Integrated CO2 capture and mineralization: impact of biopolymers as crystal growth modifiers on calcium carbonate crystallization

Accelerated CO 2 mineralization can utilize billions of tons of CO 2 annually. However, its widespread use, especially in aqueous systems, is limited by the lack of profitable applications of the produced carbonates. This study examines the effects of CO 2 injection rate, reaction temperature, ultrasonication, and biopolymers (gelatin, xanthan, pectin) as crystal growth modifiers during integrated CO 2 capture and mineralization using arginine as a CO 2 absorption promoter. Our findings indicate that varying the CO 2 injection rate (0.1–0.9 L/min) has minor improvements in Ca 2+ conversion to CaCO 3 , with the Ca 2+ to CO 2 absorption promoter ratio being the primary factor. Higher CO 2 injection rates resulted in smaller crystal sizes, while increased reaction temperatures improved Ca 2+ conversion to CaCO 3 and reduced vaterite content. Ultrasonication produced smaller (0.39 ± 0.07 μm), spherical porous vaterite particles. Gelatin caused excessive foaming, while xanthan led to particle agglomeration. Pectin yielded the best results, producing well-separated, homogeneous spherical vaterite particles. The consistent production of well-dispersed spherical porous CaCO 3 particles through aqueous CO 2 mineralization under ambient conditions paves the way for their high-end applications in industrial contexts. • Integrated CO 2 capture and mineralization to functional CaCO 3 with green reagents. • Biopolymers gelatin, xanthan, and pectin are used as crystal growth modifiers. • Ca 2+ to CO 2 absorbent ratio controls the Ca 2+ conversion to CaCO 3 . • Ultrasonication produces smaller spherical porous vaterite particles. • Pectin produces well-separated, homogenous spherical vaterite particles.