钨酸铋对四环素光催化降解性能

采用水热法制备了钨酸铋催化剂,以空气为氧化剂,四环素为底物,考察了制备催化剂时溶液的酸度、降解反应时不同光源、光强度和催化剂量对钨酸铋的光催化降解四环素性能的影响.结果表明,当制备钨酸铋催化剂溶液的pH为1时,催化降解效果较好;当催化剂与四环素的物质的量之比为0.3∶1时,光照时间100 min,光催化降解率达66%;以钨酸铋为催化剂,太阳光光催化降解性能优于红外光和紫外光,太阳光强度越强,催化降解效果越好.     

煅烧温度对花朵状钨酸铋光催化活性的影响

钨酸铋在水相体系中能光催化降解有机污染物,而对于钨酸铋光催化活性影响因素的研究非常少.本文研究了煅烧温度对花朵状钨酸铋光催化活性的影响.以钨酸钠和硝酸铋为原料,在160°C下水热反应20 h,合成催化剂,并经不同温度煅烧3 h.用X射线衍射(XRD)、拉曼(Raman)光谱、紫外-可见漫反射吸收光谱(UVVis DRS)和荧光(PL)光谱表征样品.结果表明,这些样品具有十分相似的相组成和电子结构.然而,对于水中苯酚的降解,钨酸铋的光催化活性显示出了很大的差异.钨酸铋的光催化活性随着煅烧温度的升高,先上升后下降,最优煅烧温度为350°C,并且不受样品比表面积大小的影响.这些样品的活性差异主要归结于钨酸铋的结晶度、吸光性和表面缺陷对其光生载流子分离效率的综合影响.     

四环素类抗生素药物的发现、发展与合成:源于天然产物,用于人类健康

四环素类抗生素是一类广谱抗生素,广泛应用于治疗由革兰阳性和阴性细菌、支原体、衣原体和立克次氏体感染所引起的疾病.四环素类抗生素药物由ABCD四个六元并环骨架结构所构成.目前,人们主要通过发酵途径获得四环素类天然抗生素,再通过化学半合成的方式对其进行结构改造,其中A环取代方式固定,人们主要对D环作结构改造以获得临床药效更加优异的非天然新型四环素类抗生素药物.自1962年四环素Sancycline全合成工作以来,合成工作者们完成了多个四环素类抗生素药物的全合成,如近年通过发展新颖合成策略完成了四环素类抗生素药物Doxycycline的全合成;其后,人们通过全合成高效地完成了其他四环素类抗生素药物的合成和结构改造,加速了新型四环素类抗生素药物的研发与上市.本综述归纳总结了四环素类药物的发现和发展史,并介绍了其生物合成机制和针对病原菌的药物作用模式,详细介绍并比较了各种四环素类药物的半合成和全合成方式,将为研究者了解四环素抗生素及其结构类似药物的发现、发展和合成空间等起到有益作用.     

煅烧温度对花朵状钨酸铋光催化活性的影响（英文）

钨酸铋在水相体系中能光催化降解有机污染物,而对于钨酸铋光催化活性影响因素的研究非常少.本文研究了煅烧温度对花朵状钨酸铋光催化活性的影响.以钨酸钠和硝酸铋为原料,在160°C下水热反应20 h,合成催化剂,并经不同温度煅烧3 h.用X射线衍射(XRD)、拉曼(Raman)光谱、紫外-可见漫反射吸收光谱(UVVis DRS)和荧光(PL)光谱表征样品.结果表明,这些样品具有十分相似的相组成和电子结构.然而,对于水中苯酚的降解,钨酸铋的光催化活性显示出了很大的差异.钨酸铋的光催化活性随着煅烧温度的升高,先上升后下降,最优煅烧温度为350°C,并且不受样品比表面积大小的影响.这些样品的活性差异主要归结于钨酸铋的结晶度、吸光性和表面缺陷对其光生载流子分离效率的综合影响.     

