Final Report: Efficient Water Purification Using TIO2 and Novel Activation MethodEPA Contract Number: EPD13032
Title: Efficient Water Purification Using TIO2 and Novel Activation Method
Investigators: Miermont, Adeline
Small Business: Imaging Systems Technology, Inc.
EPA Contact: Manager, SBIR Program
Project Period: May 15, 2013 through November 14, 2013
Project Amount: $80,000
RFA: Small Business Innovation Research (SBIR) - Phase I (2013) RFA Text | Recipients Lists
Research Category: Small Business Innovation Research (SBIR) , SBIR - Water
In response to EPA's topic of Drinking Water, Imaging Systems Technology (IST) has investigated coating ultraviolet (UV) Plasma-shellsTM with Titanium (IV) Dioxide (TiO2) to produce a low cost, rugged, portable and highly efficient water purification system. Plasma-shellsTM are tiny hollow gas encapsulating beads. When energized, Plasma-shellsTM produce light including UV light. UV activated TiO2 is a powerful catalyst that can be used in the breakdown of chemicals and the destruction of pathogens in contaminated water. Figure 1 is a photograph of UV-A Plasma-shellsTM fabricated under this SBIR research effort. Plasma-shellsTM are energized and glow in the presence of an electric field.
The TiO2 photocatalytic process is a conceptually simple and promising technology for lysing bacteria and neutralizing contaminants. However, efficiently activating the TiO2 with standard UV lamp bulbs is problematic. Specifically, because TiO2 requires UV activation, it must be close to the UV source. Past studies have focused on mixing TiO2 powder directly into the water and exciting with a UV source. However, this is inefficient. As distance from the lamp increases, murky water and TiO2 block or attenuate the UV. Thus, only water nearest to the UV lamps is purified. This slows the process and reduces efficiency. Additionally, the UV bulbs (quartz tubes) do not have a high surface area further reducing the efficiency. They also are very fragile and expensive. Replacing the fragile quartz tubes with UV-A Plasma-shells will result in a significantly improved system. The UV-A producing surface area will be increased by several orders of magnitude, and the UV-A light source will be placed directly into water, making the system much more efficient.
IST has successfully coated UV-A Plasma-shellsTM with anatase TiO2 and designed an electronic configuration that allows the Plasma-shellsTM to be energized while submerged in water as shown on Figure 2. The Plasma-shellsTM were assembled into a ladder configuration where the UV-A Plasma-shellsTM were electroded on both ends and sandwiched between two substrates. The connections between the Plasma-shellsTM and the substrates were waterproofed using epoxy. TiO2 coated Plasma-shellsTM were assembled into a ladder configuration and their photocatalytic activity was tested on the decomposition of methylene blue. Based on the results, it was concluded that the amount of TiO2 present on the surface of the Plasma-shellsTM was not enough to provide sufficient photocatalytic power to efficiently decompose methylene blue. Optimization of the system led to the fabrication of rectangular bars coated with anatase TiO2. TiO2 coated bars used in combination with UV-A Plasma-shellsTM ladder (Figure 3) resulted to the complete decomposition of methylene blue, making this system the most efficient and promising to date.
Under this Phase I research SBIR, IST has developed a promising photocatalytic water purification system based on its novel lighting technology, Plasma-shellsTM. IST will continue working on improving and testing this system as well as qualifying it in different water purification settings with the help of the EPA office in Cincinnati, OH.
IST has worked closely with the EPA. Indeed, the EPA is very interested in the Plasma-shellsTM technology for various applications, including water purification. IST currently is developing a Cooperative Research and Development Agreement (CRADA) with their Cincinnati EPA groups. IST also has secured two purchase orders from the EPA to start developing a UV Plasma-shellsTM filter cartridge system. As shown on Figure 4, the proposed design shows circular boards that would be populated with UV Plasma-shellsTM and placed into a filter housing. These systems will be evaluated for water purification under different conditions.
IST also has been working on a Life Cycle Assessment (LCA) of the proposed technology the EPA office in Cincinnati. It is collecting environmental impact data on the fabrication, use and ultimately disposal of the Plasma-shellTM technology. Initial investigation indicates that the technology has advantages over UV LEDs in the area of life, cost and environmental impact.
IST has fabricated samples of UV-A lighting tiles for an Aquionics purchase order. Aquionics will be testing and qualifying the UV-A Plasma-shellsTM tile for different applications, including photo-curing. IST also has attended WEFTec in Chicago as a guest of Aquionics.
Finally, IST was selected by Foresight Commercialization Group to make a 5-minute video highlighting its technology that was shown at a trade show in China.