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The photocatalytic activity of titanium dioxide (TiO 2 ) and gold (Au) modified TiO 2 (Au/TiO 2 ), supported in polymethylmethacrylate (PMMA) thin film, was evaluated in the photodegradation of Trypan Blue (TB) under sunlight irradiation. The effect of parameters such as the photocatalyst amount and pH on TiO 2 photocatalytic activity is investigated. Oxygen flow stream was applied to enhance the decomposition process of TB. The maximum photoactivity was attained using Au/TiO 2 -PMMA thin film at pH=2.

Chitosan is a nontoxic, eco-friendly, and biocompatible natural polymer which could be used in an extensive range of applications for example in the areas of membranes, biomedicine, hydrogels, wastewater treatment, food packaging. Moreover, chitosan based nanomaterials had high sorption capacities, chelating activities, stability, and versatility, that would be potentially applied as green reactants in various scientific and engineering applications. The current study involved the preparation of silver nanoparticles incorporated into chitosan thin films and used for various purposes including photo-oxidation of organic pollutants, heavy metal removal (Cd, Pb, Cr, and Fe) and antibacterial activity. The fabricated chitosan/silver (CS/Ag) bionanocomposites thin films were characterized by the ultraviolet-visible (UV-Vis) spectroscopy, transmission electron microscopy (TEM), and Fourier transforms infrared (FT-IR) spectroscopy. Furthermore, the prepared CS/Ag bionanocomposites had revealed good photodegradation rate, heavy metals removal and antimicrobial activity against gram-negative bacteria like E. coli, and gram-positive bacteria like G. bacillus, with increasing the loading of different concentrations of chitosan and silver nanoparticles incorporated into the prepared bionanocomposite thin films. Consequently, the prepared CS/Ag bionanocomposites are considered good candidates for wastewater treatment through photo-oxidation of organic pollutants, heavy metal removal as well as respectable antibacterial materials.

It is very important to improve the efficiency of water detoxification techniques. In this study, TiO2or gold-TiO2(Au/TiO2) nanocomposite-bound polythene beads were used for the photo-oxidation of rhodamine 6G (R6G) as a model of water organic pollutants. Simple thermal procedures were employed for anchoring TiO2or Au/TiO2nanocomposites to polythene beads. The results revealed that the synthesized Au/TiO2composites exhibited both considerably higher absorption capability of organic pollutants and better photocatalytic activity for the photo-oxidation of R-6G than pure titania. The better photocatalytic activity of the synthesized Au/TiO2composites film than that of the pure titania film was attributed to high capacity of light absorption intensity and easy diffusion of absorbed pollutants on the absorption sites to photogenerated oxidizing radicals on the photoactive sites.