基于钨(钼)酸铋半导体复合材料的合成及其在光催化降解中的应用

由于全球的工农业的迅速发展,水污染已成为人类所面临的最大危机。基于半导体光催化法是治理水污染的绿色技术之一,能够有效地降解和去除水中的污染物。在众多光催化材料中,金属氧化物半导体由于其具有低毒性、高稳定性和对水溶液中化学腐蚀的较高的抵抗力等优点,而被科学家们广泛地研究和应用。其中,三元组分的金属氧化物因其具有较窄的禁带宽度和可见光响应性质,在光催化降解领域上的能力已经超过其他的金属化合物。本文系统地介绍了两种典型的三元金属氧化物——钨酸铋和钼酸铋,围绕着基于钨酸铋和钼酸铋的复合型催化剂的制备和在光催化降解废水处理领域中的应用以及发展进行了综述,提出了目前关于钨酸铋和钼酸铋的复合材料的设计、机理研究和改性修饰方法中的所存在的主要问题,并对未来的发展趋势进行了展望。     

含氧空位缺陷钨酸铋光催化产氢性能研究

新型半导体光催化剂钨酸铋是目前研究广泛的光催化剂,但因其电子空穴对易复合的问题,限制了光催化产氢性能。为解决这一问题,采用锂-乙二胺溶液在钨酸铋表面构筑可控氧空位缺陷和金属缺陷。通过材料表征对比了钨酸铋经锂-乙二胺处理前后的变化,并对两者进行了产氢速率测试。钨酸铋在经过锂-乙二胺处理过后产生了氧空位缺陷和降价的金属中心,材料颜色从原先的黄白色转变为黄棕色,增强了光吸收能力。颗粒的主体结构以及物质成分并未发生变化,仍保持花球状颗粒结构,但处理后钨酸铋颗粒表面原先的光滑的片状结构变得粗糙,且方形纳米薄片锋利边缘变光滑,提高了光催化反应面积。这些变化使锂-乙二胺处理后的钨酸铋光催化产氢性能相比未处理之前得到了一定的提升。     

HPLC-ESIMS/MS对动物组织中痕量四环素类抗生素的同时测定

四环素类抗生素属于广谱抗菌药物,广泛应用于食用动物的疾病预防和治疗.由于食品中痕量残留的四环素类抗生素可使人体正常的肠道菌群平衡遭到破坏,造成二重感染,导致中毒性胃肠炎,并对肝脏有一定的损害,甚至有致癌作用[1],因此严格监控食品中四环素类抗生素的残留量十分重要.     

高级氧化和可见光照射协同作用下Bi2WO6对有机污染物降解的催化活性增强(英文)

随着工业化社会的不断发展,环境问题日益严重。尤其是工业废水问题一直是催化降解领域的研究热点。光催化与高级氧化工艺(AOPs)耦合技术因为具有高效、无选择性、处理条件温和等特点,被认为是一种高效的有机污染物降解技术。本文以十六烷基三甲基溴化铵(CTAB)表面活性剂作为模板,采用简单的水热法制备了钨酸铋(Bi₂WO₆)纳米花。通过X射线衍射(XRD)、傅里叶红外光谱(FTIR)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线光电子能谱(XPS)和紫外-可见漫反射光谱(DRS)技术对其微观形貌、晶相、表面化学元素状态和光学性质进行了表征。为了研究钨酸铋(Bi₂WO₆)纳米花的催化性能,在不同催化体系下降解有机污染物罗丹明B (Rh B),实验发现,于vis/过硫酸盐(PMS)/Bi₂WO₆体系下,40 min内对Rh B的去除率高达96.39%,明显优于PMS/Bi₂WO₆ (40 min内去除率为38.7...     

Ni电极电化学流通池检测四环素类药品的研究

比较Au、GC和Ni电极对四环素的电化学响应,讨论了纯Ni电极对四环素的电催化氧化特性,提出以纯Ni为工作电极的电化学流通池,优化结构,建立了测定四环素类抗生素的电化学流通池安培检测法.该方法对四环素、土霉素和强力霉素都有较高的响应灵敏度,线性范围0.1～15mg/L.最低检出限分别为35、45和43μg/L.用此方法可以直接测定四环素类药品的含量.     

