One-pot synthesis of peony-like Bi2S3/BiVO4(040) with high photocatalytic activity for glyphosate degradation under visible light irradiation

In this work, samples consisting of BiVO₄ with exposed (040) facets coupled with Bi₂S₃ (Bi₂S₃/BiVO₄) were prepared through a one-pot hydrothermal method, using ethylenediaminetetraacetic acid as directing agent and L-cysteine as sulfur source and soft template. X-ray diffraction, field emission scanning electron microscopy, and high-resolution transmission electron microscopy measurements indicated that the Bi₂S₃ content had a significant influence on the growth of (040) and (121) facets as well as on the morphology of the Bi₂S₃/BiVO₄ samples. When the Bi₂S₃ content reached 1 mmol, the Bi₂S₃/BiVO₄ samples exhibited a peony-like morphology. The results of transient photocurrent tests and electrochemical impedance spectroscopy measurements confirmed that a more effective charge separation and a faster interfacial charge transfer occurred in Bi₂S₃/BiVO₄ than BiVO₄. The enhanced photocatalytic activity of the Bi₂S₃/BiVO₄ samples could be attributed to the improved absorption capability in the visible light region and the enhanced electron-hole pair separation efficiency due to the formation of the Bi₂S₃/BiVO₄ heterostructure. In addition, the Bi₂S₃/BiVO₄ samples showed relative stability and reusability. The simple method presented in this work could be used to fabricate composite photocatalysts with high activity for different applications, such as photocatalytic degradation of organic pollutants, photocatalytic splitting of water, and photocatalytic reduction of carbon dioxide.     

基于硅杂蒽类染料的荧光探针及其应用

近年来,荧光成像技术为人们研究活体细胞及组织内的化学生物学过程提供了有效的研究工具,可以无损、实时、原位地以高时空分辨率实现对目标物进行生物荧光成像与分析。荧光成像技术在生物学、环境监测、临床诊断和药物发现等诸多研究领域发挥着越来越重要的作用。生物荧光成像技术的最新进展对发展新型小分子荧光染料及探针提出了更高的要求。激发和发射波长位于近红外光区（600~900 nm）的荧光染料及探针由于具有光毒性低、生物分子自发荧光干扰小、光散射低、组织穿透能力强等优点,非常适合用于生物荧光成像领域。通过将罗丹明分子中O桥原子用Si代替,得到了一类新型的探针分子--硅杂蒽类荧光探针。这类染料分子在保留了氧杂蒽荧光染料优越的光学性质的同时,光谱发生明显红移,满足了近红外荧光检测的要求,具有良好的生物相容性。本文综述了近年来基于硅杂蒽及其衍生物荧光探针的合成及在金属离子、pH值、小分子、生物酶等检测方面的研究进展,并且简要阐述了基于硅杂蒽类探针分子的识别检测机理以及其在生物成像等方面的应用。     

Molecularly imprinted polymers on the surface of silica microspheres via sol‐gel method for the selective extraction of streptomycin in aqueous samples

Streptomycin‐imprinted silica microspheres were prepared by combining a surface molecular‐imprinting technique with the sol‐gel method. A mixture of tetrahydrofuran, ethanol, and water (6:1:1, v/v/v) was selected as dispersing solvent while 3‐aminopropyltriethoxysilane and triethoxyphenylsilane acted as functional monomers, and tetraethyl orthosilicate as a cross‐linker. Characterization of the molecularly imprinted polymers was conducted using scanning electron microscope and dynamic binding experiments. As compared to the nonimprinted polymers, the imprinted polymers exhibited a higher degree of saturated adsorption volume up to 26.3 mg/g, and better selectivity even in an aqueous solution with interfering compounds, including dihydrostreptomycin, neomycin, and tetracycline. The adsorption ability and selectivity were observed to be influenced by the mole ratio of 3‐aminopropyltriethoxysilane and triethoxyphenylsilane. Feasibility of the polymers to be used for actual application was also evaluated with spiked samples, indicating great potential for large‐scale applications. Moreover, the streptomycin‐imprinted polymers can be repeatedly used for 12 cycles without losing original performance, which is beneficial for commercial use.     

