Methods for Elemental Analysis of Size-Resolved PM Samples Collected on Aluminium Foils: Results of an Intercomparison Exercise

Aluminium is the most common substrate in studies using impactors for the measurement of the number or the weight of size-segregated atmospheric particulate matter (PM), as its characteristics perfectly fit impactor requirements. However, its use is not recommended by manufacturers when one of the purposes of the study is the determination of the metal content in the sample. The aim of this work was to develop an efficient analytical procedure for the removal and acid digestion of PM samples collected on aluminium foils by a cascade impactor to perform the determination of metals. The possibility of performing the trace metal analysis of PM samples collected using aluminium foils is of great importance, as it allows the determination of an accurate size distribution and the elemental composition of the PM collected on each impactor stage. Two procedures were optimised by using different digestion and analysis techniques. Both procedures were then applied to the two halves of several Dekati low-pressure impactor (DLPI) samples, and the results were critically compared. The two procedures proved to be effective in the determination of extremely low concentrations of a large suite of analytes in different size fractions of PM emitted by a brake system.     

ICP-MS/ICP-AES法快速测定转基因棉花种子中的矿质元素和重金属含量

转基因植物生理生态已成为当前的研究热点,外源基因的导入可能会造成许多无法预料的结果。文章借助ICP-MS/ICP-AES技术对我国自己研制的转基因棉花和对照种子中的矿质元素和重金属进行了研究。结果显示,转基因棉花种子中,所测量的15种矿质元素含量有12种显著低于非转基因对照,说明转基因棉花种子吸收和累积矿质元素的能力下降;而只有镁、铁、铜含量高于对照。在测定的九种重金属(有害元素)中有七种转基因抗虫棉高于对照,特别是铝和砷的含量高出许多甚至上百倍,而铬和汞两种重金属含量明显低于对照。     

实时磁性测试深入理解锂离子电池中的过渡金属催化作用

催化剂由于具有降低电化学过电位和改善动力学条件的能力,在各种储能器件中起着至关重要的作用.在锂离子电池中,首圈放电过程中形成的固体电解质界面膜,通常被认为是一旦形成就稳定不分解的.而在过渡金属的催化下,这种电解质分解衍生的聚合物凝胶状膜(PGF)能可逆地形成和分解.这种过渡金属催化机制可以进行催化储锂,即形成的PGF具...     

以太网芯片重离子单粒子效应试验

为评估和研究工业以太网芯片KSZ8851-16MLLJ在空间环境中的适应性,利用重离子源对芯片进行了单粒子试验。根据以太网芯片的结构和功能制订了单粒子实验方案,得出了实验数据,并对实验数据进行了整理和研究。实验和研究表明：工业以太网芯片KSZ8851-16MLLJ具有一定的抗单粒子辐射能力;在不同网络传输条件下,发生单粒子翻转的机率也不相同;在持续的单粒子辐射下,以太网芯片会发生电流阶跃,第二次电流阶跃时产生单粒子锁定,在工程应用中可以利用电流阶跃监测芯片的辐射水平。     

GO-SWCNT Buckypapers as an Enhanced Technology for Water Decontamination from Lead

Water decontamination is an important challenge resulting from the incorrect disposal of heavy metal waste into the environment. Among the different available techniques (e.g., filtration, coagulation, precipitation, and ion-exchange), adsorption is considered the cheapest and most effective procedure for the removal of water pollutants. In the last years, several materials have been tested for the removal of heavy metals from water, including metal-organic frameworks (MOFs), single-walled carbon nanotubes (SWCNTs), and graphene oxide (GO). Nevertheless, their powder consistency, which makes the recovery and reuse after adsorption difficult, is the main drawback for these materials. More recently, SWCNT buckypapers (SWCNT BPs) have been proposed as self-standing porous membranes for filtration and adsorption processes. In this paper, the adsorption capacity and selectivity of Pb²⁺ (both from neat solutions and in the presence of other interferents) by SWCNT BPs were evaluated as a function of the increasing amount of GO used in their preparation (GO-SWCNT buckypapers). The highest adsorption capacity, 479 ± 25 mg g⁻¹, achieved for GO-SWCNT buckypapers with 75 wt.% of graphene oxide confirmed the effective application of such materials for cheap and fast water decontamination from lead.     

