title: Photocatalytic degradation of methylene blue and inactivation of pathogenic bacteria using silver nanoparticles modified titanium dioxide thin films.
abstract: Titanium dioxide (TiO2) is a well-studied photocatalyst that is known to break down organic molecules upon ultraviolet irradiation. TiO2 thin films were fabricated on glass substrates using the doctor-blade procedure, the film surface was modified with silver nanoparticles to increase its visible light response. The Ag-TiO2 films were characterized by transmission electron microscopy, scanning electron microscopy equipped with energy dispersive spectrometry and X-ray diffraction. The photocatalytic degradation of methylene blue (MB) and inactivation of Gram-negative bacteria Escherichia coli and Gram-positive bacteria Staphylococcus aureus were studied. The modified films presented enhanced photocatalytic efficiency and can decompose MB solution two-times faster than the unmodified TiO2 films, under illumination of sunlight. A nominal degradation (15 %) was observed in control MB under sunlight. The degradation efficiency of Ag-TiO2 films slightly decreased after five consecutive experiments. Ag-TiO2 films revealed very effective bactericidal activity against both E. coli and S. aureus. The photocatalytic inactivation toward E. coli and S. aureus showed a similar trend with much higher effectiveness toward E. coli under the same experimental conditions. The inactivation efficiency was maximized and reached 95 % for S. aureus and 97 % for E. coli, after 180 min incubation. These results demonstrate the potential of application of Ag-TiO2 photocatalysis as a method for treatment of diluted waste waters in textile industries.
authors: Department of Radiation Microbiology, National Center for Radiation Research and Technology (NCRRT), Atomic Energy Authority, P.O. Box 29, Nasr City, Cairo, 11731, Egypt, haythammibrahim@yahoo.com.
authors: Haytham M M
authors: HM
authors: Ibrahim
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology; D002384:Catalysis; D004926:Escherichia coli / Q000187:drug effects*; D053768:Metal Nanoparticles / Q000737:chemistry; D008751:Methylene Blue / Q000737:chemistry*; D055668:Photochemical Processes; D012834:Silver / Q000737:chemistry*; D013211:Staphylococcus aureus / Q000187:drug effects*; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; C009495:titanium dioxide; D012834:Silver; D014025:Titanium; D008751:Methylene Blue