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Istuque DB, Sanches AO, Bortoletto M, Malmonge JA, Soriano L, Borrachero MV, Payá J, Tashima MM, Akasaki JL. Impedance Spectroscopy as a Methodology to Evaluate the Reactivity of Metakaolin Based Geopolymers. MATERIALS (BASEL, SWITZERLAND) 2022; 15:8387. [PMID: 36499884 PMCID: PMC9740586 DOI: 10.3390/ma15238387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 11/18/2022] [Accepted: 11/21/2022] [Indexed: 06/17/2023]
Abstract
The aim of this study was to use the electrical impedance spectroscopy technique (IS) to carry out a systematic study on the mechanism of metakaolin geopolymerization for up to 7 curing days. The study was developed on two batches of metakaolin (MK), and their reaction processes were compared. Interpretative fundamental elements were developed based on the effective electrical conductivity curves regarding the metakaolin geopolymerization. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) were previously carried out and used to interpret and validate the electrical behavior of the fresh and hardened MK-based geopolymer pastes. The results highlighted the sensibility of the impedance technique to the identification and description of the MK geopolymerization process, as well as the changes resulting from even slight variations in the metakaolin composition. Furthermore, this indicated that the geopolymerization process in highly alkaline solutions could be divided into seven stages, including the processes of dissolution, nucleation, precipitation and formation of the gel and, eventually, the retraction/microcracks constitution. Late dissolution processes could be observed during the more advanced stages and were attributed to particles not being fully hydrated.
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Affiliation(s)
- Danilo Bordan Istuque
- MAC—Grupo de Pesquisa em Materiais Alternativos de Construção, Universidade Estadual Paulista (UNESP), Campus de Ilha Solteira, Av. Brasil Sul, 56-Centro, Ilha Solteira 15385-000, SP, Brazil
| | - Alex Otávio Sanches
- MAC—Grupo de Pesquisa em Materiais Alternativos de Construção, Universidade Estadual Paulista (UNESP), Campus de Ilha Solteira, Av. Brasil Sul, 56-Centro, Ilha Solteira 15385-000, SP, Brazil
| | - Marcelo Bortoletto
- MAC—Grupo de Pesquisa em Materiais Alternativos de Construção, Universidade Estadual Paulista (UNESP), Campus de Ilha Solteira, Av. Brasil Sul, 56-Centro, Ilha Solteira 15385-000, SP, Brazil
| | - José Antônio Malmonge
- MAC—Grupo de Pesquisa em Materiais Alternativos de Construção, Universidade Estadual Paulista (UNESP), Campus de Ilha Solteira, Av. Brasil Sul, 56-Centro, Ilha Solteira 15385-000, SP, Brazil
| | - Lourdes Soriano
- Institute of Concrete Science and Technology (ICITECH), Universitat Politècnica de València, 46022 València, Spain
| | - María Victoria Borrachero
- Institute of Concrete Science and Technology (ICITECH), Universitat Politècnica de València, 46022 València, Spain
| | - Jordi Payá
- Institute of Concrete Science and Technology (ICITECH), Universitat Politècnica de València, 46022 València, Spain
| | - Mauro M. Tashima
- MAC—Grupo de Pesquisa em Materiais Alternativos de Construção, Universidade Estadual Paulista (UNESP), Campus de Ilha Solteira, Av. Brasil Sul, 56-Centro, Ilha Solteira 15385-000, SP, Brazil
- Institute of Concrete Science and Technology (ICITECH), Universitat Politècnica de València, 46022 València, Spain
| | - Jorge Luis Akasaki
- MAC—Grupo de Pesquisa em Materiais Alternativos de Construção, Universidade Estadual Paulista (UNESP), Campus de Ilha Solteira, Av. Brasil Sul, 56-Centro, Ilha Solteira 15385-000, SP, Brazil
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Zhang K, Wang K, Liu Z, Ye Z, Zhang B, Lu D, Liu Y, Li L, Xiong Z. Effect of Magnesium Salt (MgCl2 and MgSO4) on the Microstructures and Properties of Ground Granulated Blast Furnace Slag (GGBFS)-Based Geopolymer. MATERIALS 2022; 15:ma15144911. [PMID: 35888384 PMCID: PMC9317973 DOI: 10.3390/ma15144911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 07/11/2022] [Accepted: 07/13/2022] [Indexed: 11/16/2022]
Abstract
The use of seawater to prepare geopolymers has attracted significant research attention; however, the ions in seawater considerably influence the properties of the resulting geopolymers. This study investigated the effects of magnesium salts and alkaline solutions on the microstructure and properties of ground-granulated-blast-furnace-slag-based geopolymers. The magnesium salt–free Na2SiO4-activatied geopolymer exhibited a much higher 28 d compressive strength (63.5 MPa) than the salt-free NaOH-activatied geopolymer (31.4 MPa), with the former mainly containing an amorphous phase (C-(A)-S-H gel) and the latter containing numerous crystals. MgCl2·6H2O addition prolonged the setting times and induced halite and Cl-hydrotalcite formation. Moreover, mercury intrusion porosimetry and scanning electron microscopy revealed that the Na2SiO4-activated geopolymer containing 8.5 wt% MgCl2·6H2O exhibited a higher critical pore size (1624 nm) and consequently, a lower 28 d compressive strength (30.1 MPa) and a more loosely bound geopolymer matrix than the salt-free geopolymer. In contrast, MgSO4 addition had less pronounced effects on the setting time, mineral phase, and morphology. The Na2SiO4-activated geopolymer with 9.0 wt% MgSO4 exhibited a compressive strength of 42.8 MPa, also lower than that of the salt-free geopolymer. The results indicate that Cl− is more harmful to the GGBFS-based geopolymer properties and microstructure than SO42− is.
