Amino acid promoted single-step carbon dioxide capture and mineralization integrated with polymer-mediated crystallization of carbonates

Integrated CO2 capture and mineralization is a promising technology for cutting CO2 emissions and associated environmental impacts. Two major challenges in CO2 mineralization in aqueous media are (1) the lack of green and energy-efficient processes and (2) limited applications of the produced carbonates. Here, we present a very efficient, environmentally friendly, and convenient integrated CO2 capture and mineralization method to produce functional calcium carbonate (CaCO3) particles. We use a gas diffuser reaction setup to bubble CO2 in liquid media containing reagents such as amino acid as CO2 absorption promotor, water-soluble polymers as crystal growth modifiers, and Ca2+ ions. Different concentrations of amino acid L-arginine with a fixed CO2 bubbling rate were investigated for Ca2+ conversion. At the optimized conditions, more than 90% Ca2+ was converted to CaCO3 within 5 min of CO2 bubbling at a nominal rate. Additionally, functional carbonates that could be used as dye, heavy metals adsorbents, and functional composite fillers are produced using crystal growth modifiers. The method is simple, efficient, eco-friendly, and could be used for CO2/Ca2+-rich industrial waste valorization.