PBA@POM Hybrids as Efficient Electrocatalysts for the Oxygen Evolution Reaction

To realize the effective conversion of renewable energy through water decomposition, efficient electrocatalysts for the oxygen evolution reaction (OER) are essential. In this article, PBA@POM was successfully prepared with a Prussian blue analogue (PBA) as the initial structure. A facile hydrothermal process is reported for obtaining PBA@POM by etching the cubic PBA with a strong Brønsted acid, H₃PMo₁₂O₄₀ (HPMo). The hollow cube structure not only exposes more active sites but also promotes electron transport, which results in excellent electrocatalytic activity for the OER. Compared with the PBA, which initially simply adhered to POM, the optimum PBA@POM hybrids display remarkably enhanced OER catalytic activity, with an almost constant overpotential of 440 mV at a current density of 10 mA cm^?2 and a small Tafel slope (23.45 mV dec^?1). The facilely prepared PBA@POM with good electrochemical activity and stability promises great potential for the OER.     

铬酸引发丙烯腈与苎麻纤维接枝共聚反应

棉、麻类织物通过与乙烯类单体接枝共聚可以提高染色性、皱折回复性、耐磨性、防污性等［‘j．纤维素接枝共聚物的合成始于50年代，目前研究最多的是乙烯类单体通过自由基活性中间体与纤维素进行接技共聚，但此法存在一个突出的问题是在接技共聚的同时生成大量均聚物．铬酸（下文用Cr’“表示）是公认的强氧化剂，据报道［’－‘j，它单独存在时并不能引发乙烯类单体聚合，如果用Cr‘”引发乙烯类单体与纤维素接技共聚，均聚物的生成量将会减少．本文以Cr’”为引发剂，将丙烯睛（AN）与艺麻纤维进行接技共聚，考查不同条件对接技率及均聚…     

Feasibility of a liquid-phase microextraction sample clean-up and liquid chromatographic/mass spectrometric screening method for selected anabolic steroid glucuronides in biological samples

Anabolic androgenic steroids (AAS) are metabolized extensively in the human body, resulting mainly in the formation of glucuronide conjugates. Current detection methods for AAS are based on gas chromatographic/mass spectrometric (GC/MS) analysis of the hydrolyzed steroid aglycones. These analyses require laborious sample preparation steps and are therefore time consuming. Our interest was to develop a rapid and straightforward method for intact steroid glucuronides in biological samples, using liquid-phase microextraction (LPME) sample clean-up and concentration method combined with liquid chromatographic/tandem mass spectrometric (LC/MS/MS) analysis. The applicability of LPME was optimized for 13 steroid glucuronides, and compared with conventional liquid-liquid extraction (LLE) and solid-phase extraction (SPE) procedures. An LC/MS/MS method was developed for the quantitative detection of AAS glucuronides, using a deuterium-labeled steroid glucuronide as the internal standard. LPME, owing to its high specificity, was shown to be better suited than conventional LLE and SPE for the clean-up of urinary AAS glucuronides. The LPME/LC/MS/MS method was fast and reliable, offering acceptable reproducibility and linearity with detection limits in the range 2-20 ng ml(-1) for most of the selected AAS glucuronides. The method was successfully applied to in vitro metabolic studies, and also tested with an authentic forensic urine sample. For a urine matrix the method still has some unsolved problems with specificity, which should be overcome before the method can be reliably used for doping analysis, but still offering additional and complementary data for current GC/MS analyses.     

Solid-Phase Microextraction Gas Chromatography for Determination of Some Organophosphorus Pesticides

A simple and rapid solid-phase microextraction (SPME) method is presented based on activated charcoal–PVC fiber for determination of some organophosphorus pesticides from aqueous samples in direct mode SPME. After optimization of the experimental variables affecting SPME of the target compounds from aqueous solutions, the proposed method was applied to determine pesticides in fruit juice. The analytes in this procedure were preconcentrated for 15 min on the SPME fiber and subsequently desorbed by heating the fiber at 200 °C for 5 min in the GC injection port. Separation was on a capillary column GC followed by flame ionization detection. Recoveries of the pesticides studied in aqueous samples ranged 42%–63% and repeatability for all analytes was < 9% for a single fiber. Fiber-to-fiber reproducibility was < 18%.     

