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Effect of Carbonic Anhydrase on CaCO3 Crystallization in Alkaline Solution

Molva, Murat, Kilic, Sevgi, Ozdemir, Ekrem
Energy & Fuels 2016 v.30 no.12 pp. 10686-10695
biocatalysis, calcium carbonate, calcium hydroxide, carbon dioxide, carbonate dehydratase, cattle, crystallization, foams, methodology, pH, polyurethanes
The effect of bovine carbonic anhydrase (CA) on calcium carbonate (CaCO₃) crystallization was investigated. A new method was developed to estimate the biocatalytic activity of CA in alkaline solution. The CA was immobilized within polyurethane (PU) foam, and compared its biocatalytic activity with the free-CA and bare-PU foam. A minireactor was created in a calcium hydroxide (Ca(OH)₂) solution in order to control the CO₂ transfer rate, and reproducible results were obtained. It was found that the free-CA lost its activity in less than 6 min at pH 12.5 in alkaline Ca(OH)₂ solution. The CaCO₃ crystallization rates for the immobilized-CA were found to be a U-shape, relatively lower at lower immobilized-CA amounts compared to those for the free-CA and bare-PU foam and higher when the amount of immobilized-CA increased. It was concluded that a higher immobilized-CA amount is required to accelerate the CaCO₃ crystallization rates in Ca(OH)₂ solution.