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Alteration in molecular structure of alkali activated slag with various water to binder ratios under accelerated carbonation. Sci Rep 2022; 12:5524. [PMID: 35365734 PMCID: PMC8975886 DOI: 10.1038/s41598-022-09491-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 03/24/2022] [Indexed: 11/19/2022] Open
Abstract
Carbonation of alkali activated materials is one of the main deteriorations affecting their durability. However, current understanding of the structural alteration of these materials exposed to an environment inducing carbonation at the nano/micro scale remains limited. This study examined the evolution of phase assemblages of alkali activated slag mortars subjected to accelerated carbonation (1% CO2, 60% relative humidity, up to 28 day carbonation) using XRD, FTIR and 29Si, 27Al, and 23Na MAS NMR. Samples with three water to binder (w/b) ratios (0.35, 0.45, and 0.55) were investigated. The results show that the phase assemblages mainly consisted of C-A-S-H, a disordered remnant aluminosilicate binder, and a minor hydrotalcite as a secondary product. Upon carbonation, calcium carbonate is mainly formed as the vaterite polymorph, while no sodium carbonate is found after carbonation as commonly reported. Sodium acts primarily as a charge balancing ion without producing sodium carbonate as a final carbonation product in the 28-day carbonated materials. The C-A-S-H structure becomes more cross-linked due to the decalcification of this phase as evidenced by the appearance of Q4 groups, which replace the Q1 and Q2 groups as observed in the 29Si MAS NMR spectra, and the dominance of Al(IV) in 27Al MAS NMR. Especially, unlike cementitious materials, the influence of w/b ratio on the crystalline phase formation and structure of C-A-S-H in the alkali activated mortars before and after carbonation is limited.
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Simion A, Vasilescu M, Filip C, Todea M, Mureșan-Pop M, Simon S. Structural characterization of interfaces in silica core-alumina shell microspheres by solid-state NMR spectroscopy. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2022; 117:101773. [PMID: 35051808 DOI: 10.1016/j.ssnmr.2022.101773] [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: 10/12/2021] [Revised: 01/07/2022] [Accepted: 01/07/2022] [Indexed: 06/14/2023]
Abstract
Atomic-scale description of surfaces and interfaces in core-shell aluminosilicate materials is not fully elucidated, partially due to their amorphous character and complex mechanisms that govern their properties. In this paper, new insights into nanostructured core-shell aluminosilicates have been demonstrated, by using different solid-state NMR methods, i.e 29Si, 29Si cross-polarization (CP), 27Al, 27Al triple-quantum (3Q), and 1H-27Al heteronuclear correlation (HETCOR) MAS NMR. For this purpose, nanostructured silica core-alumina shell microspheres, undoped and doped with gadolinium ions respectively, obtained by a chemical synthesis based on the Stöber method for the silica core and electrostatic attraction for developing the alumina shell were studied. As a result, a new alumino-silicate layer formation was proved at the interface between silica core, where aluminum diffuses, on small scale, in the silica network, and alumina shell, where silicon ions migrate, on a larger scale, in the alumina network, leading to a stable core-shell structure. Moreover, this process is accompanied by significant local structural changes in the transition zone, particularly at the aluminum neighborhood, which is quite well understood now, with the power of solid-state NMR spectroscopy.
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Affiliation(s)
- Andrea Simion
- National Center for Magnetic Resonance, Faculty of Physics, Babeș-Bolyai University, 400084, Cluj-Napoca, Romania.
| | - Mihai Vasilescu
- National Center for Magnetic Resonance, Faculty of Physics, Babeș-Bolyai University, 400084, Cluj-Napoca, Romania
| | - Claudiu Filip
- National Institute for Research and Development of Isotopic and Molecular Technologies, 400293, Cluj-Napoca, Romania
| | - Milica Todea
- Institute for Interdisciplinary Research in Bio-Nano-Sciences, Babeș-Bolyai University, 400271, Cluj-Napoca, Romania; Department of Molecular Sciences, Faculty of Medicine, Iuliu Haţieganu University of Medicine and Pharmacy, 400349, Cluj-Napoca, Romania
| | - Marieta Mureșan-Pop
- Institute for Interdisciplinary Research in Bio-Nano-Sciences, Babeș-Bolyai University, 400271, Cluj-Napoca, Romania
| | - Simion Simon
- National Center for Magnetic Resonance, Faculty of Physics, Babeș-Bolyai University, 400084, Cluj-Napoca, Romania; Institute for Interdisciplinary Research in Bio-Nano-Sciences, Babeș-Bolyai University, 400271, Cluj-Napoca, Romania.