磷钨酸/SiO2负载化光催化剂的制备与表征

以溶胶–凝胶法合成的SiO2作载体,固载磷钨酸制得负载化磷钨酸光催化剂,用XRD、FT-IR、UV-Vis-DRS等方法表征了催化剂的理化性能。结果表明,所制备的负载化磷钨酸催化剂对甲基橙的光催化降解反应具有较好的催化性能。     

Novel Bi2WO6‐coupled Fe3O4 Magnetic Photocatalysts: Preparation,Characterization and Photodegradation of Tetracycline Hydrochloride

Novel Bi₂WO₆‐coupled Fe₃O₄ magnetic photocatalysts with excellent and stable photocatalytic activity for degrading tetracycline hydrochloride and RhB were successfully synthesized via a facile solvothermal route. Through the characterization of the as‐prepared magnetic photocatalysts by X‐ray diffractometry, scanning electron microscopy, transmission electron microscopy, X‐ray photoelectron spectroscopy, UV–Vis diffuse reflectance spectra, it was found that the as‐prepared magnetic photocatalysts were synthesized by the coupling of Bi₂WO₆ and Fe₃O₄, and introduction of appropriated Fe₃O₄ can improve nanospheres morphology and visible‐light response. Among them, BFe2 (0.16% Fe₃O₄) exhibited the best photocatalytic activity for degradation of tetracycline hydrochloride (TCH), reaching 81.53% after 90 min. Meanwhile, the as‐prepared magnetic photocatalysts showed great separation and recycle property. Moreover, the results of electrochemical impedance spectroscopy demonstrated that the well conductivity of Fe₃O₄ can promote photogenerated charge carriers transfer and inhibit recombination of electron–hole pairs, so that Bi₂WO₆/Fe₃O₄ exhibited enhanced photocatalytic activity on degradation of TCH and RhB. Hence, this work provides a principle method to synthesize Bi₂WO₆/Fe₃O₄ with excellent photocatalytic performance for actual application, in addition, it showed that introduction of Fe₃O₄ not only can provide magnetism, but also can enhance photocatalytic activity of Bi₂WO₆/Fe₃O₄ magnetic photocatalysts.     

Ag/Bi2WO6复合材料的制备及光催化性能

采用一步水热合成法制得花球状Bi_2WO_6和Ag/Bi_2WO_6光催化剂,借助X射线衍射(XRD)、场发射扫描电子显微镜(FES-EM)、透射电子显微镜(TEM)、X射线光电子能谱分析(XPS)、紫外-可见分光光度法(UV-Vis)等手段对样品进行结构性能表征。模拟日光的条件下,以甲基橙(MO)为降解物,对Bi_2WO_6和Ag/Bi_2WO_6的催化活性和机理进行研究。结果表明,相对Bi_2WO_6,相同条件下Ag/Bi_2WO_6对MO具有更佳的降解效果,当Ag掺杂量为1%(n/n)时,其降解率(180 min)可达到91.4%,同时一次回收样降解率也达到81%。此外,也对Ag/Bi_2WO_6复合材料的降解机理做了初步探究。     

三维花状Bi2WO6/BiOBr异质结的制备及对多种染料的降解性能

利用水热法以十二烷基二甲基溴化铵(DDAB)和十六烷基三甲基溴化铵(CTAB)为结构导向剂以及溴源,成功地制备了三维花状Bi₂WO₆/BiOBr异质结。通过X射线粉末衍射、扫描电镜、透射电镜、紫外可见漫反射光谱、光电流、Nyquist曲线和电子顺磁共振分别对样品的结构、形貌、组成和光电化学性能进行了表征。结果表明,20~30 nm的BiOBr纳米粒子均匀地附着在Bi₂WO₆薄片上形成三维花状结构。Bi₂WO₆/BiOBr与纯Bi₂WO₆相比,扩展了可见光的响应范围,且提高了催化剂光生电子与空穴的分离效率。光降解实验表明w_DDAB/w_CTAB=2.6时Bi₂WO₆/BiOBr的光催化性能最优。在300 W氙灯(波长>420 nm)可见光照射下,其在降解罗丹明B中表现出最高的反应速率常数(0.0997 min^-1),分别约为Bi₂WO₆(0.0376 min^-1)和BT?4(0.0523 min^-1,w_DDAB/w_CTAB=3.9)的2.7倍和1.9倍,且6个循环后活性依然没有明显衰减。Bi₂WO₆/BiOBr异质结还可以无选择性地降解其他类型的有机染料,如亚甲基蓝、孔雀石绿和甲基橙。最后,基于活性物种捕获实验和Mulliken原子电负性理论计算结果,提出了Bi₂WO₆/BiOBr异质结的光降解机理。     

Construction of NH2-MIL-125(Ti) nanoplates modified Bi2WO6 microspheres with boosted visible-light photocatalytic activity

