Water Resources Research Act Program

Details for Project ID 2015MN362B

Improving the (Bio)fouling and Mechanical Resistance of Ultrafiltration Membranes for Drinking Water Production

Institute: Minnesota
Year Established: 2015 Start Date: 2015-03-01 End Date: 2016-02-28
Total Federal Funds: $30,000 Total Non-Federal Funds: $60,000

Principal Investigators: [ENCODING ERROR]

Abstract: Ultrafiltration (UF) is a membrane-based water separation process widely used in water/wastewater treatment and drinking water production. In the state of Minnesota, UF is used at the Columbia Heights Membrane Filtration Plant, which supplies the city of Minneapolis with up to 78 million gallons of drinking water per day. Membrane fouling is a major obstacle towards improving the sustainability of membrane filtration processes such as UF. During fouling, the membrane water permeability decreases due to the adsorption of feed-borne solutes, particles or bacteria. The loss of throughput must be overcome by increasing the transmembrane pressure, or by backwashing of the membrane between filtration cycles, both of which may cause mechanical stresses that could lead to membrane failure, and, ultimately, higher operating costs. Often times, fouling is irreversible and the membrane has to be replaced. In order to make UF filtration a sustainable technological solution to water supply problems, there is a clear need to develop UF membrane materials that are both fouling-resistant and mechanically robust. An innovative way of tailoring material properties is through functionalization with nanomaterials such as graphene oxide (GO), which is both hydrophilic and possesses bactericidal activity. In addition, as one of the strongest materials ever measured, GO can be used as an additive in composite materials to improve their mechanical properties. The research proposed herein has the two-fold objective of improving fouling resistance and membrane mechanical properties via functionalization with GO nanosheets. Ultrafiltration membranes will be functionalized following a novel membrane fabrication protocol, in which surface modification with GO is assisted by the formation of a self-adherent polydopamine coating. We present preliminary results demonstrating the proposed surface functionalization. Given the possibility of forming polydopamine films on a wide variety of organic and inorganic surfaces, we anticipate the applicability of our functionalization protocol to a broad range of materials and polymeric UF membrane systems (i.e., those based on polysulfone, poly(ether sulfone), cellulose acetate, polyacrylonitrile, poly(ether imides), aromatic polyamides, poly(vinyledene fluoride), and poly(vinyl pyrrolidone)). The GO-UF membrane materials developed in this project will exhibit organic and biofouling-resistant surface properties derived from the GO coating the membrane surface. In addition, owing to the embedding of GO nanosheets in the polymeric matrix, we expect the tensile properties of the GO-UF membranes to improve significantly compared to those of conventional polymeric materials. We surmise that advanced materials such as those proposed herein could lead to lower operating costs at Membrane Filtration Plants in Minnesota and elsewhere. Graphene oxide nanomaterials are the subject of significant current interest given their numerous applications. We believe, therefore, that the experimental protocols that will results from this study could lead to future, extramurally-funded investigations on bacteria-graphene interactions.