151250-76-9Relevant articles and documents
Visible light-driven photocatalytic degradation of organic pollutants by a novel Ag3VO4/Ag2CO3 p–n heterojunction photocatalyst: Mechanistic insight and degradation pathways
Sun, Haibo,Qin, Pufeng,Wu, Zhibin,Liao, Chanjuan,Guo, Jiayin,Luo, Shuai,Chai, Youzheng
supporting information, (2020/04/28)
In the field of photocatalysis, the construction of a heterojunction system with efficient charge separation at the interface and charge transfer to increase the photocatalyst performance has gained considerable attention. In this study, the Ag3VO4/Ag2CO3 p–n heterojunction is first synthesized using a simple co-precipitation method. The composite photocatalyst with a p-n heterojunction has a strong internal electric field, and its strong driving force can effectively solve the problem of low separation and migration efficiency of photogenerated electron-hole pairs. The optimized Ag3VO4/Ag2CO3 composite can effectively degrade organic pollutants (rhodamine b (RhB), methylene blue (MB), levofloxacin (LVF), and tetracycline). More specifically, the Ag3VO4/Ag2CO3 photocatalyst with a 1:2 mass ratio (VC-12) can remove 97.8percent and 82percent of RhB and LVF within 30 and 60 min, respectively. The LVF degradation rate by VC-12 under visible light irradiation is more than 12.8 and 21.51 times higher than those of pure Ag3VO4 and Ag2CO3, respectively. The excellent photocatalytic activity of the Ag3VO4/Ag2CO3 hybrid system is mainly attributed to the internal electric field that forms in the Ag3VO4/Ag2CO3 p–n heterojunction system, the photogenerated electron hole pairs that separate and facilely migrate, and the specific surface area of VC-12 that is larger than that of the monomer. In addition, the degradation efficiency of VC-12 did not decline significantly after four cycles. In this study, the photocatalytic mechanism for Ag3VO4/Ag2CO3 photocatalysts is explored in detail based on the energy band analysis results, trapping experiment results, and electron spin resonance spectra. Finally, the LVF degradation products are analyzed by liquid chromatography–mass spectrometry, and the potential LVF degradation pathway is identified. The experiments performed in this research therefore lead to new motivation for the design and synthesis of highly efficient and widely applicable photocatalysts for environmental purification.
Nanopore enriched hollow carbon nitride nanospheres with extremely high visible-light photocatalytic activity in the degradation of aqueous contaminants of emerging concern
Yang, Yuxin,Hu, An,Wang, Xinyue,Meng, Jiaqi,Guo, Yihang,Huo, Mingxin,Zhu, Suiyi
, p. 355 - 365 (2019/01/28)
Construction of highly efficient hollow nanosphere photocatalytic systems has been strongly attracting the attention of researchers. In the present work, nanopore enriched hollow carbon nitride nanospheres (HCNNSs) with a smaller particle size (200 nm) and a thinner shell thickness (40 nm) are successfully fabricated by a silica-nanocasting strategy. Such unique structures possess many advantages such as large BET surface area (122 m2 g-1), high light-harvesting ability, fast charge separation and transfer efficiency, plentiful exposed active sites and enhanced oxidation ability of photogenerated holes (h+VB). Therefore, HCNNSs in smaller sizes (HCNNS-200) exhibit extremely excellent visible-light photocatalytic efficiency towards the degradation of contaminants of emerging concern, e.g. levofloxacin (LEVO), in comparison with bulk g-C3N4 and HCNNSs in larger sizes (HCNNS-500). And it takes less than 10 min to finish the degradation of LEVO. The experimental results including those from indirect chemical probing, electron spin resonance, ion chromatography and high performance liquid chromatography-mass spectrometry confirm that h+VB and O2- are the active species that are responsible for the mineralization of LEVO to NO3-, F-, H2O and CO2 under visible-light irradiation. Additionally, the degradation pathway of LEVO in the HCNNS-200 photocatalytic system is also proposed. It is expected that HCNNS-200 can be used as a promising photocatalyst for environmental remediation.
Preparation method of levofloxacin impurities
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Paragraph 0019; 0020, (2016/10/10)
The invention relates to the field of drug synthesis, in particular to a preparation method of levofloxacin impurities. The preparation method comprises the steps of carrying out reflux of levofloxacin carboxylic acid, N-methylethylenediamine hydrochloride and triethylamine in dimethylsulfoxide, and then obtaining a levofloxacin impurity I with high purity through washing column chromatography; and heating the impurity I and acetic anhydride in formic acid, and then obtaining a levofloxacin impurity II with high purity through washing column chromatography. The preparation method has the characteristics of short synthetic route, simple and convenient operation, high product purity of the obtained impurities and the like, and can be used for researches on levofloxacin impurity reference substances and so on.
Photodegradation products of levofloxacin in aqueous solution
Yoshida,Sato,Moroi
, p. 601 - 606 (2007/10/02)
The photodegradation of levofloxacin (DR-3355, CAS 100986-85-4), the S-(-)-isomer of ofloxacin, was investigated. Levofloxacin in aqueous solution was exposed to near ultraviolet light (peak wavelength 352 nm) for 16 h at room temperature. Nine degradation products (P-2-P-10) were isolated from the reaction mixture by preparative high performance liquid chromatography. The structures of these compounds were deduced from their NMR, MS, UV and IR spectra and optical rotations. The elucidated structures showed that all of these degradation products were analogues altered at the N-methylpiperazine moiety of levofloxacin.