Photoactive metal–organic frameworks (MOFs) have proven to be a promising porous material in the field of catalysis. Controllable integration of these MOFs with inorganic semiconductor materials may endow new multifunctional hybrid materials with preferable photocatalytic properties. In this research, NH₂-MIL-125(Ti) nanoplates modified Bi₂WO₆ microspheres was prepared via a simple solvothermal method. The photocatalytic behaviors of the acquired catalysts was evaluated via the degradation of tetracycline hydrochloride (TC) under visible light. The experimental results showed that NH₂-MIL-125(Ti)/Bi₂WO₆ composites display higher photocatalytic activity than that of single Bi₂WO₆, and the ideal incorporation amount of NH₂-MIL-125(Ti) was around 5 wt%. The steady state fluorescence spectrum, transient photocurrents and electrochemical impedance spectroscopy verified that the introduction of NH₂-MIL-125(Ti) could accelerate the separation and transfer of photogenerated carriers and thus improve the photocatalytic activity of Bi₂WO₆. The photocatalytic mechanism was explored in detail. This work extends the knowledge of integrating MOFs with traditional photocatalysts to form new composite materials in the area of environmental purification.

     

Z型异质结Cu2O/Bi2MoO6的构建及光催化降解性能

通过水热法制备出一系列Z型异质结Cu₂O/Bi₂MoO₆新型光催化剂。采用扫描电子显微镜、粉末X射线衍射、红外光谱、紫外可见吸收光谱等表征手段研究了催化剂的形貌、结构性质和光电化学性质,并以四环素(TC)为降解目标污染物,进一步探究了其催化效率。实验结果表明,Cu₂O的加入提高了复合催化剂的光催化性能,其中20% Cu₂O/Bi₂MoO₆复合催化剂(Cu₂O和Bi₂MoO₆的质量比为20%)降解效果最好,100 min内可降解95%的TC。Cu₂O与Bi₂MoO₆之间的协同作用使其可以吸收更多的可见光,所构建的Z型异质结改变了电子转移途径,提高了电子与空穴的分离效率,光催化活性显著提高。通过自由基捕获实验和能带结构,分析了Z型异质结Cu₂O/Bi₂MoO₆复合催化剂光催化降解TC可能的机理。     

Flower-like Bi2WO6/ZnO composite with excellent photocatalytic capability under visible light irradiation

The photocatalytic ability of ZnO is improved through the addition of flower-like Bi₂WO₆ to prepare a Bi₂WO₆/ZnO composite with visible light activity. The composite is characterized by X-ray diffraction, transmission electron microscopy, scanning electron microscopy with UV–vis diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy and N₂ adsorption-desorption isotherms. After modification, the band gap energy of Bi₂WO₆/ZnO is reduced from 3.2 eV for ZnO to 2.6 eV. Under visible light irradiation, the Bi₂WO₆/ZnO composite shows an excellent photocatalytic activity for degrading methylene blue (MB) and tetracycline. The photo-degradation efficiencies of (0.3:1) Bi₂WO₆/ZnO for MB and tetracycline are approximately 246 and 4500 times higher than those of bare ZnO, respectively, and correspondingly, the photo-degradation rates for the two pollutants are approximately 120 and 200 times higher than those with bare ZnO, respectively. Moreover, the photocatalyst of (0.3:1) Bi₂WO₆/ZnO exhibits a higher transient photocurrent density of approximately 4.5 μA compared with those of bare Bi₂WO₆ and ZnO nanoparticles. The successful recombination of Bi₂WO₆ and ZnO enhances the photocatalytic activity and reduces the band gap energy of ZnO, which can be attributed to the effective separation of electron–hole pairs. Active species trapping experiments display that [O₂]^? is the major species involved during photocatalysis rather than ?OH and h⁺. This study provides insight into designing a meaningful visible-light-driven photocatalyst for environmental remediation.     

