Development of CO2 permeation kinetic model for microalgae biofixation method

The persistent increase in carbon dioxide concentration in the atmosphere remains the main contributor to global climate change. This has prompted the international community and various researchers to design, develop and investigate materials to stabilize its growing threat. Materials for carbon capture technologies for flue gas emissions are already available and have been studied extensively. Materials such as zeolites, metal organics frameworks, activated carbon and carbon nanotubes have been proven to effectively capture carbon dioxide. However, these materials are very complex to prepare which makes it unfavorable for large scale production. One of the best-known methods is through the biological approach of using microorganisms such as microalgae that have higher conversion efficiency as compared to terrestrial plants. Apparently, its full potential has not been achieved due to variations in several cultivation parameters such as temperature and salinity, which have not been well understood in the current experimental studies. The study is conducted in the atomic level to demonstrate the effects of temperature and salinity on the transport processes of carbon dioxide molecules coming from the flue gas to the microalgae lipid membranes using molecular dynamics. The transport process was described through the calculation of free energies and diffusion coefficient of the carbon dioxide molecules across the membrane using the Cavity Insertion Widom method and Velocity Auto Correlation method. Also, the Space Filling Design was used to determine the experimental space for the calculation of permeation coefficient. The overall resulting transport mechanisms of the carbon dioxide molecule at different levels of temperature and salinity have shown no significant changes to its mobility as it permeates towards the intracellular part of the membrane. Despite the structural changes in the microalgae lipid membrane, the mobility of the carbon dioxide molecules remains to be spontaneous, therefore, this suggests that microalgaes carbon dioxide absorption remains unchanged despite undergoing phase transition