芳香族化合物的脱芳构化反应

芳香族化合物稳定、易得,通过芳香族化合物的脱芳构化反应,制备官能化的脂肪六元碳环化合物,早以引起人们的广泛兴趣。本文对六类脱芳构化反应进行了逐一评述,其包括：氧化脱芳构化反应;还原脱芳构化反应;光催化脱芳构化反应;亲核加成脱芳构化反应;σ-键迁移重排脱芳构化反应;过渡金属参与的脱芳构化反应。其中,过渡金属参与的脱芳构化反应,反应条件温和,反应底物广泛,可应用于生物活性物质的合成。     

大孔球形纤维素吸附剂的制备及性能研究

本课题以天然棉纤维为原料,通过碱化、老化、碳化以及溶解,制得纤维素粘胶,按一定比例加入Ca-CO3,然后,采用反相悬浮再生法,制备纤维素球,在HCl-NaCl-CaCl2。混合溶液中除去CaCO3后,得大孔球形纤维素经SEM对整体结构和表面结构进行了表征。这种大孔球经环氧化后,制备了一种开链氮杂冠醚化大孔球形纤维素吸附剂（PSC-OCAC）,测定了PSC-OCAC对几种常见金属离子的吸附性能,并应用到江河水体中几种金属的分离、富集,建立起PSC-OCAC-分离富集-火焰原子吸收分光光度法,测定水体中痕量重金属总量的方法,测定了南充境内两河、嘉陵江水体中的几种常见重金属含量。     

Chemical Composition and Potential Practical Application of 15 Red Algal Species from the White Sea Coast (the Arctic Ocean)

Though numerous valuable compounds from red algae already experience high demand in medicine, nutrition, and different branches of industry, these organisms are still recognized as an underexploited resource. This study provides a comprehensive characterization of the chemical composition of 15 Arctic red algal species from the perspective of their practical relevance in medicine and the food industry. We show that several virtually unstudied species may be regarded as promising sources of different valuable metabolites and minerals. Thus, several filamentous ceramialean algae (Ceramium virgatum, Polysiphonia stricta, Savoiea arctica) had total protein content of 20–32% of dry weight, which is comparable to or higher than that of already commercially exploited species (Palmaria palmata, Porphyra sp.). Moreover, ceramialean algae contained high amounts of pigments, macronutrients, and ascorbic acid. Euthora cristata (Gigartinales) accumulated free essential amino acids, taurine, pantothenic acid, and floridoside. Thalli of P. palmata and C. virgatum contained the highest amounts of the nonproteinogenic amino acid β-alanine (9.1 and 3.2 μM g⁻¹ DW, respectively). Several red algae tend to accumulate heavy metals; although this may limit their application in the food industry, it makes them promising candidates for phytoremediation or the use as bioindicators.     

Simultaneous Removal of Antibiotics and Heavy Metals with Poly(Aspartic Acid)-Based Fenton Micromotors

The discharge of diverse pollutants has led to a complex water environment and posed a huge health threat to humans and animals. Self-propelled micromotors have recently attracted considerable attention for efficient water remediation due to their strong localized mass transfer effect. However, a single functionalized component is difficult to tackle with multiple contaminants and requires to combine different decontamination effects together. Here, we introduced a multifunctional micromotor to implement the adsorption and degradation roles simultaneously by integrating the poly(aspartic acid) (PASP) adsorbent with a MnO₂-based catalyst. The as-prepared micromotors are well propelled in contaminated waters by MnO₂ catalyzing hydrogen peroxide. In addition, the catalytic ramsdellite MnO₂(R-MnO₂) inner layer is decorated with Fe₂O₃ nanoparticles to improve their catalytic performance, contributing to an excellent degradation ability with 90% tetracycline (TC) removal in 50 minutes by enhanced Fenton-like reactions. Combining the attractive adsorption capability of poly (aspartic acid) (PASP), the composite micromotors offer an efficient removal of heavy metal ions in short time. Moreover, the designed micromotors are able to simultaneously remove antibiotic and heavy metals in mixed contaminants circumstance just in single treatment. This multifunctional micromotor with distinctive decontamination ability exhibits a promising prospective in treating multiple pollutants in the future.     

Accessing C2-Functionalized 1,3-(Benz)azoles through Transition Metal-Catalyzed C−H Activation

The skeletal presence of 1,3-azoles in a variety of bioactive natural products, pharmacophores, and organic materials demands the derivatization of such heteroarenes regioselectively. Plenty of cross-coupling as well as cyclocondensation reactions have been performed to build up these skeletons but remained commercially unrealizable. A couple of severe drawbacks are faced by these traditional protocols that require a more straightforward strategy to obviate them. Transition metal-catalyzed C−H functionalization has emerged as a superior alternative in that context. 1,3-Azoles and their benzo counterparts have been extensively functionalized exploiting both noble and earth-abundant transition metals. Lately, C-2 functionalization have gained much traction due to the ease of attaining high regioselectivity and installation of synthetically manipulative functionalities. This critical review presents a bird‘s eye view of all major C-2 functionalization of (benz)azoles catalyzed by a diverse set of metals performed over the past 15 years.