Chemically Active Silica Aerogel−Wollastonite Composites for CO2 Fixation by Carbonation Reactions

Carbonation reaction from the dissolution of minerals, mainly silicates, is an option for long-term storage of CO2, offering capacity exceeding that of other strategies, and certain advantages such as the formation of insoluble and inert products. This study presents the results of carbonation reactions utilizing silica aerogel wollastonite composites. The procedure for synthesis of the precursor powders with wollastonite stoicheiometry, as well as the compositional and textural features of the resulting composites, was examined first. The kinetic and efficiency of carbonation reactions in aerogel-wollastonite composites were also determined. X-ray diffraction quantitative analysis and thermogravimetric analysis were used to determine the proportions in percent of the resulting carbonate phases. The conversion reaction reaches values above 81% in composites with CaO content of up to 40% by weight, after 40 min of reaction time. The conclusion is that these aerogels, offering a very high specific surface area, are attractive potential materials for CO 2 sequestration and as a supporting material for fast carbonation reactions.