金属离子掺杂对TiO2光催化性能的影响

TiO₂光催化反应过程涉及光生电荷、电荷迁移、电荷在TiO₂表面的反应和溶液体相反应4个顺序相接并相互影响的步骤.在TiO₂中掺杂金属离子对以上4个步骤均有重要影响,合理的掺杂可有效地提高其光催化性能.本文综合了国内外此方面的最新研究成果,从提高TiO₂光催化性能和优化光催化反应的角度出发,在材料吸光能力、电荷扩散、表面反应、粒径和晶型等方面,全面地分析总结了金属离子掺杂的影响效果和规律性认识,并对TiO₂基光催化材料的金属离子掺杂改性研究的未来发展方向提出了建议.文中还简要介绍了相关的掺杂方法和材料表征手段.     

Synthesis, property characterization and photocatalytic activity of the novel composite polymer polyaniline/Bi2SnTiO7

A novel polyaniline/Bi(2)SnTiO(7 )composite polymer was synthesized by chemical oxidation in-situ polymerization method and sol-gel method for the first time. The structural properties of novel polyaniline/Bi(2)SnTiO(7) have been characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy and X-ray spectrometry. The lattice parameter of Bi(2)SnTiO(7) was found to be a = 10.52582(8) ?. The photocatalytic degradation of methylene blue was realized under visible light irradiation with the novel polyaniline/Bi(2)SnTiO(7) as catalyst. The results showed that novel polyaniline/Bi(2)SnTiO(7 )possessed higher catalytic activity compared with Bi(2)InTaO(7) or pure TiO(2) or N-doped TiO(2) for photocatalytic degradation of methylene blue under visible light irradiation. The photocatalytic degradation of methylene blue with the novel polyaniline/Bi(2)SnTiO(7) or N-doped TiO(2) as catalyst followed first-order reaction kinetics, and the first-order rate constant was 0.01504 or 0.00333 min(-1). After visible light irradiation for 220 minutes with novel polyaniline/Bi(2)SnTiO(7 )as catalyst, complete removal and mineralization of methylene blue was observed. The reduction of the total organic carbon, the formation of inorganic products, SO(4)2- and NO(3-), and the evolution of CO(2) revealed the continuous mineralization of methylene blue during the photocatalytic process. The possible photocatalytic degradation pathway of methylene blue was obtained under visible light irradiation.     

离子色谱法测定甘草提取物中草酸的含量

建立了用离子色谱测定甘草提取物中残留草酸含量的新方法。选用DionexIonPacAS11-HC阴离子分析柱(250mm×4mmi.d.),淋洗液为18mmol/LNaOH溶液,流速为1.0mL/min,抑制电导检测器检测。草酸色谱峰面积(Y)与浓度(X)在1.004～10.04mg/L内线性关系良好,线性回归方程为Y=0.1939X-0.0326,相关系数r=0.9999,检出限为0.012mg/L。样品回收率为96.8%～98.6%,相对标准偏差为0.78%。该方法简便、快速。     

Separation and quantitative determination of sesquiterpene lactones in Lindera aggregata (Wu‐yao) by ultra‐performance LC‐MS/MS

An ultra‐performance LC in combination with MS/MS method was established to evaluate the quality of Wu‐yao (the dried root of Lindera aggregata (Sims) Kosterm. (Lauraceae)) through simultaneous quantitation of five sesquiterpene lactones, linderagalactone D ( 1 ), linderagalactone C ( 2 ), hydroylindestenolide ( 3 ), neolinderalactone ( 4 ) and linderane ( 5 ). All compounds were separated on a Waters Acquity ultra‐performance LC HSS T3 column (2.1 mm×100 mm, 1.8 μm particle size) with linear gradient elution of acetonitrile and 0.1% formic acid. An ESI interface in the positive mode was employed prior to MS detection. All the compounds showed good linearity (R²≥0.9992). The recoveries, measured at three concentration levels, varied from 97.3 to 103.4% with RSDs <4.8%. The simple, rapid and reliable method was successfully applied to quantify the five components in 13 samples of Wu‐yao from different areas.     