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Affiliation(s)
- Kun Zhang
- China Construction Third Engineering Bureau Group Co., Ltd., Wuhan 430074, China; (K.Z.); (K.W.); (Z.L.); (Z.Y.)
| | - Kaiqiang Wang
- China Construction Third Engineering Bureau Group Co., Ltd., Wuhan 430074, China; (K.Z.); (K.W.); (Z.L.); (Z.Y.)
| | - Zhimao Liu
- China Construction Third Engineering Bureau Group Co., Ltd., Wuhan 430074, China; (K.Z.); (K.W.); (Z.L.); (Z.Y.)
| | - Zhiwu Ye
- China Construction Third Engineering Bureau Group Co., Ltd., Wuhan 430074, China; (K.Z.); (K.W.); (Z.L.); (Z.Y.)
| | - Baifa Zhang
- School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou 510006, China; (Y.L.); (L.L.); (Z.X.)
- Correspondence: (B.Z.); (D.L.)
| | - Deng Lu
- China Construction Third Engineering Bureau Group Co., Ltd., Wuhan 430074, China; (K.Z.); (K.W.); (Z.L.); (Z.Y.)
- Correspondence: (B.Z.); (D.L.)
| | - Yi Liu
- School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou 510006, China; (Y.L.); (L.L.); (Z.X.)
| | - Lijuan Li
- School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou 510006, China; (Y.L.); (L.L.); (Z.X.)
| | - Zhe Xiong
- School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou 510006, China; (Y.L.); (L.L.); (Z.X.)
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Tian Q, Pan Y, Bai Y, Sasaki K. Immobilization of strontium in geopolymers activated by different concentrations of sodium silicate solutions. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:24298-24308. [PMID: 34822074 DOI: 10.1007/s11356-021-17553-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 11/11/2021] [Indexed: 06/13/2023]
Abstract
Sodium silicate is always used as an activator for the synthesis of geopolymer. However, the effect of sodium silicate concentration on the geopolymer used as adsorbent was still unclear. Therefore, the immobilization of Sr2+ in geopolymers activated by different concentrations of sodium silicate was studied through kinetic and isotherm modeling and solid characterizations including XRD, FTIR, TG, SEM-EDS, and N2 adsorption-desorption isotherm. The adsorption amount of Sr2+ decreased with the sequence of S1, S2, and S3. According to the kinetic and isotherm modeling results, these sorption processes fitted better with pseudo-second-order, mainly governed by film diffusion. However, the diffusion mode was gradually closed to particle diffusion as for the sequence of S3, S2, and S1. Besides, the Langmuir model can be more befitting to sorption data than the Freundlich model, and the free energies decreased with the order of S1, S2, and S3. In addition, the specific surface areas did not change regularly with S1, S2, and S3. Thus, the distribution of Al tetrahedrons has a decisive role in the sorption process of Sr2+, even though the specific surface area is also a critical factor. More Al tetrahedrons can be formed under the activation of sodium silicate with higher concentration, leading to the low Si/Al molar ratio of the as-synthesized geopolymer.
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Affiliation(s)
- Quanzhi Tian
- National Engineering Research Center of Coal Preparation and Purification, China University of Mining and Technology, Xuzhou, 221116, China.
