A Zn-N mimetic carbonic anhydrase for enhancing CO2 solidification and mechanical properties of cement-based materials

Cement-based materials without reinforcement have the advantage of CO2 solidification potential. However, such CO2 solidification under natural conditions usually proceeds slowly. In this study, based on the catalysis principle of CO2 hydration reaction by natural carbonic anhydrase, mimetic carbonic anhydrase with Zn-N bond was synthesized and its influences on CO2 solidification rate of cement paste were investigated. The results demonstrated that mimetic carbonic anhydrase with the Zn-N bond exhibited strong catalytic ability to p-nitrophenyl acetate. It increased the HCO3− concentration in both HEPES buffer solution and cement paste pore solution within a short time, and thus promoted the formation of calcium carbonate in a solution with Ca2+. The incorporation of mimetic carbonic anhydrase can not only improve the mechanical properties of cement-based material but also enhance the mass percentage of CaCO3 in cement paste based on TG tests, indicating that the carbonation efficiency of cement paste was increased.