A rapid method with ultra‐high‐performance liquid chromatography–tandem mass spectrometry for simultaneous determination of five type B trichothecenes in traditional Chinese medicines

A speedy and selective ultra‐HPLC‐MS/MS method for simultaneous determination of deoxynivalenol (DON), 3‐acetyldeoxynivalenol (3‐ADON), 15‐ADON, nivalenol and fusarenon X in traditional Chinese medicines (TCMs) was developed. The method was based on one‐step sample cleanup using reliable homemade cleanup cartridges. A linear gradient mobile‐phase system, consisting of water containing 0.2% aqueous ammonia and acetonitrile/methanol (90:10, v/v) at a flow rate of 0.4 mL/min, and an Acquity UPLC HSS T3 column (100 mm×2.1 mm, 1.8 μm) were employed to obtain the best resolution of the target analytes. [¹³C₁₅]–DON was used as the internal standard to accomplish as accurate as possible quantitation. The established method was further validated by determining the linearity (R²≥0.9990), sensitivity (LOQ, 0.29–0.99 μg/kg), recovery (88.5–119.5%) and precision (RSD≤15.8%). It was shown to be a suitable method for simultaneous determination of DON, 3‐ADON, 15‐ADON, nivalenol and fusarenon X in various TCM matrices. The utility and practical impact of the method was demonstrated using different TCM samples.     

Characterization and thermal analysis of thiourea and bismuth trichloride complex

A complex of thiourea and bismuth trichloride has been synthesized. Its composition is Bi₃Cl₉[SC(NH₂)₂]₇. Crystallographic data are a = 7.141(2) Å, b = 8.820(3) Å, c = 16.365(5) Å, α = 99.389(4)°, β = 95.422(4)°, γ = 106.177(4)°, triclinic system. There are the mononuclear anion [BiCl₅SC(NH₂)₂]^2? and the dinuclear cation {Bi₂Cl₄[SC(NH₂)₂]₆}²⁺ with the Bi–Cl–Bi bridge bonds in the complex. The electric conductance of the absolute methanol solution contained the complex indicates that the complex is an ionic compound. Raman spectra indicate that the bismuth ion is coordinated by the sulfur atoms of the thiourea. The thermal analysis verifies the structure of complex. The TG–MASS curves show the structure rearrangement in the complex at about 118 °C. The DSC curves and calculation means that the structure rearrangement is irreversible.     

Role of the preparation procedure in the formation of spherical and monodisperse surfactant/polyelectrolyte complexes

Complexes formed by a double-tail cationic surfactant, didodecyldimethyl ammonium bromide, and an anionic polyelectrolyte, an alternating copolymer of poly(styrene-alt-maleic acid) in its sodium salt form, were investigated with respect to variation in the charge ratio (x) between the polyelectrolyte negative charges and the surfactant positive charges. The morphology and microstructure of the complexes were studied by light microscopy and small-angle X-ray scattering for different preparation conditions. Independent of the sample preparation procedure and the charge ratio x, the X-ray results show that the microscopic structure of the complexes is a condensed lamellar phase. By contrast, the morphology of the complexes changes dramatically with the preparation procedure. The complexes formed by mixing a surfactant solution and a polyelectrolyte solution strongly depend on x and are always extremely heterogeneous in size and shape. Surprisingly, we show that, when the two solutions interdiffuse slowly, spherical complexes of micrometric and rather uniform size are systematically obtained, independently on the initial relative amount of surfactant and polyelectrolyte. The mechanism for the formation of these peculiar complexes is discussed.     

Synthesis of CuS@CoS2 Double‐Shelled Nanoboxes with Enhanced Sodium Storage Properties

Metal sulfides have received considerable attention for efficient sodium storage owing to their high capacity and decent redox reversibility. However, the poor rate capability and fast capacity decay greatly hinder their practical application in sodium‐ion batteries. Herein, an elegant multi‐step templating strategy has been developed to rationally synthesize hierarchical double‐shelled nanoboxes with the CoS₂ nanosheet‐constructed outer shell supported on the CuS inner shell. Their structure and composition enable these hierarchical CuS@CoS₂ nanoboxes to show boosted electrochemical properties with high capacity, outstanding rate capability, and long cycle life.     

Low-temperature synthesis of allyl dimethylamine by selective heating under microwave irradiation used for water treatment

Low-temperature synthesis of allyl dimethylamine (ADA) by selective heating under microwave irradiation (MI) used for water treatment is investigated. The effect of MI, ultrasound irradiation (UI) and conventional heating on yield of ADA, reaction time and the flocculation efficiency of polydiallyl dimethylammunion chloride (PDADMAC) prepared form ADA were studied. The results show that by selective heating at low temperature, MI not only increases yield of ADA and reduces reaction time, but also greatly enhances the flocculation efficiency of PDADMAC.