Isolation of lysozyme from hen egg albumen using glass fiber-based cation-exchange membranes

In this study, porous glass fiber membranes were coated with monophenyl trimethoxysilane (MPh) and then sulphonated by chlorosulphonic acid to prepare the cation-exchange membranes with sulphonic acid groups. Different MPh-coating times were tested and the properties of the resulting membranes such as contact angle, FTIR spectrum, conductivity, and ion-exchange capacity were measured. It was found that the optimal MPh-coating time was 60 min and the related ion-exchange capacity was 49.5 μequiv./disc. The modified membrane under the optimal MPh-coating condition was adopted for lysozyme isolation. The results were compared with those for the commercial cation-exchange membrane with sulphonic acid groups (ICE 450 unsupported membrane). Although the prepared membrane exhibited less adsorption capacity than ICE 450 unsupported membrane in the batch lysozyme adsorption experiment, it showed lower non-specific binding ratio under higher salt concentration. In the flow process isolating lysozyme from hen egg albumen, the purification effectiveness obtained using the prepared cation-exchange membrane was superior to the ICE 450 unsupported membrane.     

Determination of organochlorine pesticides by gas chromatography with solid-phase microextraction

Summary A study of different extraction techniques for the determination of a selected group of organochlorine compounds in surface waters is presented. Comparison of liquid-liquid extraction (LLE) with solid-phase extraction (SPE) and solid-phase microextraction (SPME) with fibers of different polarity shows that SPME with a recently commercialised fiber of polydimethylsiloxane divinylbenzene allows these compounds to be determined in surface waters with good extraction efficiencies. Extraction time, effect of temperature, ionic strength and pH were optimised, allowing quantification in agricultural effluents in the range 1.0–60 ng·L⁻¹.     

The effect of fiber coating on the tensile properties of ionomer-based composites

Asbestos fibers, of the chrysotile variety, were coated with a thin polyamide film by an in situ polycondensation technique. Ionomer-based composites were prepared containing the so-modified asbestos fibers in a random in-plane orientation; results of testing the tensile properties of these asbestos/polyamide/ionomer composites are presented. Parameters investigated comprise the asbestos content in the composite and the polyamide content deposited on asbestos. A significant improvement in the tensile performance was established, especially at the intermediate polyamide content of 3.4 phr. The behavior is discussed in terms of possible interactions between the phases present in the composite material.     

Smith－Hieftje背景校正法空心阴极灯供电条件的选择

本文提出在原子吸收光谱测定中，采用Ｓｍｉｔｈ－Ｈｉｅｆｔｊｅ法校正背景时，空心阴极灯供电条件（即最佳宽窄脉冲电流）的选择依据和选择方法；并给出２４个常见元素的宽窄脉冲电流的选定结果。     

活性炭纤维电极电解法处理墨绿B染料废水

将铁丝缠绕在活性炭纤维(简称ACF)上制成电极,并在阴极鼓入空气,用电解生成的Fenton试剂处理墨绿B染料模拟废水.研究了电压、pH值、温度、空气流量、支持电解质的浓度等因素对染料脱色率的影响.结果表明,pH值越低,温度越高,处理效果越好,气流量的改变对于处理效果影响不大.室温时处理浓度为50mg·L-1的活性染料墨绿B,在实验电压为11V,中性条件下,无水硫酸钠的浓度为20g·L-1,通入空气流量为60L·min-1时,处理60min,色度去除率达到95%左右.55℃时,电解30min色度去除率就达到96%,60min时达到100%.     

ZrO2纳米粉末复合羊毛纤维研究

ＺｒＯ_２纳米粉末复合羊毛纤维研究陈代荣，樊悦朋（山东大学化学系济南２５０１００）关键词ＺｒＯ_２纳米粉末，羊毛纤维，复合纤维由陶瓷粉末和天然纤维形成的复合纤维的强度、织品的保暖性、抗起球性及防缩性能等均有所提高，报道较多的是微米级陶瓷粉末（粒径０．５...