PhotoCatalytic Synthesis Group, MESA+Institute for Nanotechnology, Faculty of Science and Technology, University of Twente, Meander 229, PO Box 217, 7500 AE Enschede, The Netherlands.
PhotoCatalytic Synthesis Group, MESA+Institute for Nanotechnology, Faculty of Science and Technology, University of Twente, Meander 229, PO Box 217, 7500 AE Enschede, The Netherlands.
J Hazard Mater. 2015 Jan 23;282:208-15. doi: 10.1016/j.jhazmat.2014.05.087. Epub 2014 Jun 4.
The photocatalytic decomposition of cortisone 21-acetate (CA), a model compound for the commonly used steroid, cortisone, was studied. CA was photocatalytically decomposed in a slurry reactor with the initial rates between 0.11 and 0.46 mg L(-1)min(-1) at 10 mg L(-1) concentration, using the following heterogeneous photocatalysts in decreasing order of their catalytic activity: ZnO>Evonik TiO2 P25>Hombikat TiO2>WO3. Due to the lack of ZnO stability in aqueous solutions, TiO2 P25 was chosen for further experiments. The decomposition reaction was found to be pseudo-first order and the rate constant decreased as a function of increasing initial CA concentration. Changing the initial pH of the CA solution did not affect the reaction rate significantly. The decomposition reaction in the presence of the oxidizing sacrificial agent sodium persulfate showed an observed decomposition rate constant of 0.004 min(-1), lower than that obtained for TiO2 P25 (0.040 min(-1)). The highest photocatalytic degradation rate constant was obtained combining both TiO2 P25 and S2O8(2-) (0.071 min(-1)) showing a synergistic effect. No reactive intermediates were detected using LC-MS showing fast photocatalytic decomposition kinetics of CA.
皮质酮 21- 醋酸酯（CA）是一种常用的皮质激素的模型化合物，其光催化分解得到了研究。在初始浓度为 10 mg/L 时，在浆态反应器中用以下非均相光催化剂以降序的催化活性对 CA 进行光催化分解：ZnO>Evonik TiO2 P25>Hombikat TiO2>WO3。由于 ZnO 在水溶液中稳定性差，因此选择 TiO2 P25 进行进一步实验。发现分解反应为准一级反应，并且随着初始 CA 浓度的增加，速率常数减小。改变 CA 溶液的初始 pH 值对反应速率的影响不显著。在氧化牺牲剂过硫酸钠存在下的分解反应显示出观察到的分解速率常数为 0.004 min(-1)，低于 TiO2 P25（0.040 min(-1)）的值。当同时使用 TiO2 P25 和 S2O8(2-)时，获得了最高的光催化降解速率常数（0.071 min(-1)），表现出协同效应。使用 LC-MS 未检测到反应中间体，表明 CA 的光催化分解动力学很快。
