研究目的
The aim of this study is to comprehensively examine the effects of common anions (Cl-, SO4 2-, NO3 -, HCO3 -, and H2PO4 -), cations (Ca2+, Mg2+, and Fe3+), and HA on UV/TiO2 photocatalytic degradation of MNZ. In addition, the effect of the presence of glucose, one of the most common excipients for pharmaceuticals, was investigated. The transformation products (intermediates) formed during UV/TiO2 photocatalysis in the presence of the most notable matrix species were detected and identified using ultra-performance liquid chromatography–quadrupole time-of-flight mass spectrometry (UPLC-QTof/MS) and UPLC–tandem mass spectrometry (UPLC-MS/MS) instruments.
研究成果
The presence of water matrix components significantly influenced the degradation efficiency and pathways of MNZ by UV/TiO2 photocatalysis. Glucose enhanced degradation through side reactions, while HA and Fe3+ ions altered degradation pathways by activating charge transfer and competing with MNZ for light adsorption, respectively. H2PO4 - ions slowed down degradation without changing the pathways. These findings highlight the importance of considering water matrix components in the photocatalytic degradation of antibiotics.
研究不足
The study focused on the effects of specific water matrix components on the photocatalytic degradation of MNZ by UV/TiO2. The findings may not be directly applicable to other pollutants or under different experimental conditions. The presence of other unstudied components in real water bodies could also influence the degradation efficiency and pathways.
1：Experimental Design and Method Selection:
The study investigated the effects of various water matrix components on the photocatalytic degradation of MNZ by UV/TiO2. The methodology included the use of UPLC-QTof/MS and UPLC-MS/MS for identifying transformation products.
2：The methodology included the use of UPLC-QTof/MS and UPLC-MS/MS for identifying transformation products.
Sample Selection and Data Sources:
2. Sample Selection and Data Sources: MNZ solutions were prepared with different concentrations of anions, cations, HA, and glucose to study their effects on degradation efficiency and pathways.
3：List of Experimental Equipment and Materials:
A photoreactor under UV-C light irradiation, UV lamp (100 W, model HL100CH-5, Sen Lights Co.), Waters UPLC-QTof/MS and UPLC-MS/MS instruments, Degussa P25 TiO2, and various chemicals including MNZ, NaCl, NaNO3, NaHCO3, NaH2PO4, Na2SO4, CaCl2, MgCl2, FeCl3, glucose, and HA.
4：Experimental Procedures and Operational Workflow:
Experiments were carried out in a photoreactor under UV-C light irradiation. Each water matrix component was added to an MNZ solution, followed by the addition of TiO2. The solution was stirred in the dark for 30 min to reach adsorption equilibrium, then irradiated under UV light. Samples were taken at preset time intervals, filtered, and analyzed for MNZ concentration and transformation products.
5：The solution was stirred in the dark for 30 min to reach adsorption equilibrium, then irradiated under UV light. Samples were taken at preset time intervals, filtered, and analyzed for MNZ concentration and transformation products.
Data Analysis Methods:
5. Data Analysis Methods: The concentration of MNZ was determined by HPLC, and transformation products were identified by UPLC-QTof/MS and UPLC-MS/MS. The removal efficiency of MNZ was calculated based on initial and final concentrations.
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