Synthesis of nanocomposite membranes for thermally-driven desalination applications
What we’re doing: For thermally driven membrane processes to be a feasible desalination approach, the membranes must exhibit certain characteristics including high flux, high selectivity, mechanical stability at elevated temperatures, and resistance to fouling. However, the largest obstacle in the utilization of polymeric membranes in industrial applications is their intrinsic trade-off relationship between selectivity and permeability. Some inorganic membranes such as zeolite and carbon molecular sieves offer much higher permeability and selectivity than polymeric membranes but are expensive and pose a difficulty for large-scale manufacturing. Therefore, it is highly desirable to provide an alternate cost-effective membrane in a position above the trade-off curves between permeability and selectivity. Nanocomposite membranes are hybrid membranes containing solid, liquid, or both solid and liquid fillers embedded in a polymer matrix. Enhanced separation properties are accomplished by adding a dispersed phase to the polymer matrix, a net result of which should be an improvement in the separation properties of the overall membrane. In this project, we are synthesizing next-generation nanocomposite membranes using imogolite nanotubes, which are a naturally occurring mineral capable forming nanotubes. We are evaluating the performance of these new membranes in pervaporation desalination systems. Our intention is to use these membranes for desalinating produced waters having total dissolved solids concentrations in excess of 50,000 mg/L for which conventional membrane processes are impractical.
