1
|
Kurihara R, Ohkubo T, Maruyama I. Emergence of an Isolated Pore within Calcium-Silicate-Hydrate Gel after Primary Desorption: Detection by 2D 1H NMR T1- T2 Correlation Relaxometry. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2025; 41:9204-9216. [PMID: 40163379 DOI: 10.1021/acs.langmuir.4c03579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/02/2025]
Abstract
Calcium silicate hydrate (C-S-H) is the primary hydration product of modern Portland cement pastes and concrete. Concrete is inevitably dried and rehumidified when it is hardened with water, for operation under ambient conditions. This drying and rehumidification induces a change in the microstructure of the C-S-H agglomerate and is considered the driving factor of anomalous moisture transport in cement pastes. To obtain further insights into the microstructural changes in C-S-H in response to drying/rehumidification, hardened ordinary Portland cement pastes were subjected to a first drying and rehumidification process for >6 months in this study. The relative humidities (RHs) at 20 °C were 23%-75% for first drying and 11%-95% for rehumidification after drying at 105 °C. Two-dimensional 1H NMR T1-T2 relaxation correlation measurements, rather than conventional T2 measurements, were conducted on the conditioned samples. Under sealed conditions, all of the pore-water-related features appeared on the T1-T2 correlation map on a diagonal at a unique T1/T2 ratio. Once the paste was first-dried at RH < 75% or rehumidified at RH < 95%, 1Hs corresponding to water in the interlayer-gel pores appeared on a diagonal with a T1/T2 ratio similar to that of the sealed state, whereas an off-diagonal component was newly identified at T1/T2 > 10 with a T2 value between those of interlayer and gel pores for all the first-dried/rehumidified samples. Although a major change in the water content during drying/rehumidification was observed on the diagonal, the off-diagonal peak likely emanated from the microstructural change in the C-S-H agglomerate upon first drying at RH < 75%. Additionally, the off-diagonal component was consistently observed upon drying/rehumidification, except after the resaturation of the dried paste. Therefore, the appearance of an off-diagonal relaxation component during first drying could be an irreversible feature of the C-S-H microstructural rearrangement.
Collapse
Affiliation(s)
- Ryo Kurihara
- Department of Architecture, Graduate School of Engineering, The University of Tokyo, Tokyo, 113-8656, Japan
| | - Takahiro Ohkubo
- Department of Applied Chemistry and Biotechnology, Graduate School of Engineering, Chiba University, Chiba, 262-8522, Japan
| | - Ippei Maruyama
- Department of Architecture, Graduate School of Engineering, The University of Tokyo, Tokyo, 113-8656, Japan
| |
Collapse
|
2
|
Ding J, Guo S, Han G, Liu Y, Pan Z, Jiang Z, Yan Z, Chen Q, Zhu H. Fully Solar-Powered Uninterrupted Highway Tunnel-Lighting System Enabled by Cement-Based Aqueous Ni-Zn Structural Batteries. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2025; 21:e2412242. [PMID: 40091317 DOI: 10.1002/smll.202412242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2024] [Revised: 02/28/2025] [Indexed: 03/19/2025]
Abstract
Highway tunnel lighting working 24 h a day, 365 days a year largely enables traffic safety but consumes a large amount of electric energy. Moreover, these tunnel lighting installations are powered by lithium-based batteries, which rely on Li sources and flammable organic electrolytes, leading to safety and space issues, or by electric power grids facing geographic limitations and high operating costs. Thus, taking advantage of cement-based materials to create low-cost and high-safety aqueous structural batteries and further develop a self-driven tunnel-lighting system is greatly desirable. Herein, the cement-based aqueous Ni-Zn structural batteries (CNZSBs), solar panels, and LEDs are successfully assembled together to realize a fully solar-powered uninterrupted lighting system, in which the CNZSBs can deliver a maximum energy density of 2.56 kWh m-3, as well as enough compressive strength to act as part of the tunnel structure. Specifically, the solar panels featuring a sustainable energy input can enable the charging of CNZSBs for energy storage and provide stable energy for LEDs during the day, while the fully-charged CNZSBs offer a steady output voltage for lighting at night. Such an uninterrupted lighting system provides exciting opportunities for developing energy storage in building materials and exploiting renewable energy sources.
