University of Oulu

Christophliemk, M. P., Pikkarainen, A. T., Heponiemi, A., Tuomikoski, S., Runtti, H., Hu, T., Kantola, A. M., & Lassi, U. (2022). Preparation and characterization of porous and stable sodium- and potassium-based alkali activated material (Aam). Applied Clay Science, 230, 106697.

Preparation and characterization of porous and stable sodium- and potassium-based alkali activated material (AAM)

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Author: Christophliemk, M.P.1; Pikkarainen, A.T.1; Heponiemi, A.1;
Organizations: 1Research Unit of Sustainable Chemistry, University of Oulu, P.O. Box 4300, FI-90014 Oulu, Finland
2NMR Research Unit, University of Oulu, P.O. Box 3000, FI-90014 Oulu, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 2.9 MB)
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Language: English
Published: Elsevier, 2022
Publish Date: 2022-09-16


The aim of this work is to produce highly porous and stable alkali-activated material (AAM) prepared from two combinations of sodium (Na)- and potassium (K)-based alkali solutions (NaOH/Na₂SiO₃ and KOH/K₂SiO₃). The reactive metakaolin as precursor and AAM were characterized using X-ray diffraction spectroscopy (XRD), X-ray fluorescence spectroscopy (XRF), aluminum nuclear magnetic resonance spectroscopy (27Al MS-NMR), diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), field emission scanning electron microscopy (FESEM), compressive strength measurement and Brunauer–Emmett–Teller (BET) surface analysis. The porosity of the AAMs were increased by using hydrogen peroxide and sodium percarbonate as foaming agents. Characterization results showed the viscosity of the K-AAM paste was 70% lower than that of the Na-AAM paste. However, the volume of the Na-AAM paste in an air-tight plastic tube was three times higher than that of K-AAM, but the specific surface area (SSA) of K-AAM were 30% higher than those of Na-AAM. In terms of compressive strength, the blank AAM (foaming agent-free) demonstrated the highest strength values: 6.1 MPa for K-AAM and 9.0 MPa for Na-AAM. When the concentration of the foaming agent was increased, the compressive strength of both the materials decreased but were still around 1.0 MPa. The FESEM images of the Na-AAM and K-AAM produced with H₂O₂ indicated the high porosity of materials which were also observed in SSA values of AAM. Furthermore, the XRD data showed that the Na-AAM contained water in hydrate form (halloysite) compared with the K-AAM, suggesting the different polymerization reaction route and speed between these AAM.

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Series: Applied clay science
ISSN: 0169-1317
ISSN-E: 1872-9053
ISSN-L: 0169-1317
Volume: 230
Article number: 106697
DOI: 10.1016/j.clay.2022.106697
Type of Publication: A1 Journal article – refereed
Field of Science: 116 Chemical sciences
Funding: This work was financially supported by the Maa- ja vesitekniikan tuki ry, the Erkki Paasikivi Foundation, and the Riitta and Jorma J. Takanen Foundation sr. This study was conducted partly under the auspices of the WaterPro Project (ERDF Project No. A74635 funded by the Central Ostrobothnia Regional Council, European Union, European Regional Development Fund, and Leverage from the EU). The authors have no competing interests to declare that are relevant to the content of this article.
Copyright information: © 2022 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (