LC/MS分析加替沙星的光降解产物

目的 分析加替沙星的光降解产物。方法 用液相色谱仪和液质联用仪进行分离和分析。结果 确证加替沙星在光照后有降解产物产生。结论 加替沙星应尽量避光使用 ,以保证产品的质量。

雌酮在铁(Ⅲ)-草酸盐配合物体系中的光降解

以125W高压汞灯为光源，研究了水中雌酮（E1）在铁（Ⅲ）-草酸盐体系中的光降解；考察了初始pH值、铁（Ⅲ）／草酸盐配比、E1初始浓度对E1光降解的影响。结果表明，铁（Ⅲ）／草酸盐体系能引发E1的光降解。在pH=3．5，Fe（Ⅲ）／Ox配比为10／120／zmol／L时，2mg／LE1光照160min可以降解59％。在pH3-6范围内，pH为3～4时E1降解效率最高；在2-10mg／L范围内，光降解效率随水溶液中E1初始浓度的增加而降低。

药物不良反应-光敏反应

药物光敏反应(photosensitivity)是病人在服用或局部使用某些药物后暴露于光源(通常为日光)产生的不良反应.包括光毒反应(phototoxic response)和光变态反应(photoallergic reaction).两类光敏反应的不同在于发生机理、皮疹的发生及临床表现, 光毒反应的发生率明显高于光变态反应[1].光敏反应在停药后通常具有迅速可逆性.

反相高效液相色谱法测定氯霉素及其相关物质

目的 HPL C法同时测定氯霉素、二醇物及氯霉素光降解产物 ,更好地监控氯霉素尤其是氯霉素溶液制剂的质量。方法 ODS色谱柱 (15 0 mm× 4 .6 mm,5 μm) ;流动相为 0 .15 %己烷磺酸钠溶液 (用 0 .1%冰HAc溶液调节 p H3.7) -乙腈 (75∶ 2 5 ) ;紫外检测。比较了文献报道的不同流动相系统对氯霉素及水解、光解产物分离的影响 ,同时考查研究了 p H、离子对种类、离子对浓度等因素对分离的影响。结果 含离子对流动相可以提高二醇物的保留时间 ;p H对氯霉素及二醇物色谱峰影响较小 ,但对氯霉素光降解物色谱峰影响较大。结论 确定了同时检测氯霉素、二醇物及氯霉素光降解产物含量变化的 HPL C系统 ,方法简便 ,分离效果好。

光降解在凋落物分解中的作用

近年来,越来越多的研究者认识到光降解可能在凋落物分解中发挥着重要作用。本文对光降解的作用机制,光降解在碳循环、养分循环中的作用,光降解与微生物分解的关系,以及影响光降解的因素进行了综述。光降解对凋落物分解过程同时具有正效应和负效应,正效应指光降解通过氧化有机质,或是改变凋落物自身理化性质使其更易淋溶和分解,负效应指高光辐射对分解者产生不利影响从而抑制微生物分解。在光降解过程中光化学矿化产生CO2是生态系统碳流失的主要机制。除紫外光外,可见光中的蓝、绿光波段也对凋落物的降解产生影响。光降解作用的大小受到水分状况、凋落物化学性质和凋落物的暴露面积的影响。最后,讨论了该领域有待深入研究的方向,指出今后应当重点对光降解研究方法,光降解与环境因子的交互作用,光降解作用的空间差异,光降解与微生物分解的相互关系及其作用强度进行研究。

Synthesis and highly efficient photocatalytic activity of mixed oxides derived from ZnNiAl layered double hydroxides

ZnO/NiO/ZnAl2O4 mixed-metal oxides were successfully synthesized through a hydrotalcite-like precursor route, in which appropriate amounts of metal salts solutions were mixed to obtain a new series of ZnNiAl layered double hydroxides（LDHs） as precursors, followed by calcination under different temperatures. The as-obtained samples were characterized by SEM, HRTEM, TEM, XRD, BET, TG-DTA, and UV-Vis spectra techniques. The photocatalytic activities of the samples were evaluated by degradation of methyl orange（MO） under the simulated sunlight irradiation. The effects of Zn/Ni/Al mole ratio and calcination temperature on the composition, morphology and photocatalytic activity of the samples were investigated in detail. The results indicated that compared with ZnNiAl-LDHs, the mixed-metal oxide showed superior photocatalytic performance for the degradation of MO. A maximum of 97.3% photocatalytic decoloration rate within 60 min was achieved from the LDH with the Zn/Ni/Al mole ratio of 2：1：1 and the calcination temperature of 500 ℃, which much exceeded that of Degussa P25 under the same conditions. The possible mechanism of photocatalytic degradation over ZnO/NiO/ZnAl2O4 was discussed.

Substrate-dependent photoreactivities of BiOBr nanoplates prepared at different pH values

In this study,we showed that BiO Br nanoplates prepared at different pH values have substratedependent photocatalytic activities under visible-light irradiation. The BiO Br nanoplates synthesized at pH 1（BOB-1） degraded salicylic acid more effectively than did those obtained at pH 3（BOB-3）,but the order of their photocatalytic activities in rhodamine B（RhB） degradation were reversed. Electrochemical Mott–Schottky and zeta-potential measurements showed that BOB-1 had a more positive valence band and lower surface charge,leading to superior photocatalytic activity in salicylic acid degradation under visible light. However,BOB-3 was more powerful in RhB degradation because larger numbers of superoxide radicals were generated via electron injection from the excited RhB to its more negative conduction band under visible-light irradiation; this was confirmed using active oxygen species measurements and electron spin resonance analysis. This study deepens our understanding of the origins of organic-pollutant-dependent photoreactivities of semiconductors,and will help in designing highly active photocatalysts for environmental remediation.

Photocatalytic Degradation of Water-Soluble Dyes by LaCoO_3

Pervoskite type oxides LaCoO 3 was prepared by citrate method with the granula of 20 nm-30 nm. With a fluorescent Hg lamp or sunlight as irradiator, the degradation experiments of various water soluble dyes were carried out in the suspension system of LaCoO 3 . The results show that the pervoskite type oxide LaCoO 3 has good photocatalytic activity.Studied by X ray photoelectron spectroscopy and photoacoustic spectra, its photocatalytic activity is found to be related with factors such as the d electron structure of ion Co 3+ ,Co—O binding energy and adsorbed oxygen on the surface etc.

Preparation of three-dimensional interconnected mesoporous anatase TiO_2-SiO_2 nanocomposites with high photocatalytic activities

In this article, we report the preparation of a three-dimensional（3D） interconnected mesoporous anatase TiO2-SiO2 nanocomposite. The nanocomposite was obtained by using an ordered two-dimensional（2D） hexagonal mesoporous anatase 70 TiO2-30 SiO2-950 nanocomposite（crystallized at 950 °C for 2 h） as a precursor, NaO H as an etchant of SiO2 via a ＂creating mesopores in the pore walls＂ approach. Our strategy adopts mild conditions of creating pores such as diluted NaO H solution, appropriate temperature and solid/liquid ratio, etc. aiming at ensuring the integrities of mesopores architecture and anatase nanocrystals. XRD, TEM and N2 sorption techniques have been used to systematically investigate the physico-chemical properties of the nanocomposites. The results show that the intrawall mesopores are highly dense and uniform（average pore size 3.6 nm）, and highly link the initial mesochannels in a 3D manner while retaining mesostructural integrity. There is no significant change to either crystallinity or size of the anatase nanocrystals before and after creating the intrawall mesopores. The photocatalytic degradation rates of rhodamine B（RhB, 0.303 min^–1） and methylene blue（MB, 0.757 min^–1） dyes on the resultant nanocomposite are very high, which are 5.1 and 5.3 times that of the precursor; even up to 16.5 and 24.1 times that of Degussa P25 photocatalyst, respectively. These results clearly demonstrate that the 3D interconnected mesopores structure plays an overwhelming role to the increments of activities. The 3D mesoporous anatase TiO2-SiO2 nanocomposite exhibits unexpected-high degradation activities to RhB and MB in the mesoporous metal oxide-based materials reported so far. Additionally, the nanocomposite is considerably stable and reusable. We believe that this method would pave the way for the preparation of other 3D highly interconnected mesoporous metal oxide-based materials with ultra-high performance.

