kunal Krishna Das
- Division of Architecture and Urban Design, Urban Science Institute, Incheon National University, 119 Academy-ro, Yeonsu-gu, Incheon 22012, Republic of Korea
| | - Salman Siddique
- Interdisciplinary Research Center for Construction and Building Materials, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia
| | - Jeong Gook Jang
- Division of Architecture and Urban Design, Urban Science Institute, Incheon National University, 119 Academy-ro, Yeonsu-gu, Incheon 22012, Republic of Korea.
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2
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Goo JY, Choi S, Kim BJ, Jeong J, Kwon JS, Jo HY. Effects of EDTA on the leaching behaviors of Cs(I) and Co(II) from cement waste forms. JOURNAL OF HAZARDOUS MATERIALS 2024; 463:132830. [PMID: 37944230 DOI: 10.1016/j.jhazmat.2023.132830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2023] [Revised: 10/09/2023] [Accepted: 10/20/2023] [Indexed: 11/12/2023]
Abstract
Cementation is extensively employed for immobilizing radionuclides in low- and intermediate-level radioactive wastes generated during the decommissioning of nuclear power plants. Ethylenediaminetetraacetic acid (EDTA), used as a decontamination agent during the decommissioning process, can be introduced into the cement waste form containing radionuclides. This study investigated the effects of the EDTA present in simulated radioactive decommissioning wastes on the leaching behaviors of Co and Cs immobilized in the cement waste form. Co leaching was facilitated by the formation of highly mobile Co-EDTA complexes. However, Cs leaching was impeded by the competition for leaching with other metal-EDTA complexes. Moreover, the EDTA-induced carbonated layer with a dense pore structure played a crucial role as a retardation barrier for the Cs leaching. The calcite contents of the samples with 8 wt% EDTA were approximately three times higher than those of the samples without EDTA. The introduced EDTA affected the leaching behaviors of both Co and Cs, as well as the microstructure evolution of the cement waste form. Nevertheless, the addition of EDTA had a relatively low positive effect on the efficiency of Cs immobilization, but also an obvious negative effect on the efficiency of Co immobilization, regardless of the concentration of EDTA. Finally, an EDTA dosage of 1 wt% in the cement waste forms containing Co or Cs is suggested as a potential waste acceptance criterion for solidified low- and intermediate-level radioactive waste.
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Affiliation(s)
- Ja-Young Goo
- Korea Atomic Energy Research Institute, 989, Daedeok-daero, Yuseong-gu, Daejeon 34057, Republic of Korea; Department of Earth and Environmental Sciences, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
| | - Seonggyu Choi
- Korea Atomic Energy Research Institute, 989, Daedeok-daero, Yuseong-gu, Daejeon 34057, Republic of Korea
| | - Bong-Ju Kim
- Korea Atomic Energy Research Institute, 989, Daedeok-daero, Yuseong-gu, Daejeon 34057, Republic of Korea
| | - Jongtae Jeong
- Korea Atomic Energy Research Institute, 989, Daedeok-daero, Yuseong-gu, Daejeon 34057, Republic of Korea
| | - Jang-Soon Kwon
- Korea Atomic Energy Research Institute, 989, Daedeok-daero, Yuseong-gu, Daejeon 34057, Republic of Korea.
| | - Ho Young Jo
- Department of Earth and Environmental Sciences, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea.
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Peng G, Zhang P, Zeng L, Yu L, Li D. Immobilization of chromium ore processing residue by alkali-activated composite binders and leaching characteristics. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023:10.1007/s11356-023-27409-z. [PMID: 37162678 DOI: 10.1007/s11356-023-27409-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 04/30/2023] [Indexed: 05/11/2023]
Abstract
Chromium ore processing residue (COPR) is classified as hazardous solid waste because of the leachable Cr(VI). Cementitious materials are often used to solidify and stabilize heavy metals. However, most of them focus on the leaching concentration of particles after solidification and stabilization and lack research on leaching characteristics. This study investigated the leaching characteristics of heavy metals in three simulated environments (HJ557-2010, HJ/T299-2007, TCLP) after immobilizing COPR with composite binders. Industrial solid waste coal fly ash and lead-zinc smelting slag are used to prepare composite binders through alkali activation technology. Compressive strength, particle leaching toxicity, acid neutralization capability, and semi-dynamic leaching test are used to evaluate the performance of the solidified body. The solidified body can be applied to building materials or treated as general industrial waste. Heavy metals are mainly released from the matrix by surface washing at a low rate. The analysis results, including XRD, FTIR, and SEM-EDS, show that chemical binding and physical encapsulation are the main immobilizing mechanisms to realize the coordinated disposal of Zn and Cr(VI).
