Ionization controls for biomineralization-inspired CO2 chemical looping at constant room temperature

Living organisms such as corals can carry out CO2 looping efficiently via biomineralization under ambient conditions. Inspired by this natural process, we establish a solution system of calcium acetate-ethanol-water (Ca(Ac)2-C2H5OH-H2O) for CO2 chemical looping at constant room temperature. The CO2 capture is achieved by its reaction with Ca(Ac)2 to form calcium carbonate (CaCO3) mineral and HAc in the binary solvent with a high C2H5OH content. However, an increase in the H2O content in the system triggers acetic acid (HAc)-induced CaCO3 dissolution to release CO2. The system can be recovered for CO2 capture readily by the replenishment of C2H5OH. This biomimetic mineralization-based CO2 capture/release is controlled by the ionization states of the electrolytes, and is precisely regulated in the C2H5OH-H2O binary solvent. Our attempt highlights the fundamental principle of solution chemistry in reaction control and provides a bioinspired strategy for CO2 capture/release with very low cost and easy availability.