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Alkaline attack of boro-alumino-silicate glass : new insights of the molecular mechanism of cold consolidation and new applications

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  • Additional Information
    • Contributors:
      University of St Andrews.EaSTCHEM; University of St Andrews.School of Chemistry
    • Publication Date:
      2025
    • Collection:
      University of St Andrews: Digital Research Repository
    • Abstract:
      Funding: This paper is a part of the dissemination activities of project ‘FunGlass’. This project has received funding from the European Union's Horizon 2020 research and innovation program under grant agreement No 739566. G.T and E.B. acknowledge additional support from the University of Padova (Dept. Industrial Engineering) by means of the project “SusPIRe” (Sustainable porous ceramics from inorganic residues, BIRD202134) and from Italian Ministry of University & Research (MUR), through National project MUR PON R&I 2014–2021 and Next Generation EU funds, PRIN 2022 PNRR project ‘GLASS_TREA.S.U.RES’ (GLASS-based TREAtments for Sustainable Upcycling of inorganic RESidues, #P2022S4TK2). E.B. and S.E.A. acknowledge also the Padua-St Andrews Joint Seed Funding Scheme. ; Alkali activation is of interest for the development of sustainable construction materials, especially those produced from waste-derived reactive alumino-silicate feedstock. Fine powders suspended in concentrated alkaline aqueous solutions undergo gelation during drying by condensation reactions that involve the products of glass dissolution. Boro-alumino-silicate glasses from discarded pharmaceutical containers can be activated under ‘mild’ conditions (2.5 M NaOH/KOH), upon drying at 40 °C for 7 days. This work focuses on the study of specific molecular mechanism of glass hardening after the alkali activation. Contrary to what has been reported for geopolymers, hardening does not result from an extensive dissolution phase. Condensation reactions occur in hydrated surface layers, leading to formation of strong bonds (Si-O-Si, Al-O-Si, etc.) between individual glass particles. Silicates, borates, and aluminates from glass dissolution combine with alkaline ions, yielding additional soluble phases. The proposed mechanism is supported by the results of solid-state NMR spectroscopy and elemental analysis using ICP OES. Stable matrices prepared by direct foaming or by the inclusion of cenospheres or commercial expanded glass (Poraver®) can be ...
    • File Description:
      application/pdf
    • Relation:
      Open Ceramics; 311717928; 85213004207; https://hdl.handle.net/10023/31678
    • Accession Number:
      10.1016/j.oceram.2024.100726
    • Online Access:
      https://hdl.handle.net/10023/31678
      https://doi.org/10.1016/j.oceram.2024.100726
    • Rights:
      © 2024 The Authors. This article is available under the Creative Commons CC-BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/) and permits non-commercial use of the work as published, without adaptation or alteration provided the work is fully attributed.
    • Accession Number:
      edsbas.D6EA9933