Collapse
Affiliation(s)
- Jie Ding
- Key Laboratory of Advanced Civil Engineering Materials (Ministry of Education), School of Materials Science and Engineering, Tongji University, Shanghai, 201804, China
| | - Shulai Guo
- Key Laboratory of Advanced Civil Engineering Materials (Ministry of Education), School of Materials Science and Engineering, Tongji University, Shanghai, 201804, China
| | - Guoqi Han
- Key Laboratory of Advanced Civil Engineering Materials (Ministry of Education), School of Materials Science and Engineering, Tongji University, Shanghai, 201804, China
| | - Ying Liu
- SGIDI Engineering Consulting (Group) Co., Ltd, Shanghai, 200093, China
| | - Zhenghui Pan
- Key Laboratory of Advanced Civil Engineering Materials (Ministry of Education), School of Materials Science and Engineering, Tongji University, Shanghai, 201804, China
| | - Zhengwu Jiang
- Key Laboratory of Advanced Civil Engineering Materials (Ministry of Education), School of Materials Science and Engineering, Tongji University, Shanghai, 201804, China
| | - Zhiguo Yan
- State Key Laboratory for Disaster Reduction in Civil Engineering, Tongji University, Shanghai, 200092, China
| | - Qing Chen
- Key Laboratory of Advanced Civil Engineering Materials (Ministry of Education), School of Materials Science and Engineering, Tongji University, Shanghai, 201804, China
- School of Civil Engineering and Architecture, Guangxi University, Nanning, 530004, China
| | - Hehua Zhu
- State Key Laboratory for Disaster Reduction in Civil Engineering, Tongji University, Shanghai, 200092, China
| |
Collapse
|
3
|
Masara F, Benboudjema F, Honorio T. Cavitation, Hydrophilicity, and Sorption Hysteresis in C-S-H Pores: Coupled Effects of Relative Humidity and Temperature. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:27286-27298. [PMID: 39703024 DOI: 10.1021/acs.langmuir.4c03223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2024]
Abstract
Sorption processes are critical for the drying and durability of cement-based materials, directly affecting their thermal properties. Temperature can substantially influence these processes. This work uses molecular simulations to study sorption in C-S-H pores under varying temperatures and relative humidity, considering pore sizes from the gel to the interlayer scale (between 11.6 and 106 Å). We quantify the temperature and pore-size dependence of water cavitation and sorption hysteresis in the C-S-H pores. The critical pore sizes for the disappearance of hysteresis and the reversibility of capillary condensation are identified, with the former being directly associated with cavitation. We show that cavitation occurs only in gel (meso)pores when they are above the critical pore size and below the critical temperature for cavitation. Interlayer pores, a major class of micropores in C-S-H, are not subjected to cavitation. Cavitation in C-S-H pores is homogeneous, occurring in the bulk-like zone of mesopores. The hydrophilicity of the C-S-H surface increases with the temperature, making heterogeneous cavitation less likely to occur. The results above were obtained consistently with three different force field parametrizations, building confidence in their relevance to describe C-S-H interfacial behavior. Finally, we demonstrate that macroscopic considerations for pore emptying and filling, such as the Kelvin-Cohan and equilibrium Derjaguin-Broekhoff-de Boer equations, are not valid or inaccurate when desorption occurs through cavitation in C-S-H. These results are relevant to understanding the sorption processes in other nanolayered adsorbing materials.
