Single-step fabrication of templated Li4SiO4-based pellets for CO2 capture at high temperature

The present study proposes a novel single-step method for the fabrication of macro-porous K2CO3-doped Li4SiO4 pellets for carbon dioxide capture at high temperature and low concentration of CO2. Cylindrical pellets were directly prepared by mechanical compression of precursors and then calcination at high temperature. The pellets characterization evidenced that, during the calcination process, both the synthesis of Li4SiO4 and the develop-ment of macro-porosity into pellets occurred due to the release of decomposition gases. The obtained pellets were tested for CO2 capture at 580 °C and CO2 partial pressure of 0.04 atm, and the long-time stability was evaluated by multiple sorption/desorption cycles operating at moderate Li4SiO4 conversions. This single-step pelletization method allowed to produce a sorbent with high CO2 sorption capacity (253.2 mg CO2/g sorbent) even at low concentration of CO2. Moreover, the single-step pellets displayed a good cyclic stability over 200 adsorption/ desorption cycles, making them suitable for CO2 capture in industrial applications in a fixed bed reactor.