Accelerated CO2 capture in hybrid solvent using co-immobilized enzyme/complex on a hetero-functionalized support

- A hybrid solvent system was developed for optimized CO2 absorption and desorption.
- The HFS containing enzyme/Zn-Im shows 21.65 wt% CO2 uptake in hybrid solvent.
- Enzyme/Zn-Im: HFS in hybrid solvent has 1.57 times higher desorption kinetics.
- CA was highly stable in the hybrid solvent and could be reused multiple times.

There has been increasing interest in the development of solvent systems for efficient and less energy intensive CO2 capture and desorption. In this work, we have developed a hybrid solvent system (30 wt.% MEA + 7.5 wt% PZ + 15wt% K2CO3) containing a thermo-stable carbonic anhydrase (CA) and Zn complex (Zn-Im) together on a hetero-functional support (HFSCaCO3/H3BO3/SiO2) (termed as CA/Zn-Im: HFS). The hybrid solvent containing CA/Zn-Im: HFS exhibit excellent gravimetric CO2 uptake (21.65 wt%) over the neat hybrid solvent (13.75 wt%). Gravimetric and pressure drop experiments confirmed that HFS and Zn-Im plays key role in improving the CO2 capture activities of CA in hybrid solvent. Low temperature desorption (90 °C) suggested that the hybrid solvent containing CA/Zn-Im: HFS has 1.57 times higher desorption kinetics compared to the neat hybrid solvent. Moreover, CA was highly stable in the hybrid solvent medium and could be reused for 15 consecutive cycles with retention of 90% of its initial activity. The development in various key aspects of CO2 capture suggested that the hybrid solvent with CA/Zn-Im: HFS is an efficient solvent system to improve conventional amine based scrubbing technology.

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