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

Abstract

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 60^oC and pH 7.0.