希土脯氨酸配合物的合成和性质研究

通过希土氯化物与L-脯氨酸反应,制得了四种新的希土脯氨酸固体配合物。其通式为:Ln(prol)Cl₃·nH₂O(Ln=Y、La、Sm和Er).用化学分析、电导测定、热重分析、差热分析、红外光谱和核磁共振氢谱,确定了产物的组成,讨论了金属-配体的化学键性质。     

离子交换-原子捕集-火焰原子吸收光谱法测定水中的超痕量镍

在文中所述条件下,镍的原子捕集灵敏度较常规法高320倍,即在离子交换法浓缩仅40倍的情况下,可使镍的测定灵敏度提高12800倍,从而成功实现了ppt级超痕量镍的测定。     

后处理对TiO_2纳米薄膜的表面结构和光催化活性的影响

半导体TiO2光催化材料对环境中各种污染物的明显去除效果已引起人们的广泛关注犤1～6犦。在普通钠钙玻璃表面涂制高光催化活性的TiO2纳米薄膜,制成环保建筑材料,不仅可以自洁玻璃表面,而且可以用于净化空气、处理废水等。但由于在热处理过程中玻璃基体内的Na+离子扩散到薄膜表面,形成光生电子和空穴的复合中心,使TiO2纳米薄膜的光催化活性大大降低犤7～10犦。为了减少玻璃中Na+离子对TiO2薄膜光催化活性的有害影响,Paz等犤8犦研究了将钠钙玻璃浸入酸溶液中,使玻璃表面的钠离子被酸中的氢离子置换出来;在玻璃表面形成SiO2凝胶层,以便阻…     

2-羟基-萘甲醛缩对甲氧基苯甲酰腙的合成与荧光性质研究

合成了2-羟基-萘甲醛缩对甲氧基苯甲酰腙,采用元素分析和红外光谱对该化合物结构进行了表征。详细研究了该化合物在固态、不同溶剂中和有锌离子存在下的荧光光谱,探讨了溶剂极性和锌离子的存在对其荧光光谱的影响。结果表明：该化合物的固体和溶液都有很强的荧光,溶剂对其荧光性质有较大的影响,其DMF溶液在485nm处发光最强。金属锌离子具有荧光增敏性。     

胶束电动毛细管色谱-电喷雾质谱联用法同时测定妇宁栓中的5种有效成分

应用胶束电动毛细管色谱-电喷雾电离质谱联用法同时测定了妇宁栓中的小檗碱、巴马汀、苦参碱、儿茶素和黄芩苷5种主要有效成分的含量。在未涂层石英毛细管柱(80 cm×50 μm)中,以40 mmol/L月桂酸-100 mmol/L氨水溶液(含25%的乙腈,pH 9.5)为缓冲液,分离电压为25.0 kV,各组分在16 min内得到完全分离。电喷雾质谱检测时采用50%异丙醇水溶液(含3 mmol/L乙酸)为鞘液。结果表明,小檗碱、巴马汀、苦参碱、儿茶素、黄芩苷的线性范围分别为0.03～15、0.05～15、0.2～250、1.5～300和2.0～500 mg/L,检出限分别为0.01、0.02、0.05、0.5、0.6 mg/L。5种组分的加标回收率为94.0%～104.0%,相对标准偏差(RSD)在0.3%～3.2%之间。该法简便、快速、准确,重现性好,可用于妇宁栓中小檗碱、巴马汀、苦参碱、儿茶素、黄芩苷含量的同时测定。     

大豆中二硝基苯胺类除草剂多残留的气相色谱法定量检测及质谱确证

建立以凝胶渗透色谱法（GPC）和固相萃取法（SPE）及气相色谱法（GC）联用技术测定大豆中10种二硝基苯胺类除草剂（氟乐灵、乙氟灵、环丙氟、氯乙氟灵、仲丁灵、异乐灵、二甲戊乐灵、二硝胺、氨基丙氟灵和磺乐灵）多残留检测方法。目标农药经正己烷饱和的乙腈提取，凝胶渗透色谱除去大豆中大部分油脂及色素，再经Florisil柱净化和富集，依次用6mL二氯甲烷和6mL二氯甲烷＋丙酮（99＋1）洗脱。目标农药采用电子捕获检测（GC／ECD），外标法定量，并经质谱（MS）确证。两个添加水平重复6次，回收率分别为74％～105％和59％～105％；相对标准偏差〈20％；检出限为1．8～7．6μg／kg；定量限为6～38μg/kg。     

大开口复合材料加筋壁板稳定性分析

运用大型有限元软件Patran/Nastran分析了大开口复合材料加筋壁板的稳定性,并对不同加筋方式下壁板屈曲特征值和屈曲模态图进行了比较。结果表明:补强提高了大开口复合材料壁板的稳定性,但往往无法达到很好的效果,需要通过加筋改善其稳定性;加筋复合材料壁板稳定性较原有模型有较大提高;加筋大开口复合材料壁板屈曲特征值随筋条距开口中心距离的增加而减小,其屈曲分界线均位于筋条布置处;纵筋大开口复合材料加筋壁板一阶屈曲特征值为2.13,而横筋只达到1.08;纵筋布置对复合材料壁板稳定性影响明显高于横筋布置,可在实际工程应用中适当增加纵筋的布置。