- Department of Earth Resources Engineering, Kyushu University, Fukuoka, 819-0395, Japan.
| | - Yinhai Pan
- National Engineering Research Center of Coal Preparation and Purification, China University of Mining and Technology, Xuzhou, 221116, China
- School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou, 221116, China
| | - Yingchu Bai
- National Engineering Research Center of Coal Preparation and Purification, China University of Mining and Technology, Xuzhou, 221116, China
- School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou, 221116, China
| | - Keiko Sasaki
- Department of Earth Resources Engineering, Kyushu University, Fukuoka, 819-0395, Japan.
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Palomo A, Maltseva O, Garcia-Lodeiro I, Fernández-Jiménez A. Portland Versus Alkaline Cement: Continuity or Clean Break: "A Key Decision for Global Sustainability". Front Chem 2021; 9:705475. [PMID: 34712645 PMCID: PMC8547590 DOI: 10.3389/fchem.2021.705475] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 07/30/2021] [Indexed: 11/21/2022] Open
Abstract
This review undertakes rigorous analysis of much of the copious literature available to the scientific community on the use of alkali-activated binders (AABs) in construction. The authors’ main intention is to categorically refute arguments of that part of the scientific community underestimating or even dismissing the actual potential of AABs as alternatives to Portland cement (PC). The main premise invoked in support of those arguments is a presumed lack of material resources for precursors that would make AAB industrial-scale production unfeasible anywhere on the planet (a substantial number of scientific papers show that the raw materials required for AAB manufacture are in abundance worldwide). The review also analyses the role of alkaline activators in the chemistry of AABs; it is important to clarify and highlight that alkaline activators are not, by any means, confined to the two synthetic products (caustic soda and waterglass) mostly employed by researchers; other sustainable and efficient products are widely available. Finally, the review deals with the versatility of AAB production processes. The technologies required for the large scale manufacturing of AABs are mostly already in place in PC factories; actually no huge investment is required to transform a PC plant in a AAB factory; and quality and compositional uniformity of Alkaline Cements (binders produced through an industrial process) would be guaranteed. The last conclusions extracted from this review-paper are related with: i) the low carbon footprint of one-part AABs and ii) the urgent need of exploring standardization formulas allowing the commercial development of (sustainable) binders different from PC.
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Affiliation(s)
- A Palomo
- Eduardo Torroja Institute for Construction Science, IETcc-CSIC, Madrid, Spain
| | - O Maltseva
- Eduardo Torroja Institute for Construction Science, IETcc-CSIC, Madrid, Spain
| | - I Garcia-Lodeiro
- Eduardo Torroja Institute for Construction Science, IETcc-CSIC, Madrid, Spain
| | - A Fernández-Jiménez
- Eduardo Torroja Institute for Construction Science, IETcc-CSIC, Madrid, Spain
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Ag- or Cu-modified geopolymer filters for water treatment manufactured by 3D printing, direct foaming, or granulation. Sci Rep 2020; 10:7233. [PMID: 32350343 PMCID: PMC7190745 DOI: 10.1038/s41598-020-64228-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 04/14/2020] [Indexed: 11/18/2022] Open
Abstract
In this work, we compared the main characteristics of highly porous geopolymer components for water treatment applications manufactured by 3D printing, direct foaming, or granulation. Furthermore, different approaches to impregnate the materials with Ag or Cu were evaluated to obtain filters with disinfecting or catalytic properties. The results revealed that all of the investigated manufacturing methods enabled the fabrication of components that possessed mesoporosity, suitable mechanical strength, and water permeability, even though their morphologies were completely different. Total porosity and compressive strength values were 28 vol% and 16 MPa for 3D-printed, 70–79 vol% and 1 MPa for direct-foamed, and 27 vol% and 10 MPa for granule samples. Both the filter preparation and the metal impregnation method affected the amount, oxidation state, and stability of Ag and Cu in the filters. However, it was possible to prepare filters with low metal leaching between a pH of 3–7, so that the released Ag and Cu concentrations were within drinking water standards.
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Wei D, Du C, Zhang L, Li Y, Ba L. Preparation of a Composite Calcium Silicate Board with Carbide Slag and Coal-Based Solid Waste Activated by Different Alkali Activators. ACS OMEGA 2020; 5:8934-8942. [PMID: 32337457 PMCID: PMC7178769 DOI: 10.1021/acsomega.0c00709] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Accepted: 03/30/2020] [Indexed: 06/11/2023]
Abstract
Overall performance of composite calcium silicate boards (CCSBs) was investigated to further promote their application. The alkali activators were used to fully hydrate the calcium and silicon raw materials, which further improved the comprehensive performance of the CCSBs made of four pure industrial solid wastes. Within the range of dosage in this study, single doping of different proportions of the alkali activator improved the flexural strength of the CCSB. Based on this, the mechanical properties of the CCSB were further improved as the compounded alkali activator was optimized. Flexural strength is improved when the average pore diameter was refined. The freeze-thaw cycle test shows that a compound-doped alkali activator can effectively reduce the mass loss and strength loss, thereby improving the frost resistance of this material. This research discussed an economically affordable approach to prepare the CCSB material made of industrial solid waste.
