Short Perspective on Membrane Integration in Microalgae Bioreactor for CO2 Capture

Abstract

The global warming issue has reached an alarming level due to the continuous increase of CO₂ and other greenhouse gas emissions. They are released into the atmosphere due to anthropogenic activities and contributions from many industries that employ coal, fuel oil, and natural gas. To achieve environmentally friendly and sustainable conditions, CO₂ capture is important. This article starts by discussing the comparison of several methods in CO₂ capture, continues with the performance of CO₂ capture in microalgae bioreactor (photo-bioreactor), and closed with the prospect of membrane integration in photo-bioreactor. There are physical, chemical, and biological methods for capturing CO₂. Physical method leads to expensive processes and chemical method leads to producing chemical waste. Biological method using microalgae is considered attractive and several factors affected the capture process, i.e. temperature, pH, light intensity, microalgae strain, types of bioreactor, CO₂ and toxic substances concentration (SO₂ and NO_x), and illumination cycle. This article discloses that airlift and flat panel photo-bioreactors are promising for CO₂ capture because of their high volumetric productivity, high photosynthetic efficiency, high gas transfer, and uniform mixing. Furthermore, membrane integration in photo-bioreactors increases the capture efficiency as it can produce fine bubbles for better CO₂ mass transfer into the medium. Therefore, microalgae cultivation combine with membrane process has a potential prospect for environmental remediation while producing valuable products from microalgae.