Dolomite industrial by-products as active material for CO2 adsorption and catalyst for the acetone condensation

Abstract

The feasibility of using dolomite powders, by-product from the refractory industry, as a CO₂ adsorbent and as a catalyst for the acetone liquid-phase self-condensation is demonstrated in this article. The performance of this material can be largely improved by combining physical pretreatments (hydrothermal ageing, sonication) and thermal activation at different temperatures (500-800 °C). The highest CO₂ adsorption capacity was observed for the sample after sonication and activated at 500 °C (46 mg·g^-1). As to the acetone condensation, the best results were obtained also with the sonicated dolomites, mainly after activation at 800 °C (17.4% of conversion after 5 h at 120 °C). The kinetic model reveals that this material optimizes the equilibrium between catalytic activity (proportional to the total basicity) and deactivation by water (specific adsorption process). These results demonstrate that the valorisation of dolomite fines is feasible, proposing attractive pretreatments for obtaining activated materials with promising results as adsorbents and basic catalysts.