129 The Photocatalytic Enhancement of the SODIS Method

Wednesday, November 4, 2009: 11:40 AM
Longhorn (Camino Real Hotel)
Tonia M. Perez , Department of Chemistry, Wayland Baptist University, Plainview, TX
Jonathan M. Carey , Department of Chemistry, Wayland Baptist University, Plainview, TX
Elida G. Arsiaga , Department of Chemistry, Wayland Baptist University, Plainview, TX
Zachariah J. Hawkins , Department of Chemistry, Wayland Baptist University, Plainview, TX
Joel E. Boyd , Department of Chemistry, Wayland Baptist University, Plainview, TX
Solar water disinfection (SODIS) and a photocatalytic technique known as solar photocatalytic disinfection were investigated to assess the effectiveness in removing both chemical and biological contaminants from water. Poly(methyl methacrylate) (acrylic) and polyethylene terephthalate (PET) bottles each with and without an internal layer of titania photocatalyst, were compared for their ability to sterilize E. coli K-12, and degrade methyl orange and the algal toxin Microcystin-LR. Both the coated and uncoated acrylic bottles inactivated 650 mL of water containing 3,000,000-5,000,000 colony forming units per mL of E. coli within 40 min of sunlight exposure. Five hours of sunlight was sufficient to reduce a 10 ppm concentration of methyl orange by 61 % using the titania coated acrylic bottles. The initial 87 ppb concentration of Microcystin-LR was reduced by 70 % after 7 hours of sunlight exposure in the titania coated acrylic bottles. The UV transparency of the acrylic materials is significantly greater than that of the PET bottles used, making acrylic bottles an extremely attractive alternative to traditional PET SODIS bottles.  The addition of a photocatalytic titania layer to SODIS bottle interiors increases the capability for photocatalytic degradation of chemical contaminants which is lacking in ordinary SODIS applications designed solely for microbial inactivation.
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