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Affiliation(s)
- Dingyi Wei
- School
of Civil and Resources Engineering, University
of Science and Technology Beijing, Xueyuan Road 30, Beijing 100083, China
- State
Key Laboratory of High-Efficient Mining and Safety of Metal Mines
of Ministry of Education, University of
Science and Technology Beijing, Xueyuan Road 30, Beijing 100083, China
| | - Cuifeng Du
- School
of Civil and Resources Engineering, University
of Science and Technology Beijing, Xueyuan Road 30, Beijing 100083, China
- State
Key Laboratory of High-Efficient Mining and Safety of Metal Mines
of Ministry of Education, University of
Science and Technology Beijing, Xueyuan Road 30, Beijing 100083, China
| | - Lianfu Zhang
- School
of Civil and Resources Engineering, University
of Science and Technology Beijing, Xueyuan Road 30, Beijing 100083, China
- Norman
B. Keevil Institute of Mining Engineering, University of British Columbia, Vancouver V6T 1Z4, Canada
| | - Yanxin Li
- Barun
Mining Branch, Inner Mongolia Baotou Steel Union Co., Ltd., by Share
Ltd, Damao Banner, Baotou 014080, China
| | - Lei Ba
- School
of Civil and Resources Engineering, University
of Science and Technology Beijing, Xueyuan Road 30, Beijing 100083, China
- State
Key Laboratory of High-Efficient Mining and Safety of Metal Mines
of Ministry of Education, University of
Science and Technology Beijing, Xueyuan Road 30, Beijing 100083, China
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Contessi S, Calgaro L, Dalconi MC, Bonetto A, Bellotto MP, Ferrari G, Marcomini A, Artioli G. Stabilization of lead contaminated soil with traditional and alternative binders. JOURNAL OF HAZARDOUS MATERIALS 2020; 382:120990. [PMID: 31479822 DOI: 10.1016/j.jhazmat.2019.120990] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 07/27/2019] [Accepted: 08/08/2019] [Indexed: 06/10/2023]
Abstract
The application of an innovative solidification/stabilization (S/S) process was investigated for the remediation of Pb contaminated soil. The performance of Pb stabilization was evaluated by comparing the use of calcium aluminate cement (CAC) and an alkali activated metakaolin binder vs the Ordinary Portland Cement (OPC). The phase composition of the stabilized products was investigated by XRD and correlated to the internal microstructure obtained by SEM-EDX imaging. Leaching tests were performed to ascertain the effectiveness of the proposed binders in the S/S of the contaminated soil, and Pb release was evaluated for each binding system. The overall results proved that multiple mechanisms are involved in Pb retention and that key parameters regulating the stabilization performance are strongly dependent on the type of applied binder system. Pb was found to be associated to C-S-H in the case of OPC, whereas ettringite played a key role in the retention of this contaminant using the CAC binder. The use of a NaOH activated metakaolin resulted in almost total retention of Pb, despite a lack of solidification, highlighting the importance of pH in the regulation of the leaching behavior.
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Affiliation(s)
- Silvia Contessi
- Department of Geosciences, University of Padua, via G. Gradenigo 6, 35129, Padua, Italy.
| | - Loris Calgaro
- Department of Environmental Science, Informatics and Statistics, Ca' Foscari University of Venice, via Torino 155, 30172, Mestre, VE, Italy
| | - Maria Chiara Dalconi
- Department of Geosciences, University of Padua, via G. Gradenigo 6, 35129, Padua, Italy
| | - Alessandro Bonetto
- Department of Environmental Science, Informatics and Statistics, Ca' Foscari University of Venice, via Torino 155, 30172, Mestre, VE, Italy
| | - Maurizio Pietro Bellotto
- Department of Chemistry, Materials and Chemical Engineering, Polytechnic of Milan, piazza Leonardo da Vinci 32, 20133, Milan, Italy
| | | | - Antonio Marcomini
- Department of Environmental Science, Informatics and Statistics, Ca' Foscari University of Venice, via Torino 155, 30172, Mestre, VE, Italy
| | - Gilberto Artioli
- Department of Geosciences, University of Padua, via G. Gradenigo 6, 35129, Padua, Italy
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