ABSTRACT
Simply coating 1 wt.% of platinum on titanium dioxide (TiO2) surface resulted in simple preparation of platinized TiO2 (Pt-TiO2). This study demonstrated the photodegradation of atrazine (ATZ) using either Pt-TiO2 or TiO2 as a photocatalyst under 352 nm light irradiation. The Pt-TiO2-catalyzed ATZ degradation reached 76% in 3 hours without adding H2O2 solution or aeration, which was more than 10% higher than the TiO2-catalyzed reaction. The decomposition product of Pt-TiO2-catalyzed ATZ degradation was mainly cyanuric acid. Thus, Pt-TiO2 as an effective photocatalyst has three main advantages in the photodegradation of ATZ under 352 nm irradiation. First, the coated Pt can facilitate the generation of appropriate amounts of OH radicals, so it can prevent the formation of over-oxidized TiO2. Second, aeration was not needed. Third, the excited electrons were mainly uni-directionally transferred to the catalyst surface to avoid recombination of electron-hole pairs.
Subject(s)
Atrazine/radiation effects , Photolysis , Platinum/chemistry , Titanium/radiation effects , Atrazine/chemistry , Catalysis/radiation effects , Hydrogen Peroxide/chemistry , Kinetics , Microscopy, Electron, Transmission , Oxidation-Reduction , Spectrophotometry, Ultraviolet , Triazines/chemistry , X-Ray DiffractionABSTRACT
Visible light-induced photocatalysis is potentially advantageous and could be an efficient approach to degrade contaminants because it can be used to selectively target specific wavelength for decomposition of organic contaminants in water and wastewater. This study demonstrates the photodegradation of sulfamethoxazole (SMX) using [Pt(3,3'-dicarboxy-2,2'-bpy)(1,2-benzenedithiolate)] (Complex 1)-sensitized and [Pt(4,4'-dicarboxy-2,2'-bpy)(1,2-benzenedithiolate)] (Complex 2)-sensitized titanium dioxide (TiO2) under blue or yellow light (420 or 580 nm, respectively) irradiation in water. The Complex 1-sensitized TiO2 photocatalytic oxidation of SMX reached almost 100 % removal under 420 nm irradiation for 3 h in water. In addition, the formation of hydroxyl radicals can be facilitated by bubbling O2 during the photodegradation in which an effective decomposition of SMX was observed. Based on HPLC and UV-Vis studies of the decomposed products, it was found that SMX underwent cleavage of aromatic rings during the photodegradation process.
