A Novel Separation Technology for Biofuel Harvesting from Wastewater

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This research program will develop a membrane separation technology for efficiently harvesting biofuel from wastewater that is economically and environmentally sustainable. Although technology that converts organic materials in wastewater into biofuels (e.g., biomethane, bioethanol and biodiesel) currently exists, these biofuels are in non-usable forms such as dissolved gas or liquid mixtures, and therefore necessitates an additional extraction step. One potential solution – membrane separation process – is energy-efficient and requires a small environmental footprint. However, currently there exists no effective membrane technology for separation of the produced biofuels due to low selectivity and fouling that make the membrane processes ineffective and expensive.******This proposal addresses two key challenges of current membrane technology to achieve highly efficient biofuel harvesting from wastewater: (1) low selectivity and (2) severe fouling. To achieve high selectivity, an extremely wetting resistant omniphobic membrane will be developed. This membrane will be placed between a feed solution (biofuel and wastewater mixture) and a draw solvent (organic solvent that has high solubility for biofuel but low solubility for water). The solubility difference drives biofuel as a gas into the draw solvent, while water is rejected due to the poor solubility in the draw, leading to a high selectivity of biofuels. In addition, a self-cleaning surface coating will be developed using stimuli-responsive materials for membranes sustainable in the long run. In response to external stimuli such as voltage change, the surface coating of the membrane disrupts, removing the deposited foulants on the membrane surface. As a potential application, we will demonstrate the long-term sustainable harvesting of biomethane from an effluent of anaerobically treated wastewater. ******The developed technology will significantly boost renewable energy supply and reduce greenhouse gas (GHG) emissions. Economically, methane from wastewater can supplement up to approximately 21% of energy use in residential areas in Canada. Environmentally, the full utilization of biomethane from wastewater is equivalent to removing GHG emitted from more than half a million cars in Canada. In the long run, the proposed research program would pave a new path for further innovations in the water-food-energy nexus, providing significant economic and environmental benefits to Canada.