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Affiliation(s)
- Guangjun Peng
- State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing, 400044, China
- College of Resource and Safety Engineering, Chongqing University, Chongqing, 400044, China
| | - Pengpeng Zhang
- State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing, 400044, China
- College of Resource and Safety Engineering, Chongqing University, Chongqing, 400044, China
| | - Linghao Zeng
- State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing, 400044, China
- College of Resource and Safety Engineering, Chongqing University, Chongqing, 400044, China
| | - Lin Yu
- State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing, 400044, China
- College of Resource and Safety Engineering, Chongqing University, Chongqing, 400044, China
| | - Dongwei Li
- State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing, 400044, China.
- College of Resource and Safety Engineering, Chongqing University, Chongqing, 400044, China.
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Wang F, Zhou M, Chen C, Yuan Z, Geng X, Yang S. Solidification of uranium tailings using alkali-activated slag mixed with natural zeolite. NUCLEAR ENGINEERING AND TECHNOLOGY 2022. [DOI: 10.1016/j.net.2022.10.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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5
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Influence of Fly Ash Denitrification on Properties of Hybrid Alkali-Activated Composites. CRYSTALS 2022. [DOI: 10.3390/cryst12050633] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
This article deals with the possibility of partial replacement of blast furnace slag (GGBFS) with fly ash after denitrification (FAD) in alkali-activated materials. Physical-mechanical and durability properties were tested, hydration reaction was monitored, and infrared spectroscopy was performed. Results were compared between mixtures prepared with fly ash without denitrification (FA), and also with a mixture based only on GGBFS. The basic result is that hybrid alkali-systems with FAD show similar trends to FA. The significant effect of fly ash is manifested in terms of its resistance to freeze-thaw processes. Reactions in a calorimeter show a slower development of reactions with increasing replacement of GGBFS due to the lower reactivity of the fly ash. Through testing the leaching resistance, a decrease in flexural strength was found. This may be due to the descaling of the main hydration product, C–(A)–S–H gel. After 28 days of maturation, compressive strengths of all monitored mixtures ranged from 96 to 102 MPa. The flexural strengths ranged from 6.8 to 8.0 MPa. After 28 days of maturation, the higher strengths reached mixtures without replacing GGBFS. In terms of resistance to freeze-thaw processes, the largest decrease (almost 20%) of flexural strength was achieved by a mixture with 30% of GGBFS replacement by FA. No fundamental differences were found for the mixtures in the FTIR analysis.
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Gonçalves MFS, Petraconi Filho G, Couto AA, Silva Sobrinho ASD, Miranda FS, Massi M. Evaluation of thermal plasma process for treatment disposal of solid radioactive waste. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2022; 311:114895. [PMID: 35299134 DOI: 10.1016/j.jenvman.2022.114895] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Revised: 03/08/2022] [Accepted: 03/11/2022] [Indexed: 06/14/2023]
Abstract
The management of radioactive waste is a worldwide activity based on the guidelines of the International Atomic Energy Agency (IAEA), and all stages of management require scientifically proven methods for possible deployment. The management of radioactive waste is a huge challenge due to the high risk in the collection, gathering, transport, handling, and storage. In this study, a thermal plasma treatment process was evaluated for its efficiency to process solid radioactive waste. Experiments were carried out with the application of stable isotopes of Lead, Iodine, Cobalt, and Cesium. After the thermal plasma treatments, the slag and the residual gas were analyzed to verify the influence of process time and discharge power on the efficiency of the process. The treatment for 25 min and 10 kW was sufficient to reduce the mass by 50% of the slag. When the applied power was increased to 15 kW, an expressive reduction in the treatment time (10 min) was able to promote the same mass reduction. The results indicated that the treatment of radioactive waste by thermal plasma is a promising method to manage and reduce the mass and volume for the final disposal.
