Sequestration of CO2 into CaCO3 using Carbonic Anhydrase Immobilization on Functionalized Aluminum Oxide

To develop the technology for CO2 sequestration, the free and immobilized carbonic anhydrase treatment was performed. The amount of dissolved CO2 was increased by 3-fold after enzyme treatment of 5 ppm, and the amount of calcium carbonate increased linearly as the CaCl2 was increased to 100 mM. To immobilize the carbonic anhydrase, an aluminum oxide carrier surface was functionalized with octadecyltrichlorosilane, 1H,1H,2H,2H-perfluoroctyltriethoxysilane, 3-aminopropyltriethoxysilane, 3-mercaptopropyl triethoxysilane, chlorotrimethylsilane 3-cyanopropyltrichlorosilane or 3-glycidyloxypropyltriethoxysilane. The best effect among these substances was revealed with 3-aminopropyltriethoxysilane; the efficacy of the immobilized carbonic anhydrase was at over 99%, and even when it was repeatedly used up to 40 times, the efficacy of the immobilized enzyme was more than 80%. The optimal conditions for the immobilized enzyme were 60oC and pH 7.0.