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Mili M, Verma S, Hashmi SAR, Gupta RK, Naik A, Rathore SKS, Srivastava AK. Development of advanced bamboo stem derived chemically designed material. JOURNAL OF POLYMER RESEARCH 2021. [DOI: 10.1007/s10965-021-02513-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Liu S, Guan X, Zhang H, Wang Y, Gou M. Revealing the Microstructure Evolution and Carbonation Hardening Mechanism of β-C 2S Pastes by Backscattered Electron Images. MATERIALS 2019; 12:ma12091561. [PMID: 31086018 PMCID: PMC6540250 DOI: 10.3390/ma12091561] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 05/06/2019] [Accepted: 05/08/2019] [Indexed: 11/16/2022]
Abstract
β-dicalcium silicate (β-C2S) minerals were prepared. The compositions, microstructures, and distributions of the carbonation products of hardened β-C2S paste were revealed by X-ray diffraction (XRD), Fourier transform-infrared (FT-IR) spectroscopy, and backscattered electron (BSE) image analysis. The results show that a dense hardened paste of β-C2S can be obtained after 24 h of carbonation curing. The hardened pastes are composed of pores, silica gel, calcium carbonate, and unreacted dicalcium silicate, with relative volume fractions of 1.3%, 42.1%, 44.9%, and 11.7%, respectively. The unreacted dicalcium silicate is encapsulated with a silica gel rim, and the pores between the original dicalcium silicate particles are filled with calcium carbonate. The sufficient carbonation products that rapidly formed during the carbonation curing process, forming a dense microstructure, are responsible for the carbonation hardening of the β-C2S mineral.
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Affiliation(s)
- Songhui Liu
- School of Materials Science and Engineering, Henan Polytechnic University, 2001 Century Avenue, Jiaozuo 454000, China.
| | - Xuemao Guan
- School of Materials Science and Engineering, Henan Polytechnic University, 2001 Century Avenue, Jiaozuo 454000, China.
| | - Haibo Zhang
- School of Materials Science and Engineering, Henan Polytechnic University, 2001 Century Avenue, Jiaozuo 454000, China.
| | - Yuli Wang
- School of Materials Science and Engineering, Henan Polytechnic University, 2001 Century Avenue, Jiaozuo 454000, China.
| | - Mifeng Gou
- School of Materials Science and Engineering, Henan Polytechnic University, 2001 Century Avenue, Jiaozuo 454000, China.
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Seo JH, Amr IT, Park SM, Bamagain RA, Fadhel BA, Kim GM, Hunaidy AS, Lee HK. CO₂ Uptake of Carbonation-Cured Cement Blended with Ground Volcanic Ash. MATERIALS 2018; 11:ma11112187. [PMID: 30400598 PMCID: PMC6267352 DOI: 10.3390/ma11112187] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 10/26/2018] [Accepted: 11/02/2018] [Indexed: 11/19/2022]
Abstract
Accelerated carbonation curing (ACC) as well as partial replacement of cement with natural minerals are examples of many previous approaches, which aimed to produce cementitious products with better properties and environmental amicabilities. In this regard, the present study investigates CO2 uptake of carbonation-cured cement blended with ground Saudi Arabian volcanic ash (VA). Paste samples with cement replacement of 20%, 30%, 40%, and 50% by mass were prepared and carbonation-cured after initial curing of 24 h. A compressive strength test, X-ray diffractometry (XRD), and thermogravimetry were performed. Although pozzolanic reaction of VA hardly occurred, unlike other pozzolana in blended cement, the results revealed that incorporation of VA as a supplementary cementitious material significantly enhanced the compressive strength and diffusion of CO2 in the matrix. This increased the CO2 uptake capacity of cement, reducing the net CO2 emission upon carbonation curing.
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Affiliation(s)
- Joon Ho Seo
- Department of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea.
| | - Issam T Amr
- Carbon Management Division, Research & Development Center, Saudi Aramco, Dhahran 31311, Saudi Arabia.
| | - Sol Moi Park
- Department of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea.
| | - Rami A Bamagain
- Carbon Management Division, Research & Development Center, Saudi Aramco, Dhahran 31311, Saudi Arabia.
| | - Bandar A Fadhel
- Carbon Management Division, Research & Development Center, Saudi Aramco, Dhahran 31311, Saudi Arabia.
| | - Gwang Mok Kim
- Korea Institute of Geoscience and Mineral Resources, Daejeon 34132, Korea.
| | - Ali S Hunaidy
- Carbon Management Division, Research & Development Center, Saudi Aramco, Dhahran 31311, Saudi Arabia.
| | - Haeng Ki Lee
- Department of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea.
