Influence of oxygen addition on photocatalytic oxidation of aqueous ammonia over platinum-loaded TiO2

• Published in: Applied catalysis. B, Environmental Vol. 138-139; pp. 294 - 298
• Main Authors: Shibuya, Satoshi, Aoki, Satoshi, Sekine, Yoshika, Mikami, Ikko
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 17.07.2013; Elsevier
• Subjects: Aqueous ammonia; Catalysis; Chemistry; Exact sciences and technology; General and physical chemistry; Photocatalysis; Photochemistry; Physical chemistry of induced reactions (with radiations, particles and ultrasonics); Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Titanium(IV) oxide; Water treatment; Titanium(IV) oxide; Water treatment; Photocatalysis; Aqueous ammonia; Binary compound; Titanium IV; Transition element compounds; Transition metal; Ammonia; Heterogeneous catalysis; Oxygen addition; Platinum; Oxidation; Titanium oxide; Environmental protection
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2013.03.003

•The decomposition rate was significantly increased by the addition of oxygen.•The influence of DO concentration on selectivity for nitrite and nitrate was examined.•The selectivity for nitrite and nitrate was suppressed as the initial concentration of ammonia was increased. The oxidation of aqueous ammonia over a platinum-loaded TiO2 photocatalyst was investigated for purification of wastewater. The reaction rate for the decomposition of aqueous ammonia was significantly increased by the addition of oxygen to the reaction system. The enhancement of charge separation efficiency due to consumption of photogenerated electrons by oxygen increased the decomposition rate. For dissolved oxygen (DO) concentrations below 0.09mM, the initial decomposition rate and the selectivity for nitrite and nitrate increased as DO concentration increased. Although the selectivity for nitrite and nitrate was over 90% for the initial concentration of ammonia ([NH3]i)=5.0mM under an air flow, the selectivity was suppressed as the initial concentration of ammonia was increased, e.g., 43% for [NH3]i=100mM.