Carbon dioxide diffusion: A molecular dynamics study for Microalgae Biofixation Technology

Global warming has been a very critical issue for the past decades which is primarily due to carbon emissions brought by rapid industrialization. To address this, various strategies have been introduced to lessen environmental impacts and reduce carbon dioxide emission. Biological approach using microalgae is one of the most promising methods for the direct conversion of carbon dioxide. An atomic scale analysis is of great importance as it provides information beyond what traditional experiments can offer. The present study involves an atomic level of analysis on the carbon dioxide absorption intended for the development of microalgae biofixation method. The study was conducted using Molecular Dynamics simulations to analyze the effects of temperature and salinity on the dynamics and transport of carbon dioxide into the microalgae lipid bilayer. A total of 20 simulation sets equilibrated at temperature from 300 to 330 K and salinity level of 0.18 to 0.55 M was undertaken. The permeation coefficient of carbon dioxide molecules was calculated using the inhomogeneous solubility diffusion model while the force auto correlation function was used to estimate the diffusion coefficient. The resulting transport mechanisms of carbon dioxide showed an increasing pattern with increasing temperature and salinity despite membrane pathway compression. The highest calculated diffusion coefficient of 7.7101x10^-5cm²s^-1 was at 330 K and 0.05 M salinity level while the permeation coefficient was 2.3994x10^-3cms^-1 at 330 K and 0.55 M. Hence, the study suggests that the mobility of carbon dioxide molecule increases with linearly with temperature.