CeO2/Bi2WO6 Heterostructured Microsphere with Excellent Visible‐light‐driven Photocatalytic Performance for Degradation of Tetracycline Hydrochloride

CeO₂/Bi₂WO₆ heterostructured microsphere with excellent and stable photocatalytic activity for degradation tetracyclines was successfully synthesized via a facile solvothermal route. The photocatalytic experiments indicated that CeO₂/Bi₂WO₆ heterostructured microspheres exhibited enhanced photocatalytic activity compared to pure Bi₂WO₆ in both the degradation of tetracycline hydrochloride (TCH) and rhodamine B (RhB) under visible‐light irradiation. The 1CeO₂/2Bi₂WO₆ exhibited the best photocatalytic activity for degradation of TCH, reaching 91% after 60 min reaction. The results suggested that the particular morphological conformation of the microspheres resulted in smaller size and more uniform morphology so as to increase the specific surface area. Meanwhile, the heterojunction was formed by coupling CeO₂ and Bi₂WO₆ in the as‐prepared microspheres, so that the separation efficiency of photogenerated electrons and holes was dramatically improved and the lifetimes of charge carriers were prolonged. Hence, introduction of CeO₂ could significantly enhance the photocatalytic activity of CeO₂/Bi₂WO₆ heterostructured microspheres and facilitate the degradation of TCH. This work provided not only a principle method to synthesize CeO₂/Bi₂WO₆ with the excellent photocatalytic performance for actual produce, but also a excellent property of the photocatalyst for potential application in photocatalytic treatment of tetracyclines wastewater from pharmaceutical factory.     

粉煤灰漂珠负载Bi2WO6复合材料的制备及光催化性能研究

以工业固体废弃物粉煤灰漂珠(fly ash cenospheres,FACs)为载体,采用水热法制备了新颖的漂珠负载Bi2WO6复合材料(Bi2WO6/FACs),通过X射线衍射(XRD),扫描电子显微镜(SEM),X-射线光电子能谱(XPS),和紫外-可见漫反射光谱(DRS)技术对其进行了表征。XRD数据显示了正交相Bi2WO6的特征衍射峰。DRS结果证实了引入FACs后Bi2WO6对可见光的吸收增强。在可见光的照射下,以亚甲基蓝溶液的光催化降解评价了Bi2WO6/FACs复合材料的光催化性能。结果表明:Bi2WO6/FACs的光催化性能优于纯Bi2WO6的,其一级反应速率常数(k)为后者的2.4倍。尤其是由于漂珠质轻中空的特性,Bi2WO6/FACS复合光催化剂可长时间漂浮于水面,既能充分吸收光能,又有利于催化剂的回收和重复利用。     

粉煤灰漂珠负载Bi2WO6复合材料的制备及光催化性能研究

以工业固体废弃物粉煤灰漂珠(fly ash cenospheres, FACs)为载体, 采用水热法制备了新颖的漂珠负载Bi₂WO₆复合材料(Bi₂WO₆/FACs), 通过X射线衍射(XRD), 扫描电子显微镜(SEM), X-射线光电子能谱(XPS), 和紫外-可见漫反射光谱(DRS)技术对其进行了表征。XRD数据显示了正交相Bi₂WO₆的特征衍射峰。DRS结果证实了引入FACs后Bi₂WO₆对可见光的吸收增强。在可见光的照射下, 以亚甲基蓝溶液的光催化降解评价了Bi₂WO₆/FACs复合材料的光催化性能。结果表明：Bi₂WO₆/FACs的光催化性能优于纯Bi₂WO₆的, 其一级反应速率常数(k)为后者的2.4倍。尤其是由于漂珠质轻中空的特性, Bi₂WO₆/FACS复合光催化剂可长时间漂浮于水面, 既能充分吸收光能, 又有利于催化剂的回收和重复利用。     

WO_3/Bi_(12)SiO_(20)光催化降解气相苯

用气液反应法和化学溶液分解技术(CSD)分别制备了WO3和Bi12SiO20粉末,并将二者耦合,合成出WO3/Bi12SiO20复合光催化剂.以气相苯的降解为探针反应,考查了催化剂的光催化活性.结果表明:耦合后的WO3/Bi12SiO20催化剂的催化活性显著提高,其中30%(w)WO3/Bi12SiO20在紫外光下对苯的降解率明显优于P-25,而且催化剂具有一定的可见光响应能力.采用X射线衍射(XRD)、扫描电子显微镜(SEM)、X射线光电子能谱(XPS)、N2吸附-脱附(BET)和紫外-可见漫反射(UV-VisDRS)等手段对催化剂进行了表征.结果表明:WO3与Bi12SiO20之间存在良好的能带协同作用.WO3与Bi12SiO20耦合后,催化剂的光响应范围拓宽,光生电子和空穴能有效地分离,光生电子和空穴产生速率增大,所以催化剂活性提高.