The influence of membrane separation technique in the biodiesel and bioethanol production process: a review

Biodiesel and bioethanol have physicochemical properties and environmental advantages that make them promising alternative energy sources to replace petroleum-derived fuels. However, some impasses related to the manufacturing process, separation, and purification of biofuels make the final cost of obtaining the product high. In this context, the selection of alternative, sustainable technologies that present high performance, such as the membrane separation process, can be used to improve the biodiesel and bioethanol production process. Thus, this review article discusses the possibilities and advantages of incorporating membrane technology in biodiesel and bioethanol production. In the biodiesel manufacturing process, membranes allow the recovery and reuse of reagents in transesterification and reduce the time for phase separation and water consumption in the biodiesel purification step. In the bioethanol production process, the use of an integrated membrane system can facilitate the continuous process of biomass hydrolysis, fermentation, and dehydration, allowing recovery of enzymes and cells, removal of inhibitory products, and improving bioethanol yield, besides decreasing energy consumption through distillation membranes. Thus, membranes can overcome some difficulties faced in conventional biodiesel and bioethanol production, but further development of the process is still needed to make it applicable on an industrial scale.