Solar Disinfection of Drinking Water with Polyethylene Terephthalate Bottles Coated with Nano-Titanium Dioxide

Water disinfection processes in the presence of titanium dioxide as a photo-catalyst material provide an interesting route to destroy contaminants, being operational in the UV-A domain with a potential use of solar radiation. In recent years, advanced oxidation processes (AOP) have been developed to meet the increasing need of an effective wastewater treatment. AOP generates powerful oxidizing agent hydroxyl radicals which completely destroy the pollutants in waste water. Solar disinfection of drinking water with polyethylene terephthalate (PET) bottles coated with photo-catalyst TiO2 has been shown to be very effective. The study is based on comparison between three systems for treating contaminated water samples using PET bottles. First system was a PET untreated bottle, the second system was a PET bottle coated with black paint on its outer surface. Finally the third system was a PET bottle coated also with a black coat on its outer surface and its inner part was treated with citric acid solution to enable np-TiO2 to cover the surface later on, then 0.2 g of np-TiO2 powder (of particle size <25 nm, Sigma-Aldrich) was added. The total bacterial accounts were determined to monitor the effect in the three systems. The experimental results have shown that disinfecting water with merely UV was less effective than combining the bottle with heat effect, and adding TiO2 film was further more benefited. This work can be applied in rural areas, with no technical support or need for expensive/dangerous chemicals for drinking safe water even if is stored for two days