Characterization of V_2O_5/MoO_3 composite photocatalysts prepared via electrospinning and their photodegradation activity for dimethyl phthalate

Vanadium pentoxide（V2O5）/molybdenum trioxide（MoO 3） composites with different molar ratios of vanadium（V） to molybdenum（Mo） were synthesized via a simple electrospinning technique. The photocatalytic activity of the composites were evaluated by their ability to photodegrade methylene blue and dimethyl phthalate（DMP） under visible-light irradiation. Compared with pure V2O5 and MoO 3,the V2O5/MoO 3 composites showed enhanced visible-light photocatalytic activity because of a V 3d impurity energy level and the formation of heterostructures at the interface between V2O5 and MoO 3. The optimal molar ratio of V to Mo in the V2O5/MoO 3 composites was found to be around 1/2. Furthermore,high-performance liquid chromatographic monitoring revealed that phthalic acid was the main intermediate in the photocatalytic degradation process of DMP.

Heterojunction between anodic TiO_2/g-C_3N_4 and cathodic WO_3/W nano-catalysts for coupled pollutant removal in a self-biased system

An anodic TiO2/g-C3N4 hetero-junction and cathodic WO3/W were used to build a self-sustained catalytic fuel cell system for oxidizing rhodamine B or triclosan and reducing NO3^--N to N2 simultaneously.The WO3 nano-catalyst was formed in situ by heating and oxidizing a tungsten wire in air.Cyclic voltammetry and current-time curves were used to characterize the electrochemical properties of the electrodes and system.Aeration and activation of molecular oxygen by self-biased TiO2/g-C3N4 led to the formation of reactive oxidizing species in the fuel cell.The mechanism of simultaneous anodic oxidation of pollutants and cathodic reduction of nitrate was proposed.The spontaneously formed circuit and tiny current were used simultaneously in treating two kinds of wastewater in the reactor chambers,even without light illumination or an external applied voltage.This new catalytic pollution control route can lower energy consumption and degrade many other kinds of pollutants.

Hydrogen producing water treatment through mesoporous TiO2 nanofibers with oriented nanocrystals

The development of well-defined TiO2 nanoarchitectures is a versatile strategy to achieve high-efficiency photocatalytic performance.In this study,mesoporous TiO2 nanofibers consisting of oriented nanocrystals were fabricated by a facile vapothermal-assisted topochemical transformation of preformed H-titanate nanobelts.The vapothermal temperature is crucial in tuning the microstructures and photocatalytic redox properties of the resulting mesoporous TiO2 nanofibers.The microstructures were characterized with XRD,TEM,XPS and nitrogen adsorption-desorption isotherms,etc.The photocatalytic activities were evaluated by photocatalytic oxidation of organic pollutant(Rhodamine B as an example)as well as photocatalytic reduction of water to generate hydrogen(H2).The nanofibers vapothermally treated at 150°C showed the highest photocatalytic activity in both oxidation and reduction reactions,2 times higher than that of P25.The oriented alignment and suitable mesoporosity in the resulting nanofiber architecture were crucial for enhancing photocatalytic performances.The oriented alignment of anisotropic anatase nanocrystals shall facilitate faster vectorial charge transportation along the nanofibers architecture.And,the suitable mesoporosity and high surface area would also effectively enhance the mass exchange during photocatalytic reactions.We also demonstrate that efficient energy-recovering photocatalytic water treatments could be accomplished by a cascading oxic-anoxic process where the dye is degraded in the oxic phase and hydrogen is generated in the successive anoxic phase.This study showcases a novel and facile method to fabricate mesoporous TiO2 nanofibers with high photocatalytic activity for both clean energy production and environmental purification.

