Department of Chemistry, Biochemistry and Environmental Protection, Faculty of Sciences, University of Novi Sad, Novi Sad, Serbia.
J Hazard Mater. 2011 Dec 30;198:123-32. doi: 10.1016/j.jhazmat.2011.10.017. Epub 2011 Oct 8.
This study investigates the efficiency of the photocatalytic degradation of metoprolol tartrate (MET), a widely used β(1)-blocker, in TiO(2) suspensions of Wackherr's "Oxyde de titane standard" and Degussa P25. The study encompasses transformation kinetics and efficiency, identification of intermediates and reaction pathways. In the investigated range of initial concentrations (0.01-0.1 mM), the photocatalytic degradation of MET in the first stage of the reaction followed approximately a pseudo-first order kinetics. The TiO(2) Wackherr induced a significantly faster MET degradation compared to TiO(2) Degussa P25 when relatively high substrate concentrations were used. By examining the effect of ethanol as a scavenger of hydroxyl radicals (OH), it was shown that the reaction with OH played the main role in the photocatalytic degradation of MET. After 240 min of irradiation the reaction intermediates were almost completely mineralized to CO(2) and H(2)O, while the nitrogen was predominantly present as NH(4)(+). Reaction intermediates were studied in detail and a number of them were identified using LC-MS/MS (ESI+), which allowed the proposal of a tentative pathway for the photocatalytic transformation of MET as a function of the TiO(2) specimen.
本研究考察了广泛应用于β(1)-阻滞剂的酒石酸美托洛尔（MET）在 Wackherr“标准二氧化钛”和 Degussa P25 悬浮液中的光催化降解效率。研究涵盖了转化动力学和效率、中间产物的鉴定和反应途径。在所研究的初始浓度范围内（0.01-0.1 mM），反应初期的 MET 光催化降解近似遵循准一级动力学。与 TiO2 Degussa P25 相比，当使用相对较高的底物浓度时，Wackherr 的 TiO2 诱导 MET 降解的速度明显更快。通过考察乙醇作为羟基自由基（OH）清除剂的作用，可以看出 OH 与 MET 的反应在光催化降解中起着主要作用。照射 240 分钟后，反应中间体几乎完全矿化为 CO2 和 H2O，而氮主要以 NH4+的形式存在。详细研究了反应中间体，并使用 LC-MS/MS（ESI+）对其中一些进行了鉴定，这使得可以根据 TiO2 标本提出 MET 光催化转化的一个暂定途径。
