Enhancing Aqueous Carbonation of Calcium Silicate through Acid and Base Pretreatments with Implications for Efficient Carbon Mineralization

• DOI: 10.1021/acs.est.3c03942
• Publication Date: 2023-09-06T19:42:17Z
• Authors: Hang Zhai; Qiyuan Chen; Mehmet Yilmaz; Bu Wang
• Keywords: Carbonatation

Carbon dioxide (CO2) mineralization based on aqueous carbonation of alkaline earth silicate minerals is a promising route toward large-scale carbon removal. Traditional methods largely adopt acidification-based approaches, e.g., using concentrated/pressurized CO2 or acidic media, to accelerate mineral dissolution and carbonation. In this study, we designed tested three distinctive routes evaluate the effect pretreatments under different pH conditions carbonation, amorphous calcium (CS) as an example system. Pretreating CS with high concentrations (100 mM) HCl (Route I) NaOH II III) enhanced their degrees. However, pretreatment overall yielded higher degrees than pretreatment, highest degree achieved through Route III, where extra step taken after remove solution containing dissolved silica prior The formed intermediate products surface. Silica precipitated from had minimal degree. Ca/Si ratio phases NaOH, other hand, can be readily carbonated. contrast commonly utilized basification offers more it mitigate need for costly swing high-concentration/pressurized CO2. key basic conditions, suggested by control species that have suppressing Overall, study highlights critical needs investigations in broader region.