Photocatalytic Degradation of Water-Soluble Dyes by LaCoO3

Pervoskite type oxides LaCoO 3 was prepared by citrate method with the granula of 20 nm-30 nm. With a fluorescent Hg lamp or sunlight as irradiator, the degradation experiments of various water soluble dyes were carried out in the suspension system of LaCoO 3 . The results show that the pervoskite type oxide LaCoO 3 has good photocatalytic activity.Studied by X ray photoelectron spectroscopy and photoacoustic spectra, its photocatalytic activity is found to be related with factors such as the d electron structure of ion Co 3+ ,Co—O binding energy and adsorbed oxygen on the surface etc.

Bifunctional S-scheme g-C3N4/Bi/BiVO4 hybrid photocatalysts toward artificial carbon cycling

Although both the aerobic photocatalytic oxidation of organic pollutants into CO2 and the anaerobic photocatalytic reduction of CO2 into solar fuels have been intensively studied,few efforts have been devoted to combining these carbon-involved photocatalytic oxidation-reduction processes together,by which an artificial photocatalytic carbon cycling process can be established.The key challenge lies in the exploitation of efficient bifunctional photocatalysts,capable of triggering both aerobic oxidation and anaerobic reduction reactions.In this work,a bifunctional ternary g-C3N4/Bi/BiVO4 hybrid photocatalyst is successfully constructed,which not only demonstrates superior aerobic photocatalytic oxidation performance in degrading an organic pollutant(using the dye,Rhodamine B as a model),but also exhibits impressive photocatalytic CO2 reduction performance under anaerobic conditions.Moreover,a direct conversion of Rhodamine B to solar fuels in a one-pot anaerobic reactor can be achieved with the as-prepared ternary g-C3N4/Bi/BiVO4 hybrid photocatalyst.The excellent bifunctional photocatalytic performance of the g-C3N4/Bi/BiVO4 photocatalyst is associated with the formation of efficient S-scheme hybrid junctions,which contribute to promoting the appropriate charge dynamics,and sustaining favorable charge potentials.The formation of the S-scheme heterojunction is supported by scavenger studies and density functional theory calculations.Moreover,the in-situ formed plasmonic metallic Bi nanoparticles in the S-scheme hybrid g-C3N4/Bi/BiVO4 photocatalyst enhances vectorial interfacial electron transfer.This novel bifunctional S-scheme g-C3N4/Bi/BiVO4 hybrid photocatalyst system provides new insights for the further development of an integrated aerobic-anaerobic reaction system for photocatalytic carbon cycling.

Autumn Photoproduction of Carbon Monoxide in Jiaozhou Bay, China

Carbon monoxide(CO) plays a significant role in global warming and atmospheric chemistry. Global oceans are net natural sources of atmospheric CO. CO at surface ocean is primarily produced from the photochemical degradation of chromophoric dissolved organic matter(CDOM). In this study, the effects of photobleaching, temperature and the origin(terrestrial or marine) of CDOM on the apparent quantum yields(AQY) of CO were studied for seawater samples collected from Jiaozhou Bay. Our results demonstrat that photobleaching, temperature and the origin of CDOM strongly affected the efficiency of CO photoproduction. The concentration, absorbance and fluorescence of CDOM exponentially decreased with increasing light dose. Terrestrial riverine organic matter could be more prone to photodegradation than the marine algae-derived one. The relationships between CO AQY and the dissolved organic carbon-specific absorption coefficient at 254 nm for the photobleaching study were nonlinear, whereas those of the original samples were strongly linear. This suggests that: 1) terrestrial riverine CDOM was more efficient than marine algae-derived CDOM for CO photoproduction; 2) aromatic and olefinic moieties of the CDOM pool were affected more strongly by degradation processes than by aliphatic ones. Water temperature and the origin of CDOM strongly affected the efficiency of CO photoproduction. The photoproduction rate of CO in autumn was estimated to be 31.98 μmol m-2 d-1 and the total DOC photomineralization was equivalent to 3.25%- 6.35% of primary production in Jiaozhou Bay. Our results indicate that CO photochemistry in coastal areas is important for oceanic carbon cycle.