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Affiliation(s)
- M F S Gonçalves
- Mackenzie Presbyterian University, School of Engineering - PPGEMN, 01302-907, São Paulo, SP, Brazil.
| | - G Petraconi Filho
- Technological Institute of Aeronautics, ITA/DCTA, 12227-000, São Jose dos Campos, São Paulo, Brazil
| | - A A Couto
- Mackenzie Presbyterian University, School of Engineering - PPGEMN, 01302-907, São Paulo, SP, Brazil
| | - A S da Silva Sobrinho
- Technological Institute of Aeronautics, ITA/DCTA, 12227-000, São Jose dos Campos, São Paulo, Brazil
| | - F S Miranda
- Technological Institute of Aeronautics, ITA/DCTA, 12227-000, São Jose dos Campos, São Paulo, Brazil
| | - M Massi
- Mackenzie Presbyterian University, School of Engineering - PPGEMN, 01302-907, São Paulo, SP, Brazil
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Zeng Q, Pang X, Li K. Kinetics of low radioactive wastewater imbibition and radionuclides sorption in partially saturated ternary-binder mortar. JOURNAL OF HAZARDOUS MATERIALS 2022; 422:126897. [PMID: 34419840 DOI: 10.1016/j.jhazmat.2021.126897] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 08/09/2021] [Accepted: 08/10/2021] [Indexed: 06/13/2023]
Abstract
This study seeks to assess the imbibition kinetics of low radioactive wastewater (from the DayaBay nuclear power plant) into a partially saturated ternary-binder mortar, as well as the sorption kinetics of 60Co and 137Cs from the water. Mortar samples with the initial saturation degrees of 0, 0.4, 0.6, 0.8 and 1.0 were prepared for the wastewater treatment. Pore structure of the mortar was characterized using water vapor sorption isotherm and mercury intrusion porosimetry tests interpreted by the Guggenheim-Anderson-de Boer isothermal equilibrium, and volume- and energy-based fractal models. Results show that the mortar has consistent fractal pore structure between the models, and the liquid imbibitions follow the fractal imbibition kinetics, in which the parameters are non-linearly impacted by the initial saturation degrees. The sorption rate and retention capacity of 137Cs are much lower than those of 60Co, and both follow the Brouers-Sotolongo fractional kinetics. The findings uncover the complex liquid imbibition and radionuclides sorption kinetics in cement-based porous materials, and the in-situ data would contribute to the material designs and sorption controls for large scale in-situ treatments of wastewater from nuclear power plant.
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Affiliation(s)
- Qiang Zeng
- Department of Civil Engineering, Tsinghua University, 100084 Beijing, PR China; College of Civil and Architecture Engineering, Zhejiang University, Hangzhou 310058, PR China.
| | - Xiaoyun Pang
- Department of Civil Engineering, Tsinghua University, 100084 Beijing, PR China
| | - Kefei Li
- Department of Civil Engineering, Tsinghua University, 100084 Beijing, PR China.
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8
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Li J, Chen L, Wang J. Solidification of radioactive wastes by cement-based materials. PROGRESS IN NUCLEAR ENERGY 2021. [DOI: 10.1016/j.pnucene.2021.103957] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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9
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Luo Y, He D. Research status and future challenge for CO 2 sequestration by mineral carbonation strategy using iron and steel slag. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:49383-49409. [PMID: 34331652 DOI: 10.1007/s11356-021-15254-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Accepted: 06/28/2021] [Indexed: 06/13/2023]
Abstract
Mineral carbonation can simultaneously realize the effective treatment of CO2 and iron and steel slag; thus, it is of great significance for the low carbon and sustainable development of iron and steel industry. In this article, the researches of mineral carbonation process using iron and steel slag as feedstock are reviewed, and the carbonation reaction mechanism and the parameters affecting the reaction rate and carbonation degree are analyzed. Furthermore, the effect of different enforcement approaches, such as ultrasonic enhancement, mixed calcination, microbial enhancement, and cyclic coprocessing on mineral carbonation reaction, is introduced. The additional effects of mineral carbonation, such as solving the problem of poor volume stability of steel slag, weakening the leaching of heavy metal ions, and reducing the pH of the leachate, are also illustrated. Moreover, issues related to mineral carbonation technology that should be emphasized upon soon, such as the production of valuable products, use of industrial wastewater, aqueous phase recycling use, multiparameter coupling analysis, and research on the properties of carbonation residues, are also discussed, which contribute some perspectives to the future development of mineral carbonation of iron and steel slag.
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Affiliation(s)
- Yinbo Luo
- Department of Ferrous Metallurgy, School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Dongfeng He
- Department of Ferrous Metallurgy, School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing, 100083, China.
