Photocatalytic Membranes for Producing Ultrapure Water

60879 Semiconductor plants are currently in need of ultrapure water with <1 ppb total organic carbon (TOC) levels, yet current methods to produce ultrapure water are energy intensive and limited to minimum TOC levels in the range 2 ¿ 5 ppb. This project will develop a novel photocatalytic membrane that provides intimate mixing of the dilute stream with the catalyst and activating photons. In addition, a highly active TiO2 photocatalyst coating will be developed and applied to the novel membranes. Phase I demonstrated a capability to achieve TOC levels of less than 1ppb using the innovative catalyst support structure. A preferred catalyst coating material and application method was also determined. In Phase II, the membrane design will be analytically optimized to maximize mass transfer rates and volumetric photoexposure of the treatment stream. Catalyst coating materials and methods will be refined and the fabrication process will be scaled-up to a pilot scale reactor that will be tested in the laboratory and then in the field at a selected semiconductor fabrication plant. Commercial Applications and Other Benefits as described by the awardee: The three primary industries that use ultrapure water are semiconductor fabrication, pharmaceuticals and biotechnology, and power generation. The total estimated market for ultrapure water is $190 Million annually. The semiconductor industry will benefit from the new water purity levels enabled by the proposed technology for both raw water and recycled water. This technology is needed in order to keep pace with the water purity guidelines set forth in the National Technology Roadmap for Semiconductors.