Mineral carbonation for carbon utilization in microalgae culture

This paper presents a study on the combination of mineral carbonation with biomass production. Laboratory experiments were performed to investigate the growth of freshwater green microalgae Scenedesmus obliquus in the presence of dissolving mineral carbonates, such as nahcolite (NaHCO3) and nesquehonite (MgCO3·3H2O) at atmospheric conditions and 25 °C. The cell density of the algae biomass was determined using fluorescence measurements. A biochemical model was implemented to describe the evolution of the biomass and the consumption of carbon substrate. The parameter estimates show that the algae growth kinetics in the presence of either NaHCO3 or MgCO3·3H2O is similar and is comparable to the literature. Moreover, when MgCO3·3H2O is supplied, the algae appear to form clusters, which favor their separation from the solution. Overall, this work analyzes the potential to combine two carbon dioxide (CO2) utilization options, i.e., mineral carbonation and microalgae cultivation, and it demonstrates the feasibility of the process. However, control of the pH and the carbon dosage is required to attain optimal biomass productivity.