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10
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Li J, Xu D, Wang X, Liu K, Mao Y, Wang M, Bai Y, Wang W. Encapsulation of cesium with a solid waste-derived sulfoaluminate matrix: A circular economy approach of treating nuclear wastes with solid wastes. JOURNAL OF HAZARDOUS MATERIALS 2021; 416:126156. [PMID: 34492936 DOI: 10.1016/j.jhazmat.2021.126156] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Revised: 05/03/2021] [Accepted: 05/14/2021] [Indexed: 06/13/2023]
Abstract
It is of great importance to safely dispose nuclear wastes with the development of nuclear industries. Past approaches to this problem have included immobilizing radioactive cesium in Portland cement-based matrices; however, the leaching rates of cesium are relatively high, especially as the leaching temperature increases. This paper explores a high-efficiency and cost-effective approach for encapsulating cesium using a sulfoaluminate cement (SAC) matrix, which was prepared via synergetic use of industrial solid wastes. Leaching results showed that, the apparent diffusion coefficient values of cesium were only ~1.4 × 10-15 cm2/s and ~5 × 10-18 cm2/s at 25 ℃ and 90 ℃ leaching conditions, respectively. These values were several orders of magnitude lower when compared with previously reported values, indicating the excellent encapsulation performance of the solid-waste-based SAC for cesium. Moreover, the heavy metals contained in the industrial solid waste were also effectively immobilized. A mechanistic analysis revealed that cesium was encapsulated in the SAC matrices stably by a physical effect. Finally, a life cycle assessment and economic analysis indicated that this approach was environmental-friendly, cost-effective, and energy-saving. This work provides a promising strategy for effective encapsulation of cesium and synergetic treatment of industrial solid wastes.
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Affiliation(s)
- Jingwei Li
- Shandong Engineering Laboratory for Solid Waste Green Materials, National Engineering Laboratory for Reducing Emissions from Coal Combustion, Engineering Research Center of Environmental Thermal Technology of Ministry of Education, Shandong Key Laboratory of Energy Carbon Reduction and Resource Utilization, School of Energy and Power Engineering, Shandong University, Jinan 250014, China
| | - Dong Xu
- Shandong Engineering Laboratory for Solid Waste Green Materials, National Engineering Laboratory for Reducing Emissions from Coal Combustion, Engineering Research Center of Environmental Thermal Technology of Ministry of Education, Shandong Key Laboratory of Energy Carbon Reduction and Resource Utilization, School of Energy and Power Engineering, Shandong University, Jinan 250014, China
| | - Xujiang Wang
- Shandong Engineering Laboratory for Solid Waste Green Materials, National Engineering Laboratory for Reducing Emissions from Coal Combustion, Engineering Research Center of Environmental Thermal Technology of Ministry of Education, Shandong Key Laboratory of Energy Carbon Reduction and Resource Utilization, School of Energy and Power Engineering, Shandong University, Jinan 250014, China
| | - Kang Liu
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Yanpeng Mao
- Shandong Engineering Laboratory for Solid Waste Green Materials, National Engineering Laboratory for Reducing Emissions from Coal Combustion, Engineering Research Center of Environmental Thermal Technology of Ministry of Education, Shandong Key Laboratory of Energy Carbon Reduction and Resource Utilization, School of Energy and Power Engineering, Shandong University, Jinan 250014, China
| | - Mengmeng Wang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Yun Bai
- Department of Civil, Environmental and Geomatic Engineering, University College London, Gower Street, London, WC1E 6BT, UK
| | - Wenlong Wang
- Shandong Engineering Laboratory for Solid Waste Green Materials, National Engineering Laboratory for Reducing Emissions from Coal Combustion, Engineering Research Center of Environmental Thermal Technology of Ministry of Education, Shandong Key Laboratory of Energy Carbon Reduction and Resource Utilization, School of Energy and Power Engineering, Shandong University, Jinan 250014, China.
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11
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He P, Wang Q, Fu S, Wang M, Zhao S, Liu X, Jiang Y, Jia D, Zhou Y. Hydrothermal transformation of geopolymers to bulk zeolite structures for efficient hazardous elements adsorption. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 767:144973. [PMID: 33636773 DOI: 10.1016/j.scitotenv.2021.144973] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 12/19/2020] [Accepted: 01/02/2021] [Indexed: 06/12/2023]
Abstract
This paper reports a facile route to prepare bulk zeolites with tunable phase compositions and microstructures by combining hydrothermal treatment and geopolymer precursor technique. Amorphous Na-based geopolymer (NaGP) is transformed into crystalline analcime following hydrothermal treatments. By systematically investigating the effects of hydrothermal conditions on the phase compositions and microstructures of the products, the optimal hydrothermal procedure is screened as treating NaGP in 1 M NaOH solution at 160 °C for 6 h. Furthermore, we achieve control over phase compositions of the resulting bulk zeolites by tailoring the initial Na/K ratio of geopolymer precursors. For instance, treating the geopolymer precursor with a Na/K ratio of 9: 1 under the optimal hydrothermal procedure leads to the formation of zeolite consisting of analcime and zeolite-P. The as-prepared adsorbents exhibit outstanding adsorption performance for the hazardous elements, among which analcime-zeolite-P shows an adsorption efficiency of 93.3% for Cs+, and NaGP exhibits an adsorption efficiency of 99.6% for Sr2+. Moreover, we reveal the mechanisms underlying the adsorption of Cs+ and Sr2+ in the adsorbents to be chemisorption. Meanwhile, ion exchanges also occur in NaGP and analcime-zeolite-P during Cs+ adsorption. These results render geopolymers and their derived bulk zeolites promising for hazardous elements adsorption.