Pharmacokinetics and Biodegradation of Chitosan in Rats

Chitosan, an excellent biomedical material, has received a widespread in vivo application. In contrast, its metabolism and distribution once being implanted were less documented. In this study, the pharmacokinetics and biodegradation of fluorescein isothiocyanate(FITC) labeled and muscle implantation administrated chitosan in rats were investigated with fluorescence spectrophotometry, histological assay and gel chromatography. After implantation, chitosan was degraded gradually during its distribution to diverse organs. Among the tested organs, liver and kidney were found to be the first two highest in chitosan content, which was followed by heart, brain and spleen. Urinary excretion was believed to be the major pathway of chitosan elimination, yet 80% of chitosan administered to rats was not trackable in their urine. This indicated that the majority of chitosan was degraded in tissues. In average, the molecular weight of the degradation products of chitosan in diverse organs and urine was found to be <65 k Da. This further confirmed the in vivo degradation of chitosan. Our findings provided new evidences for the intensive and safe application of chitosan as a biomedical material.

Vessel healings after stenting with different polymers in STEMI patients

Background Different stems implantation in ST-segmem elevation myocardial infarction （STEMI） patients may influence the long term prognosis by affecting vessel healings after stenting. The aim of this study was to evaluate the vessel healings after implantation of drug elming stems （DES） with biodegradable or durable polymer or of bare-metal stems （BMS） in patients with ache STEMI. Methods This study included 50 patients, who underwem follow up angiogram and optical coherence tomography （OCT） assessment about one year after percutaneous coronary intervemion （PCI） for STEMI. According to the initial stems types, these patients were classified to durable （n = 19） or biodegradable polymer sirolimus-eluting stems （n = 15）, or BMS （n = 16） groups. The conditions of stem struts coverage and malapposi- tion were analyzed with OCT technique. Results A total of 9003 struts were analyzed： 3299, 3202 and 2502 from durable or biodegradable polymer DES, or BMS, respectively. Strut coverage rate （89.0%, 94.9% and 99.3%, respectively）, malapposition presence （1.7%, 0.03% and 0 of struts, respectively） and average intimal thickness over struts （76 ± 12 μm, 161 ± 30 μm and 292 ± 29 μm, respectively） were significantly differem among different stent groups （all P 〈 0.001）. Conclusions Vessel healing status in STEMI patients is superior after implantation of biodegradable polymer DES than durable polymer DES, while both are inferior to BMS.

Design of metal-organic frameworks(MOFs)-based photocatalyst for solar fuel production and photo-degradation of pollutants

Metal organic frameworks(MOFs)is a research hotspot in the solar fuel production and photo-degradation of pollutants field due to high surface area,rich metal/organic species,large pore volume,and adjustability of structures and compositions.Therefore,in this review,we first summarized the design factors of photocatalytic materials based on MOF from the perspective of"star"MOF.The modification strategies of MOFs-based photocatalysts were discussed to improve its photocatalytic activity and specific applications were summarized as well,including photocatalytic CO_(2)reduction,photocatalytic water splitting and photo-degradation of pollutants.Finally,the advantages and disadvantages of MOFs-based photocatalysts were discussed,the current challenges were highlighted,and suggestions for future research directions were proposed.

PREPRARATION OF CoPcS/TiO_2/BEADS AND THEIR PHOTOCATALYTIC REACTIVITY FOR PHOTODEGRADATION OF VEGETABLE OIL FLOATING ON WATER

The paper introduces the preparation of floating TiO2/beads photocalyst attached to the hollow glass micro-beads surface by sol-gel technique using tetrabutyl titanate as material and the preparation of floating CoPcS/TiO2/beads by dip-coatig technique. The optimal factor of degradation of vegetable oil floating on water using CoPcS/TiO2/beads was studied. The result showed that the removal rate of vegetable oil floating on water can highly reach 90% at the optimal condition （acidity or neutrality, 375W medium-pressure mercury vapour lamp, illumination 2h-3h, lg CoPcS/TiO2/beads）. The photocatalytic removal efficiency causing by CoPcS/TiO2/beads was increased rapidly by adding a trace amount of H2O2.