Online Detection of Reactive Oxygen Species in Ultraviolet (UV)-Irradiated Nano-TiO2 Suspensions by Continuous Flow Chemiluminescence

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• 作者：Dabin Wang ; Lixia Zhao ; Liang-Hong Guo ; Hui Zhang
• 刊名：Analytical Chemistry
• 出版年：2014
• 出版时间：November 4, 2014
• 年：2014
• 卷：86
• 期：21
• 页码：10535-10539
• 全文大小：251K
• ISSN：1520-6882

文摘

Reactive oxygen species (ROS) play very important roles in the photocatalytic reactions of semiconductors. Using a continuous flow chemiluminescence (CFCL) system, we developed three methods for the selective, sensitive, and online detection of O₂^{鈥⒙犫€?/sup>, 鈥H, and H₂O₂ generated during ultraviolet (UV) irradiation of nano-TiO₂ suspensions. TiO₂ nanoparticles were irradiated in a photoreactor and pumped continuously into a detection cell. To detect O₂鈥⒙犫€?/sup>, luminol was mixed with TiO₂ before it entered the detection cell. For the detection of short-lived 鈥H, phthalhydrazide was added into the photoreactor to capture 鈥H, and then mixed with H₂O₂/K₅Cu(HIO₆)₂ to produce chemiluminescence (CL). To detect H₂O₂, an irradiated TiO₂ suspension was kept in darkness for 30 min, and then mixed with luminol/K₃Fe(CN)₆ to produce CL. The selectivity of each method for a particular ROS was verified by using specific ROS scavengers. For a given ROS, a comparison between CL and conventional method showed good agreement for a series of TiO₂ concentrations. The sensitivity of CL method was approximately 3-, 1200-, and 5-fold higher than the conventional method for O₂鈥⒙犫€?/sup>, 鈥H, and H₂O₂, respectively. To demonstrate the utility of the methods, ROS in three different types of TiO₂ suspensions was detected by CFCL. It was found that photodegradation efficiency of Rhodamine B correlated the best (R2 > 0.95) with the amount of photogenerated 鈥H, implying that 鈥H was the major oxidant in Rhodamine B photodegradation reaction. CFCL may provide a convenient tool for the studies on the reaction kinetics of ROS-participated decomposition of environmental contaminants.}