Electrochemical Detection of Thioether‐Based Fluorosurfactants in Aqueous Film‐Forming Foam (AFFF)

Using cyclic voltammetry (CV) and impedance (IMP), we report a simple approach to detect new fluorosurfactant ingredient formulated in aqueous film‐forming foam (AFFF), specifically the thioether‐based one. First, we employ ion chromatography (IC) to identify all possible elements with the help of chemical oxidation and infrared spectrum (IR) to identify all possible functional groups. We thus propose a possible thioether‐based molecular structure of fluorosurfactant formulated in AFFF. By studying the self‐assembled monolayer (SAM) formed on gold (Au) surface via thio‐Au bond, we establish a relationship between the SAM density and the amount of the thioether‐based fluorosurfactant for the AFFF detection. Solid phase extraction (SPE) and nanoporous Au electrode are employed to enhance the sensitivity. Consequently, a detection limit of 10 ppb (v/v) has been achieved for AFFF‐spiked tap water sample.     

含有序孔洞的多孔氧化铝薄膜的弹性模量测量

高纯铝箔在特定的溶液下经过电化学阳极氧化腐蚀，可在其表面生成一层多孔的非晶氧化铝层，孔大致呈六方密排，孔径分布均匀。此类薄膜具有规则的纳米级孔径，大的比表面积，可用在微纳滤方面和纳米材料组装方面。然而，对于此类薄膜力学性能的研究较少，在一定程度上限制其功能的开发和应用。为了获得此类多孔膜的弹性常数，本文用鼓膜法结合散斑干涉实验方法、单轴拉伸结合双光束干涉法和多普勒测振仪三种方法测量氧化铝多孔膜的弹性模量，得到的宏观弹性模量基本相同，并对三种方法的优缺点进行了比较，分析了多孔氧化铝膜与块状氧化铝材料或致密氧化铝膜力学性能的差并。     

Hierarchically‐ordered electroactive silica‐polyaniline nanohybrid: A novel material with versatile properties

Poly(trimethoxy silylpropylaniline), a nanoporous (pore diameter of 2.4 nm), electroactive (stable reversible redox characteristics), electrochromic (yellow at ?0.10 V, blue green at +0.50 V, and dark green at +0.70 V), and pH‐sensitive, silica–polyaniline (PANI) hybrid material (designated as KGM‐1) has been synthesized in powder form by a simple one‐pot chemical synthesis as well as a “thin nanolayered film” by cyclic voltammetry. High‐resolution transmission image of KGM‐1 informs that the particles are spherical, with diameters in the range of 0.5–1.5 μm. X‐ray diffraction pattern of pristine KGM‐1 confirms the combined presence of ordered silica network and PANI chains. The surface area of calcined KGM‐1 is 40 m²/g (～15 times higher than KGM‐1), and the average pore size is 2.4 nm. The N₂ adsorption features also inform that PANI is present as a uniform layer within the pores of silica and because of that the silica pores are not completely blocked. The reversible redox transitions in PANI units and nanoporosity of KGM‐1 are effectively used for the electro‐driven loading/release of DNA or adenosine 5′‐triphosphate. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

Hydrogen bubbles and formation of nanoporous silicon during electrochemical etching

Many nanoporous Si structures, including those formed by common electrochemical etching procedures, produce a uniformly etched nanoporous surface. If the electrochemical etch rate is slowed down, details of the etch process can be explored and process parameters may be varied to test hypotheses and obtain controlled nanoporous and defect structures. For example, after electrochemical etching of heavily n‐doped (R = 0.05–0.5 Ω·cm) silicon 〈100〉 single crystals at a current density of 10 mA cm^?2 in buffer oxide etch (BOE) electrolyte solution, defect craters containing textured nanopores were observed to occur in ring‐shaped patterns. The defect craters apparently originate at the hydrogen/BOE bubble interface, which forms during hydrogen evolution in the reaction. The slower hydrogen evolution due to low current density and high BOE viscosity allows sufficient bubble residence time so that a high defect density appears at the bubble edges where local reaction rates are highest. Current‐carrying Si? OH species are most likely responsible for the widening of the craters. Reducing the defect/doping density in silicon lowers the defect concentration and thereby the density of nanopores. Measurements of photoluminescence lifetime and intensity show a distinct feature when the few nanopores formed at the ring edges are isolated from each other. Overall features observed in the photoluminescence intensity by XPS strongly emphasize the role of surface oxide that influences these properties. Copyright © 2005 John Wiley & Sons, Ltd.     

核壳硅碳复合微球固定相的制备及其在糖类分离中的应用

采用一步法在二氧化硅(SiO₂)表面涂覆酚醛树脂聚合物(PF),并在氮气气氛下碳化,制备了核壳硅碳复合微球(Sil@MC)固定相。实验对Sil@MC固定相进行形貌观察和孔结构分析,表明制备出的Sil@MC固定相具有良好的单分散性,包覆后的Sil@MC材料比表面积为302 m²/g,平均孔径为9.5 nm,孔容为0.63 cm³/g,说明通过共聚反应成功地将碳材料固定在二氧化硅上。将制备的Sil@MC材料作为HPLC固定相,采用匀浆法装柱,以乙腈-水(含0.1%(v/v)甲酸)作为流动相,发现Sil@MC色谱柱在高效液相色谱-质谱中可以实现4种极性糖类化合物(D-(+)-氨基葡萄糖盐酸盐、葡萄糖、D-(+)-海藻糖二水合物和棉子糖)的分离,然而未涂覆酚醛树脂的SiO₂材料未能对这4种极性糖类化合物实现分离。实验进一步对Sil@MC固定相的性能进行了评价,代表性的低聚糖异构体松三糖和棉子糖、耐斯糖和水苏糖及乳寡糖异构体3′-唾液酸乳糖和6′-唾液酸乳糖、乳-N-四糖和乳-N-新四糖在Sil@MC色谱柱中...     

Efficient production of nanoporous silicon carbide from rice husk at relatively low temperature

Nanoporous silicon carbide with a specific surface area of up to 186.45 m² g⁻¹ has been efficiently synthesized from waste rice husk using a magnesiothermic reduction at 950 °C as a key step. Throughout the entire process, the recovery rates of silicon, potassium and phosphorus from rice husk can reach 88.46, 91.5 and 65.5%, respectively. Turning rice husk waste into a real treasure, this promising method for producing porous SiC protects the environment and brings economic benefits.     

纳米孔碳负载Fe3O4催化剂上苯直接羟基化制苯酚

Fe3O4/CMK-3 was prepared by impregnation and used as a catalyst for the direct hydroxylation of benzene to phenol with hydro-gen peroxide. The iron species in the prepared catalyst was Fe3O4 because of the partial reduction of iron(III) to iron(II) on the surface of CMK-3. The high catalytic activity of the catalyst arises from the formation of Fe3O4 on the surface of CMK-3 and the high selectivity for phenol is attributed to the consumption of excess hydroxyl radicals by CMK-3. The effect of temperature,re...