Photocatalytic Nanocomposite Polymers for Enhanced Water Purification Applications

The need for clean and drinkable water cannot be understated as it is the prerequisite for all human and economic development. Unfortunately, 780 million people do not have access to clean water, resulting in the death of over 2 million children every year. Literature has shown that photocatalytic nanoparticles enhance the chemical degradation of organic pollutants when exposed to UV light. The major limitation in this application is due to lack of availability of a UV radiation. This research developed a cellulose based nanocomposite film that uses visible light to degrade simulated organic pollutants through catalytic photo-redox reactions. Increasing the redox potential will also increase the potency of the nanocomposite, so various methods of enhancing electron transfer were implemented. Dye sensitization, surface modifications, and metal deposition on the nanoparticles were found to improve the transfer of electrons from the semiconductor to the pollutant. In addition to increasing the rate of reaction, Ag-functionalized TiO₂ nanoparticles resulted in a synergistic antimicrobial effect, which eliminated E. Coli and S. Aureus from the water samples. Both dye sensitization and noble metal deposition showed a 25% increase in the amount of pollutant that was chemically degraded in comparison to unmodified TiO₂. Additionally, surface modifications of the nanoparticles by covalently bonding new functional groups to the nanoparticle surface facilitate metal complexation, removing heavy metal ions from the sample.