Kinetic study of photocatalytic degradation of the emerging contaminant bisphenol A using N–TiO2 in visible light: a study of the significance of dissolved oxygen
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This study compares the tracking of bisphenol A (BPA) degradation by three analytical techniques: liquid chromatography mass spectrometry (HPLC–MS), ultraviolet/visible (UV–Vis) spectroscopy and dissolved oxygen (DO) content. In each evaluation method, the photochemical behavior of TiO2 and N–TiO2 under visible light confirmed the relationship between the adsorption and photodegradation processes, with the reaction analysis indicating the possibility of two photocatalytic mechanisms: conventional photocatalyzed radical oxidation and lattice oxygen driven oxidation. The first one concerns HPLC, where the average half-lives (t1/2) were 38 min (5% N–TiO2), 60 min (1% N–TiO2) and 64 min (TiO2), these values vary in 12% if compared with the values obtained by UV–Vis spectroscopy. The second mechanism showed a decrease in the initial concentration by more than 50% (8 mg L−1) after 3 h. The solution of doped photocatalysts is tracked best by DO measurement. The results presented here confirm that the efficiency of photocatalytic oxidation (EPO) of a reaction is highly related to the DO content, given that dissolved O2 proactively causes the release of radicals on the surface of excited materials under the action of visible light, thus increasing the BPA degradation rate. The quantum yield of BPA disappearance was below 0.1 for all the materials.
KeywordsSemiconductor Photocatalysis Endocrine disrupting Surface mechanism
DLS wishes to thank CONACyT for the financial support (Master and mixed scholarship). Dr. Santiago I. Suárez are gratefully acknowledged for valuable support of PROMEP Nuevo PTC DSA/103.5/16/10510. R. Zanella acknowledges the financial support granted by PAPIIT 105416, UNAM, Mexico. Authors thank to PAICYT IT 404-15 and IT 510-15. The authors thank the Materials’ Laboratory of Facultad de Ingenieria Civil-UANL for allowing them to perform the described experiments.
- 4.Chao-Yin K, Chung-Hsin W, Jui-Tai W, Yu-Ren C (2015) Synthesis and Characterization of a phosphorus-doped TiO2 immobilized bed for the photodegradation of bisphenol A under UV and sunlight irradiation. Reac Kinet Mech Cat 114:453–766Google Scholar
- 7.Manzo-Robledo A, Cruz López A, Flores Caballero AA, Zaldivar Cadena AA, López M, Vázquez Cuchillo O (2015) Photoelectrochemical properties of sol–gel synthesized titanium dioxide nano-particles using different acids: X-ray photoelectron spectroscopy reveals the induced effect of hydrolysis precursor. Mater Sci Semi Proc 31:94–99CrossRefGoogle Scholar
- 8.Hirakawa T, Koga C, Negishi N, Takeuchi K, Matsuzawa S (2009) An approach to elucidating photocatalytic reaction mechanisms by monitoring dissolved oxygen: effect of H2O2 on photocatalysis. Appl Catal B 87:46–55Google Scholar
- 10.Del Ángel-Sánchez K, Vázquez-Cuchillo O, Salazar-Villanueva M, Sánchez Ramírez JF, Cruz-López A, Aguilar-Elguezabal A (2011) Preparation, characterization and photocatalytic properties of TiO2nanostructured spheres synthesized by the Sol-Gel method modified with ethylene glicol. J Sol–Gel Sci Technol 38:360–365CrossRefGoogle Scholar
- 15.Klauson D, Gromyko I, Dedova T, Pronina N, Krichevskaya M, Budarnaja O, Oja Acik I, Volobujeva O, Sildos I, Utt K (2015) Study on photocatalytic activity of ZnO nanoneedles, nanorods, pyramids and hierarchical structures obtained by spray pyrolysis method. Mater Sci Semi Proc 31:315–324CrossRefGoogle Scholar
- 29.Levenspiel O (2015) Ingeniería de las reacciones químicas. Limusa, MexicoGoogle Scholar
- 31.Lente G (2015) Deterministic kinetics in chemistry and systems biology. The dinamics of complex reaction networks. Spinger, BerlinGoogle Scholar
- 33.Ali AM, Emanuelsson EAC, Petterson DA (2011) Conventional versus lattice photocatalysed reactions: implications of the lattice oxygen participation in the liquid phase photocatalytic oxydation with nanostructired ZnO thin film on reaction products and mechanism at both 254 and 340 nm. Appl Catal B 106:323–336CrossRefGoogle Scholar
- 34.Miyauchi M, Ikezawa A, Tobimatsu H, Irie H, Hashimoto K (2004) Zeta potential and photocatalytic activity of nitrogen doped TiO2 thin films. Phys Chem Chem Phys 6:865–870Google Scholar