Collapse
Affiliation(s)
- Fatima Masara
- Université Paris-Saclay, CentraleSupélec, ENS Paris-Saclay, CNRS, LMPS─Laboratoire de Mécanique Paris-Saclay, 91190 Gif-sur-Yvette, France
| | - Farid Benboudjema
- Université Paris-Saclay, CentraleSupélec, ENS Paris-Saclay, CNRS, LMPS─Laboratoire de Mécanique Paris-Saclay, 91190 Gif-sur-Yvette, France
| | - Tulio Honorio
- Université Paris-Saclay, CentraleSupélec, ENS Paris-Saclay, CNRS, LMPS─Laboratoire de Mécanique Paris-Saclay, 91190 Gif-sur-Yvette, France
| |
Collapse
|
4
|
Hellmann S, Gil-Díaz T, Böhm M, Merten D, Grangeon S, Warmont F, Unbehau S, Sowoidnich T, Schäfer T. Characterization of Nanoparticles in Ethanolic Suspension Using Single Particle Inductively Coupled Plasma Mass Spectrometry: Application for Cementitious Systems. ACS OMEGA 2024; 9:30294-30307. [PMID: 39035945 PMCID: PMC11256340 DOI: 10.1021/acsomega.4c01196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Revised: 04/18/2024] [Accepted: 06/20/2024] [Indexed: 07/23/2024]
Abstract
Single particle inductively coupled plasma mass spectrometry (spICP-MS) is a well-established technique to characterize the size, particle number concentration (PNC), and elemental composition of engineered nanoparticles (NPs) and colloids in aqueous suspensions. However, a method capable of directly analyzing water-sensitive or highly reactive NPs in alcoholic suspension has not been reported yet. Here, we present a novel spICP-MS method for characterizing the main cement hydration product, i.e., calcium-silicate-hydrate (C-S-H) NPs, in ethanolic suspensions, responsible for cement strength. The method viability was tested on a wide range of NP compositions and sizes (i.e., from Au, SiO2, and Fe3O4 NP certified reference materials (CRMs) to synthetic C-S-H phases with known Ca/Si ratios and industrial cement hardening accelerators, X-Seed 100/500). Method validation includes comparisons to nanoparticle tracking analysis (NTA) and transmission/scanning electron microscopy (TEM/SEM). Results show that size distributions from spICP-MS were in good agreement with TEM and NTA for CRMs ≥ 51 nm and the synthetic C-S-H phases. The X-Seed samples showed significant differences in NP sizes depending on the elemental composition, i.e. CaO and SiO2 NPs were bigger than Al2O3 NPs. PNC via spICP-MS was successfully validated with an accuracy of 1 order of magnitude for CRMs and C-S-H phases. The spICP-MS Ca/Si ratios matched known ratios from synthetic C-S-H phases (0.6, 0.8, and 1.0). Overall, our method is applicable for the direct and element-specific quantification of fast nucleation and/or mineral formation processes characterizing NPs (ca. 50-1000 nm) in alcoholic suspensions.
Collapse
Affiliation(s)
- Steffen Hellmann
- Friedrich
Schiller University Jena, Institute of Geosciences,
Applied Geology, Burgweg
11, 07749 Jena, Germany
- International
Max Planck Research School for Global Biogeochemical Cycles, Max Planck Institute for Biogeochemistry, Department
of Biogeochemical Processes, Hans-Knöll-Straße 10, 07745 Jena, Germany
| | - Teba Gil-Díaz
- Friedrich
Schiller University Jena, Institute of Geosciences,
Applied Geology, Burgweg
11, 07749 Jena, Germany
| | - Marcus Böhm
- Friedrich
Schiller University Jena, Institute of Geosciences,
Applied Geology, Burgweg
11, 07749 Jena, Germany
| | - Dirk Merten
- Friedrich
Schiller University Jena, Institute of Geosciences,
Applied Geology, Burgweg
11, 07749 Jena, Germany
| | | | - Fabienne Warmont
- ICMN, 1B, rue de la Férollerie
CS40059, F-45071 Cedex 2 Orléans, France
| | - Sophie Unbehau
- Bauhaus-Universität
Weimar, Institute for Building
Materials, Coudraystr.
11, 99423 Weimar, Germany
| | - Thomas Sowoidnich
- Bauhaus-Universität
Weimar, Institute for Building
Materials, Coudraystr.
11, 99423 Weimar, Germany
| | - Thorsten Schäfer
- Friedrich
Schiller University Jena, Institute of Geosciences,
Applied Geology, Burgweg
11, 07749 Jena, Germany
| |
Collapse
|
5
|
Ruiz-Agudo C, Cölfen H. Exploring the Potential of Nonclassical Crystallization Pathways to Advance Cementitious Materials. Chem Rev 2024; 124:7538-7618. [PMID: 38874016 PMCID: PMC11212030 DOI: 10.1021/acs.chemrev.3c00259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 05/31/2024] [Accepted: 06/03/2024] [Indexed: 06/15/2024]
Abstract
Understanding the crystallization of cement-binding phases, from basic units to macroscopic structures, can enhance cement performance, reduce clinker use, and lower CO2 emissions in the construction sector. This review examines the crystallization pathways of C-S-H (the main phase in PC cement) and other alternative binding phases, particularly as cement formulations evolve toward increasing SCMs and alternative binders as clinker replacements. We adopt a nonclassical crystallization perspective, which recognizes the existence of critical intermediate steps between ions in solution and the final crystalline phases, such as solute ion associates, dense liquid phases, amorphous intermediates, and nanoparticles. These multistep pathways uncover innovative strategies for controlling the crystallization of binding phases through additive use, potentially leading to highly optimized cement matrices. An outstanding example of additive-controlled crystallization in cementitious materials is the synthetically produced mesocrystalline C-S-H, renowned for its remarkable flexural strength. This highly ordered microstructure, which intercalates soft matter between inorganic and brittle C-S-H, was obtained by controlling the assembly of individual C-S-H subunits. While large-scale production of cementitious materials by a bottom-up self-assembly method is not yet feasible, the fundamental insights into the crystallization mechanism of cement binding phases presented here provide a foundation for developing advanced cement-based materials.
