Our graduating student, Mattia Corti, published the abstract of his initial findings published in the session ‘Application of cutting-edge techniques in global geochemistry: isotopic reservoirs from deep earth, food traceability, and CO2 storage.’ This session will take place on September 21, 2022, in Turin, as part of the joint Congress titled ‘Geosciences for a Sustainable Future‘.
Corti M.*, Maroni P., Barbarossa S., Campione M., Capitani G. & Malaspina N. : Microwave-assisted serpentine reactions with CO2 as a transferrable technology for carbon capture and storage
In the last decades many studies have been focusing on carbon capture and storage to find a possible remedy to reduce the large increase of anthropogenic carbon dioxide. Mineral Carbonation is a potential solution for almost irreversible chemical long-term carbon capture and storage. It concerns the combination of CaO and MgO with CO2 forming spontaneously and exothermically dolomite and magnesite. However, kinetic barriers pose sever limitations for the practical exploitation of this reaction.
High fractions of MgO are available in silicates such as olivine, orthopyroxene, clinopyroxene and
serpentine. To date, data reported that serpentine polymorphs, above all antigorite, is an excellent candidate for fixing the CO2 as the reaction efficiency is approximately 92% compared to lizardite (40%), and olivine (66%).
The microwave assisted process for carbon capture and storage is an innovative technology that can be employed to catalyse the reaction through thermal and non-thermal mechanisms. Some pioneering tests of direct carbonation by microwave hydrothermal equipment have been performed on olivine, lizardite and chrysotile powders (White et al., 2004) but not on antigorite. The structure of serpentine is characterized by stacked layers of SiO2 and brucite, Mg(OH)2. For this reason, mineral carbonation of serpentine involves in principle dissolution of SiO2 layers, dissolution/dehydration of Mg(OH)2 layers, and precipitation of magnesium carbonate.
To address the carbonation reaction mechanism of serpentine, experiments have been performed on model crystalline powders with the aid of a microwave reactor operating at controlled pressure, temperature and environment. Aliquotes of pure brucite, chrysotile, and lizardite, synthesised in our laboratories, were reacted with CO2 under controlled conditions and duration. The characterisation of the structure and morphology of the processed powders was performed by X-Ray Diffraction and by Scanning and Transmission Electron Microscopy.
White W.B., Silsbee M.R. & Kearns B.J. (2004) – Reaction mechanisms of magnesium silicates with carbon dioxide in microwave fields. Pennsylvania State University (US).