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Abstract
The present study investigated geopolymerization in alkali-activated fly ash under elevated pressure conditions. The fly ash was activated using either sodium hydroxide or a combination of sodium silicate solution and sodium hydroxide, and was cured at 120 °C at a pressure of 0.22 MPa for the first 24 h. The pressure-induced evolution of the binder gel in the alkali-activated fly ash was investigated by employing synchrotron X-ray diffraction and solid-state 29Si and 27Al MAS NMR spectroscopy. The results showed that the reactivity of the raw fly ash and the growth of the zeolite crystals were significantly enhanced in the samples activated with sodium hydroxide. In contrast, the effects of the elevated pressure conditions were found to be less apparent in the samples activated with the sodium silicate solution. These results may have important implications for the binder design of geopolymers, since the crystallization of geopolymers relates highly to its long-term properties and functionality.
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Khalid HR, Lee NK, Park SM, Abbas N, Lee HK. Synthesis of geopolymer-supported zeolites via robust one-step method and their adsorption potential. JOURNAL OF HAZARDOUS MATERIALS 2018; 353:522-533. [PMID: 29723813 DOI: 10.1016/j.jhazmat.2018.04.049] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Revised: 04/05/2018] [Accepted: 04/20/2018] [Indexed: 06/08/2023]
Abstract
The present study proposes a robust one-step hydrothermal treatment method for synthesis of high strength geopolymer-supported zeolites utilizing industrial by-products (fly ash and blast furnace slag), which can be potentially used as bulk-type solid adsorbents. The results revealed that the geopolymer-supported zeolites, possessing distinct strengths, zeolite phases (Na-P1, Na-chabazite, and analcime) and pore features depending on the mix design and synthesis conditions, can be easily synthesized employing the proposed one-step method. The geopolymer-supported zeolites exhibited the characteristics of mesoporous materials which are typically desired for commercial adsorbents. The maximum adsorption capacity for Pb2+ was found to be about 37.9 mg/g which is relatively higher than the other bulk-type adsorbents reported for Pb2+ to date. Since industrial by-products are used for synthesis of these materials, it will help in reducing the environmental hazards associated with the permanent disposal of such by-products, with an added advantage that these bulk-type solid adsorbents can be easily retrieved after use unlike granular adsorbents.
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Affiliation(s)
- Hammad R Khalid
- Department of Civil and Environmental Engineering, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, South Korea
| | - N K Lee
- Korea Institute of Civil Engineering and Building Technology, 283 Goyangdae-ro, Ilsanseo-gu, Goyang-si 10223, South Korea
| | - S M Park
- Department of Civil and Environmental Engineering, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, South Korea
| | - N Abbas
- Department of Chemical Engineering, University of Hai'l, Hai'l, Saudi Arabia
| | - H K Lee
- Department of Civil and Environmental Engineering, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, South Korea.
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Rożek P, Król M, Mozgawa W. Spectroscopic studies of fly ash-based geopolymers. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2018; 198:283-289. [PMID: 29558727 DOI: 10.1016/j.saa.2018.03.034] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 03/09/2018] [Accepted: 03/12/2018] [Indexed: 06/08/2023]
Abstract
In the present work fly-ash based geopolymers with different contents of alkali-activator and water were prepared. Alkali-activation was conducted with sodium hydroxide (NaOH) at the SiO2/Na2O molar ratio of 3, 4, and 5. Water content was at the ratio of 30, 40, and 50wt% in respect to the weight of the fly ash. Structural and microstructural characterization (FT-IR spectroscopy, 29Si and 27Al MAS NMR, X-ray diffraction, SEM) of the specimens as well as compressive strength and apparent density measurements were carried out. The obtained geopolymers are mainly amorphous due to the presence of disordered aluminosilicate phases. However, hydroxysodalite have been identified as a crystalline product of geopolymerization. The major band in the mid-infrared spectra (at about 1000cm-1) is related to SiO(Si,Al) asymmetric stretching vibrations and is an indicator of the geopolymeric network formation. Several component bands in this region can be noticed after the decomposition process. Decomposition of band at 1450cm-1 (vibrations of CO bonds in bicarbonate group) has been also conducted. Higher NaOH content favors carbonation, inasmuch as the intensity of the band then increases. Both water and alkaline activator contents have an influence on compressive strength and microstructure of the obtained fly-ash based geopolymers.