Collapse
Affiliation(s)
- Cristina Ruiz-Agudo
- Physical Chemistry, Department of Chemistry, University of Konstanz, Universitätsstr. 10, 78457 Konstanz, Germany
| | - Helmut Cölfen
- Physical Chemistry, Department of Chemistry, University of Konstanz, Universitätsstr. 10, 78457 Konstanz, Germany
| |
Collapse
|
6
|
Liberto T, Nenning A, Bellotto M, Dalconi MC, Dworschak D, Kalchgruber L, Robisson A, Valtiner M, Dziadkowiec J. Detecting Early-Stage Cohesion Due to Calcium Silicate Hydration with Rheology and Surface Force Apparatus. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:14988-15000. [PMID: 36426749 PMCID: PMC9730907 DOI: 10.1021/acs.langmuir.2c02783] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 11/13/2022] [Indexed: 06/16/2023]
Abstract
Extremely robust cohesion triggered by calcium silicate hydrate (C-S-H) precipitation during cement hardening makes concrete one of the most commonly used man-made materials. Here, in this proof-of-concept study, we seek an additional nanoscale understanding of early-stage cohesive forces acting between hydrating model tricalcium silicate (C3S) surfaces by combining rheological and surface force measurements. We first used time-resolved small oscillatory rheology measurements (SAOSs) to characterize the early-stage evolution of the cohesive properties of a C3S paste and a C-S-H gel. SAOS revealed the reactive and viscoelastic nature of C3S pastes, in contrast with the nonreactive but still viscoelastic nature of the C-S-H gel, which proves a temporal variation in the cohesion during microstructural physicochemical rearrangements in the C3S paste. We further prepared thin films of C3S by plasma laser deposition (PLD) and demonstrated that these films are suitable for force measurements in the surface force apparatus (SFA). We measured surface forces acting between two thin C3S films exposed to water and subsequent in situ calcium silicate hydrate precipitation. With the SFA and SFA-coupled interferometric measurements, we resolved that C3S surface reprecipitation in water was associated with both increasing film thickness and progressively stronger adhesion (pull-off force). The lasting adhesion developing between the growing surfaces depended on the applied load, pull-off rate, and time in contact. These properties indicated the viscoelastic character of the soft, gel-like reprecipitated layer, pointing to the formation of C-S-H. Our findings confirm the strong cohesive properties of hydrated calcium silicate surfaces that, based on our preliminary SFA measurements, are attributed to sharp changes in the surface microstructure. In contact with water, the brittle and rough C3S surfaces with little contact area weather into soft, gel-like C-S-H nanoparticles with a much larger surface area available for forming direct contacts between interacting surfaces.