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Affiliation(s)
- Peigang He
- Institute for Advanced Ceramics, School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, PR China; Key Laboratory of Advanced Structural-Functional Integration Materials & Green Manufacturing Technology, Harbin Institute of Technology, Harbin 150001, PR China.
| | - Qikun Wang
- Institute for Advanced Ceramics, School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, PR China; Key Laboratory of Advanced Structural-Functional Integration Materials & Green Manufacturing Technology, Harbin Institute of Technology, Harbin 150001, PR China
| | - Shuai Fu
- Institute for Advanced Ceramics, School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, PR China; Key Laboratory of Advanced Structural-Functional Integration Materials & Green Manufacturing Technology, Harbin Institute of Technology, Harbin 150001, PR China
| | - Meiling Wang
- Institute for Advanced Ceramics, School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, PR China; Key Laboratory of Advanced Structural-Functional Integration Materials & Green Manufacturing Technology, Harbin Institute of Technology, Harbin 150001, PR China
| | - Shengjian Zhao
- Institute for Advanced Ceramics, School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, PR China; Key Laboratory of Advanced Structural-Functional Integration Materials & Green Manufacturing Technology, Harbin Institute of Technology, Harbin 150001, PR China
| | - Xuzhao Liu
- Department of Materials, The University of Manchester, Sackville Street Building, Manchester M1 3BB, United Kingdom
| | - Yuqi Jiang
- Institute for Advanced Ceramics, School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, PR China; Key Laboratory of Advanced Structural-Functional Integration Materials & Green Manufacturing Technology, Harbin Institute of Technology, Harbin 150001, PR China
| | - Dechang Jia
- Institute for Advanced Ceramics, School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, PR China; Key Laboratory of Advanced Structural-Functional Integration Materials & Green Manufacturing Technology, Harbin Institute of Technology, Harbin 150001, PR China.
| | - Yu Zhou
- Institute for Advanced Ceramics, School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, PR China; Key Laboratory of Advanced Structural-Functional Integration Materials & Green Manufacturing Technology, Harbin Institute of Technology, Harbin 150001, PR China
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Abstract
Alkali-activated materials are an emerging technology that can serve as an alternative solution to ordinary Portland cement. Due to their alkaline nature, these materials are inherently more electrically conductive than ordinary Portland cement, and have therefore seen numerous applications as sensors and self-sensing materials. This review outlines the current state-of-the-art in strain, temperature and moisture sensors that have been developed using alkali activated materials. Sensor fabrication methods, electrical conductivity mechanisms, and comparisons with self-sensing ordinary Portland cements are all outlined to highlight best practice and propose future directions for research.
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13
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Synthesis of Fly Ash-Based Geopolymers: Effect of Calcite Addition and Mechanical Activation. MINERALS 2020. [DOI: 10.3390/min10090827] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Blends of fly ash and natural calcite, mechanically activated for 0–400 s in a planetary mill, were used to synthesize geopolymers at ambient temperature. The calcite content in the blends was 0–10 wt.%. Sodium hydroxide solution was used as an alkaline agent. Mechanical activation of the raw material considerably enhanced its reactivity with respect to the alkaline agent, as was observed using Fourier-transform infrared spectroscopy, isothermal conduction calorimetry, thermogravimetry coupled with mass spectrometry analysis of the evolved gas, and SEM/EDS. The addition of calcite to the fly ash improved the compressive strength of the geopolymers, especially during the early age of curing. For 7 d aged geopolymers based on the 90% fly ash + 10% calcite blend, the strength was 8.0-, 3.5- and 2.9-fold higher than that for the geopolymers based on the unblended fly ash for 30 s, 180 s and 400 s mechanical activation time, respectively. Using Mössbauer spectroscopy, it was revealed that iron present in the fly ash did not play a significant part in the geopolymerization process. The dominant reaction product was sodium containing aluminosilicate hydrogel (N-A-S-H gel). Calcite was found to transform, to a small extent, to vaterite and Ca(OH)2 in the course of the geopolymerization.
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