Membrane Biosorption: Recent Advances and Challenges

This paper reviews recent developments in membrane biosorption and focuses on features and performance of different configurations of membrane biosorption. Biofilm formation, its role, and optimization in biosorption application as well as challenges and strategies for future applications are also discussed. Biosorption has gained increasing attention for wastewater treatment process due to its advantages of high separation efficiency, environmentally friendly, high availability of biomass, and low cost. In addition, biosorbents are reusable since they can be regenerated by employing a wash solution. This also provides the possibility of recovering valuable sorbed components from the concentrated wash solution. It has been demonstrated in several studies that membrane can be used to improve the performance of sorption processes. Membrane biosorption displays interesting features including higher process efficiency and smaller footprint. The membrane enhances contact between the biosorbent and the sorbate (pollutant) resulting in an improved sorption kinetic. Membrane also helps to remove priority pollutant from a wastewater by providing a selective extraction and avoids the mixing between the biosorbent and wastewater. In addition, membrane can improve the contact between gas stream and biosorbent for gas removal from a waste gas stream. It is also possible for supplying bubble-less aeration which improves the biological growth of the biosorbent. Some reported studies show that combined membrane biosorption may allow one to achieve pollutant removal up to three times of the single biosorption process. However, there are several challenges that need to be addressed for membrane biosorption application, including diffusion limitation in membrane and uncontrolled biofilm formation. Therefore, it is imperative to identify membranes with appropriate characteristics as well as biofilm control strategies.