SBIR Phase II: Carbon Nanotube Enhanced Membrane Distillation for Sea and Brackish Water Desalination, and the Treatment of Saline Waste Water

The broader impact/commercial potential of this Small Business Innovative Research (SBIR) project arises from addressing one of the world's major challenges - the need for water. We address this problem through the development of a novel technology for economic desalting for inexpensive clean water generation and the treatment of high concentration saline waste. There is no "one size fits all" approach to water desalting. Many factors such as salt concentration, the presence of specific ions, energy cost, pretreatment requirements and capital investments are important considerations in selecting a desalting technology. The carbon nanotube immobilized membrane distillation (CNIM-MD) being developed here offers many advantages such as the ability to utilize waste heat and solar energy and as well as the ability to handle high salt concentrations. The CNIM-MD is being designed with the aim of treating high salinity water (above 750,000 ppm dissolved solids that are not normally handled by reverse osmosis (RO). The primary target market for CNIM-MD is concentrating brine for zero liquid discharge (ZLD) where brine is concentrated and the solids are eventually precipitated out, pure water is reused and no water is discharged as industrial effluents. Other potential markets for CNIM-MD are treating RO reject to increase pure water yield, and the treatment of produced water in oil and gas industry. This SBIR Phase II project proposes to scale up the CNIM fabrication process via roll-to-roll (R2R) coating, demonstrate CNIM-MD at pilot scale and initiate commercial sales. The intellectual merit of the project lies in the novel approach to design and synthesis of scalable membrane systems for water desalination, and the treatment of saline waste. The CAPEX and OPEX of CNIM-MD compared to thermal evaporators is compelling, and CNIM-MD can be a major component of a hybrid ZLD treatment train integrating membrane technology with thermal evaporator. In short, the development of CNIM-MD will be a major development in the area of membrane treatment of high concertation brine. The success in the synthesis of novel membrane architecture such as CNIM will impact in many areas beyond desalination, which include carbon capture, gas purification, emission control, dehumidification as well as capturing pure water from the atmosphere. They have potential to impact major industries such as power plants, petrochemicals, oil and gas exploration, dehumidification, air purification, and food processing. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.