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Affiliation(s)
- Piotr Rożek
- AGH University of Science and Technology, Faculty of Materials Science and Ceramics, Al. Mickiewicza 30, 30-059 Krakow, Poland.
| | - Magdalena Król
- AGH University of Science and Technology, Faculty of Materials Science and Ceramics, Al. Mickiewicza 30, 30-059 Krakow, Poland
| | - Włodzimierz Mozgawa
- AGH University of Science and Technology, Faculty of Materials Science and Ceramics, Al. Mickiewicza 30, 30-059 Krakow, Poland
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Property and Microstructure of Waterborne Self-Setting Geopolymer Coating: Optimization Effect of SiO2/Na2O Molar Ratio. MINERALS 2018. [DOI: 10.3390/min8040162] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Park SM, Jang JG, Lee HK. Unlocking the role of MgO in the carbonation of alkali-activated slag cement. Inorg Chem Front 2018. [DOI: 10.1039/c7qi00754j] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
MgO incorporation into alkali-activated slag cement reduces the rate of carbonation.
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Affiliation(s)
- S. M. Park
- Department of Civil and Environmental Engineering
- Korea Advanced Institute of Science and Technology
- Daejeon 34141
- Republic of Korea
| | - J. G. Jang
- Division of Architecture and Urban Design
- Incheon National University
- Incheon
- Republic of Korea
| | - H. K. Lee
- Department of Civil and Environmental Engineering
- Korea Advanced Institute of Science and Technology
- Daejeon 34141
- Republic of Korea
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Park S, Jang J, Son H, Lee H. Stable conversion of metastable hydrates in calcium aluminate cement by early carbonation curing. J CO2 UTIL 2017. [DOI: 10.1016/j.jcou.2017.07.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Cesium and Strontium Retentions Governed by Aluminosilicate Gel in Alkali-Activated Cements. MATERIALS 2017; 10:ma10040447. [PMID: 28772803 PMCID: PMC5506979 DOI: 10.3390/ma10040447] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 04/07/2017] [Accepted: 04/13/2017] [Indexed: 11/16/2022]
Abstract
The present study investigates the retention mechanisms of cesium and strontium for alkali-activated cements. Retention mechanisms such as adsorption and precipitation were examined in light of chemical interactions. Batch adsorption experiments and multi-technical characterizations by using X-ray diffraction, zeta potential measurements, and the N₂ gas adsorption/desorption methods were conducted for this purpose. Strontium was found to crystalize in alkali-activated cements, while no cesium-bearing crystalline phases were detected. The adsorption kinetics of alkali-activated cements having relatively high adsorption capacities were compatible with pseudo-second-order kinetic model, thereby suggesting that it is governed by complex multistep adsorption. The results provide new insight, demonstrating that characteristics of aluminosilicate gel with a highly negatively charged surface and high micropore surface area facilitated more effective immobilization of cesium and strontium in comparison with calcium silicate hydrates.
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Han YK, Jeong G, Lee KJ, Yim T, Kim YJ. A joint experimental and theoretical determination of the structure of discharge products in Na–SO2 batteries. Phys Chem Chem Phys 2016; 18:24841-24844. [DOI: 10.1039/c6cp04423a] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This work is the first to elucidate the governing mechanism of molten-salt batteries by combining experimental and theoretical NMR measurements.
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Affiliation(s)
- Young-Kyu Han
- Department of Energy and Materials Engineering
- Dongguk University-Seoul
- Seoul
- Republic of Korea
| | - Goojin Jeong
- Advanced Batteries Research Center
- Korea Electronics Technology Institute
- Seongnam
- Republic of Korea
| | - Keon-Joon Lee
- Department of Energy and Materials Engineering
- Dongguk University-Seoul
- Seoul
- Republic of Korea
| | - Taeeun Yim
- Department of Chemistry
- Incheon National University
- Incheon
- Republic of Korea
| | - Young-Jun Kim
- Advanced Batteries Research Center
- Korea Electronics Technology Institute
- Seongnam
- Republic of Korea
- SKKU Advanced Institute of Nanotechnology (SAINT)
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