Collapse
Affiliation(s)
- Teresa Liberto
- Institute
of Materials Technology, Building Physics and Construction Ecology,
Faculty of Civil Engineering, Vienna University
of Technology, 1040 Vienna, Austria
| | - Andreas Nenning
- Institute
of Chemical Technologies and Analytics, Vienna Institute of Technology, 1060 Wien, Austria
| | | | - Maria Chiara Dalconi
- Department
of Geoscience and CIRCe Center, University
of Padua, 35131 Padova, Italy
| | - Dominik Dworschak
- Institute
of Applied Physics, Vienna Institute of
Technology, 1040 Wien, Austria
| | - Lukas Kalchgruber
- Institute
of Applied Physics, Vienna Institute of
Technology, 1040 Wien, Austria
| | - Agathe Robisson
- Institute
of Materials Technology, Building Physics and Construction Ecology,
Faculty of Civil Engineering, Vienna University
of Technology, 1040 Vienna, Austria
| | - Markus Valtiner
- Institute
of Applied Physics, Vienna Institute of
Technology, 1040 Wien, Austria
| | - Joanna Dziadkowiec
- Institute
of Applied Physics, Vienna Institute of
Technology, 1040 Wien, Austria
- NJORD Centre,
Department of Physics, University of Oslo, P.O. Box 1048, Oslo 0316, Norway
| |
Collapse
|
7
|
Microstructure and Properties of C–S–H Synthesized in the Presence of Polycarboxylate Superplasticizer. ARABIAN JOURNAL FOR SCIENCE AND ENGINEERING 2022. [DOI: 10.1007/s13369-022-07344-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
|
8
|
Investigation of mechanisms of radiolytic H2 production in C-S-H: Influence of water content and radiation induced defects. Radiat Phys Chem Oxf Engl 1993 2022. [DOI: 10.1016/j.radphyschem.2021.109865] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|
9
|
An Atomistic Model Describing the Structure and Morphology of Cu-Doped C-S-H Hardening Accelerator Nanoparticles. NANOMATERIALS 2022; 12:nano12030342. [PMID: 35159685 PMCID: PMC8839642 DOI: 10.3390/nano12030342] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Revised: 01/13/2022] [Accepted: 01/17/2022] [Indexed: 02/04/2023]
Abstract
Calcium silicate hydrate (C-S-H) is the main binding phase in Portland cement. The addition of C-S-H nanoparticles as nucleation seeds has successfully been used to accelerate the hydration process and the precipitation of binding phases either in conventional Portland cement or in alternative binders. Indeed, the modulation of the hydration kinetics during the early-stage dissolution-precipitation reactions, by acting on the nucleation and growth of binding phases, improves the early strength development. The fine-tuning of concrete properties in terms of compressive strength and durability by designed structural modifications can be achieved through the detailed description of the reaction products at the atomic scale. The nano-sized, chemically complex and structurally disordered nature of these phases hamper their thorough structural characterization. To this aim, we implement a novel multi-scale approach by combining forefront small-angle X-ray scattering (SAXS) and synchrotron wide-angle X-ray total scattering (WAXTS) analyses for the characterization of Cu-doped C-S-H nanoparticles dispersed in a colloidal suspension, used as hardening accelerator. SAXS and WAXTS data were analyzed under a unified modeling approach by developing suitable atomistic models for C-S-H nanoparticles to be used to simulate the experimental X-ray scattering pattern through the Debye scattering equation. The optimization of atomistic models against the experimental pattern, together with complementary information on the structural local order from 29Si solid-state nuclear magnetic resonance and X-ray absorption spectroscopy, provided a comprehensive description of the structure, size and morphology of C-S-H nanoparticles from the atomic to the nanometer scale. C-S-H nanoparticles were modeled as an assembly of layers composed of 7-fold coordinated Ca atoms and decorated by silicate dimers and chains. The structural layers are a few tens of nanometers in length and width, with a crystal structure resembling that of a defective tobermorite, but lacking any ordering between stacking layers.
Collapse
|
10
|
Çevirim-Papaioannou N, Androniuk I, Han S, Mouheb NA, Gaboreau S, Um W, Gaona X, Altmaier M. Sorption of beryllium in cementitious systems relevant for nuclear waste disposal: Quantitative description and mechanistic understanding. CHEMOSPHERE 2021; 282:131094. [PMID: 34470157 DOI: 10.1016/j.chemosphere.2021.131094] [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: 04/19/2021] [Revised: 05/28/2021] [Accepted: 06/01/2021] [Indexed: 06/13/2023]
Abstract
Beryllium has applications in fission and fusion reactors, and it is present in specific streams of radioactive waste. Accordingly, the environmental mobility of beryllium needs to be assessed in the context of repositories for nuclear waste. Although cement is widely used in these facilities, Be(II) uptake by cementitious materials was not previously investigated and was hence assumed negligible. Sorption experiments were performed under Ar-atmosphere. Ordinary Portland cement, low pH cement, calcium silicate hydrated (C-S-H) phases and the model system TiO2 were investigated. Sorption kinetics, sorption isotherms and distribution ratios (Rd, in kg⋅L-1) were determined for these systems. Molecular dynamics were used to characterize the surface processes driving Be(II) uptake. A strong uptake (5 ≤ log Rd ≤ 7) is quantified for all investigated cementitious systems. Linear sorption isotherms are observed over three orders of magnitude in [Be(II)]aq, confirming that the uptake is controlled by sorption processes and that solubility phenomena is not relevant within the investigated conditions. The analogous behaviour observed for cement and C-S-H support that the latter are the main sink of beryllium. The two step sorption kinetics is explained by a fast surface complexation process, followed by the slow incorporation of Be(II) in C-S-H. Molecular dynamics indicate that Be(OH)3- and Be(OH)42- are sorbed to the C-S-H surface through Ca-bridges. This work provides a comprehensive quantitative and mechanistic description of Be(II) uptake by cementitious materials, whose retention properties can be now reliably assessed for a wide range of boundary conditions of relevance in nuclear waste disposal.
