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Towards a clean environment: The potential application of eco-friendly magnesia-silicate cement in CO2 sequestration

Abdel-Gawwad, Hamdy A., Hassan, Hassan Soltan, Vásquez-García, S.R., Israde-Alcántara, Isabel, Ding, Yung-Chin, Martinez-Cinco, Marco Antonio, Abd El-Aleem, S., Khater, Hesham M., Tawfik, Taher A., El-Kattan, Ibrahim M.
Journal of cleaner production 2020 v.252 pp. 119875
X-ray diffraction, ambient temperature, carbon dioxide, carbon sequestration, cement, compression strength, global warming potential, magnesium hydroxide, magnesium oxide, mechanical properties, minerals, thermogravimetry, volcanic ash
The key point of this study is the fabrication of magnesia-based cement with promising mechanical properties and high efficiency of CO₂-capture. The naturally occurring volcanic ashes (white & red ashes) and reactive magnesium oxide are the main materials used in the synthesis of eco-friendly CO₂-capture materials. Volcanic ashes were individually mixed with reactive magnesium oxide at ash to magnesium oxide ratio of 25:75 wt %. The dry blends can react with water to yield hardened materials (at ambient temperature) with compressive strength depends on the type of volcanic ash. A considerable change in the features of the hardened samples was recorded when the fabricated materials exposed to 100% CO₂ gas for 28-days. This change is mainly due to CO₂-capture by magnesium hydroxide Mg(OH)₂ within the fabricated materials, resulting in the formation of Nesquehonite minerals MgCO₃.3H₂O as proved by X-ray diffraction, thermo-gravimetric, and infra-red instrumental techniques. The thermo-gravimetric analysis demonstrates that, the fabricated sample containing low amorphous red ashes has higher CO₂-capture capacity (∼260 kg/ton) compared to that having high amorphous white volcanic ashes (∼220 kg/ton) at 28-days of CO₂-exposure. Accordingly, the fabricated magnesia-based cement is not only used as cementitious material with outstanding mechanical properties, but also used as a super CO₂-absorbent precursor. This can strongly contribute in the mitigation of global warming potential caused by different industrial activities.