Biomineralization-Inspired Hydrogels Enable Thermodynamically Enhanced CO2 Hydration for Efficient CO2 Sequestration.

The massive emissions of carbon dioxide (CO2) have triggered serious ecological crises, presenting severe challenges for CO2 sequestration. Mineral carbon sequestration is a promising approach for the integration of carbon capture, utilization, and storage (CCUS). However, its reaction thermodynamic process is universally sluggish, and its in situ crystallization regulation strategies are insufficient. To address the above limitations, inspired by the rapid biomineralization of eggshells catalyzed by carbonic anhydrase (CA), we innovatively introduced amino-functionalized zeolitic imidazolate framework-8 (ZIF-8-NH2) to accelerate the thermodynamics of CO2 hydration and combined it with polyacrylamide (PAM) hydrogel with CaCl2 introduced to achieve in situ CaCO3 crystallization. Experimental results show that the carbon sequestration capacity reaches 7.12 mmol of CO2 ghydrogel-1. In terms of mechanistic interpretation, density functional theory (DFT) calculations confirm that ZIF-8-NH2 improves the adsorption performance for CO2, which is attributed to the strong interaction between -NH2 and CO2. Simultaneously, it reduces the transition state (TS) energy barrier in the hydration reaction pathway, accordingly expediting the thermodynamics process. Furthermore, the products can remove heavy metal copper ions with a removal rate of nearly 40%. This work provides a new bioinspired strategy for the design of mineral carbon sequestration materials and broadens the application potential of carbon sequestration products.