Collapse
Affiliation(s)
- N Çevirim-Papaioannou
- Institute for Nuclear Waste Disposal (INE), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany.
| | - I Androniuk
- Institute for Nuclear Waste Disposal (INE), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - S Han
- Division of Advanced Nuclear Engineering (DANE), Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk, South Korea
| | - N Ait Mouheb
- Institute for Nuclear Waste Disposal (INE), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - S Gaboreau
- BRGM Bureau de Recherches Géologiques et Minières, Orleans, France
| | - W Um
- Division of Advanced Nuclear Engineering (DANE), Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk, South Korea
| | - X Gaona
- Institute for Nuclear Waste Disposal (INE), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany.
| | - M Altmaier
- Institute for Nuclear Waste Disposal (INE), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| |
Collapse
|
11
|
Diaz Caselles L, Roosz C, Hot J, Blotevogel S, Cyr M. Immobilization of molybdenum by alternative cementitious binders and synthetic C-S-H: An experimental and numerical study. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 789:148069. [PMID: 34323832 DOI: 10.1016/j.scitotenv.2021.148069] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 05/09/2021] [Accepted: 05/23/2021] [Indexed: 06/13/2023]
Abstract
Excavation operations during construction produce millions of tons of soil sometimes with high leachable molybdenum (Mo) contents, that can lead to risks for both human health and the environment. It is therefore necessary to immobilize the Mo in excavated soils to reduce pollution and lower the costs of soil disposal. This paper studies the immobilization of Mo by three cementitious binders. To this end, one Ordinary Portland cement (OPC), one binder composed of 90% ground granulated blast furnace slag (GGBS) and 10% OPC, and one supersulfated GGBS binder were spiked with sodium molybdate at six different Mo concentrations from 0.005 wt% to 10 wt% before curing. In addition, to gain mechanistic insights, the capacity of synthetic calcium silicate hydrates (C-S-H) to immobilize Mo was studied. This study was completed by thermodynamic modeling to predict the immobilization of Mo at low Mo concentrations (<0.005 wt%). Paste leaching tests results showed that more than 74% of the initial Mo spike was immobilized by the three binders. The supersulfated GGBS binder consistently showed the highest retention levels (92.0 to 99.7%). The precipitation of powellite (CaMoO4) was the dominant mechanism of Mo retention in all binders and most leaching solutions were oversaturated with respect to powellite. Also, in C-S-H syntheses, Mo was largely immobilized (>95%) by the coprecipitation of powellite. Thermodynamic modeling was in good agreement with measured values when the equilibrium constant of powellite was modified to LogK = -7.2. This suggested that powellite is less stable in cementitious environments than would be expected from thermodynamic databases. Moreover, modeling showed that, for a solution at equilibrium with portlandite or C-S-H, the Mo concentration is limited to 1.7 mg/L by powellite precipitation. In contrast, for a solution saturated with respect to ettringite, the threshold concentration for powellite precipitation is 6.5 mg/L.
Collapse
Affiliation(s)
- Laura Diaz Caselles
- LMDC, INSA/UPS Génie Civil, 135 Avenue de Rangueil, 31077 Toulouse cedex 04, France.
| | - Cédric Roosz
- LMDC, INSA/UPS Génie Civil, 135 Avenue de Rangueil, 31077 Toulouse cedex 04, France
| | - Julie Hot
- LMDC, INSA/UPS Génie Civil, 135 Avenue de Rangueil, 31077 Toulouse cedex 04, France
| | - Simon Blotevogel
- LMDC, INSA/UPS Génie Civil, 135 Avenue de Rangueil, 31077 Toulouse cedex 04, France
| | - Martin Cyr
- LMDC, INSA/UPS Génie Civil, 135 Avenue de Rangueil, 31077 Toulouse cedex 04, France
| |
Collapse
|