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排序方式: 共有1229条查询结果,搜索用时 125 毫秒
1.
Isaiah R. Speight Dr. Igor Huskić Dr. Mihails Arhangelskis Dr. Hatem M. Titi Dr. Robin S. Stein Prof. Timothy P. Hanusa Prof. Tomislav Friščić 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(8):1811-1818
The “disappearing polymorph” phenomenon is well established in organic solids, and has had a profound effect in pharmaceutical materials science. The first example of this effect in metal-containing systems in general, and in coordination-network solids in particular, is here reported. Specifically, attempts to mechanochemically synthesize a known interpenetrated diamondoid (dia) mercury(II) imidazolate metal–organic framework (MOF) yielded a novel, more stable polymorph based on square-grid (sql) layers. Simultaneously, the dia-form was found to be highly elusive, observed only as a short-lived intermediate in monitoring solvent-free synthesis and not at all from solution. The destabilization of a dense dia-framework relative to a lower dimensionality one is in contrast to the behavior of other imidazolate MOFs, with periodic density functional theory (DFT) calculations showing that it arises from weak interactions, including structure-stabilizing agostic C−H⋅⋅⋅Hg contacts. While providing a new link between MOFs and crystal engineering of organic solids, these findings highlight a possible role for agostic interactions in directing topology and stability of MOF polymorphs. 相似文献
2.
Yingjie Zhang Ping Ning Xueqian Wang Langlang Wang Yixing Ma Qiang Ma Yibing Xie 《应用有机金属化学》2019,33(6)
Manganese‐ and cerium oxide‐modified titania catalysts were prepared by the deposition precipitation for the removal of elemental mercury (Hg0) from simulated yellow phosphorus off‐gas at low temperature. In addition, these catalysts were characterized by X‐ray diffraction, Brunauer–Emmett–Teller measurements, X‐ray photoelectron spectroscopy and field‐emission scanning electron microscope to determine the surface morphology of the obtained compounds and explore their formation mechanism. The results revealed that a Mn–Ce loading and reaction temperature of 10% and 150 °C, respectively, as well as a Mn/Ce molar ratio of 2:1, led to an optimal efficiency for the oxidation of elemental mercury. Furthermore, the effects of flue gas components were investigated. The presence of O2 clearly promoted the oxidation of Hg0. A CO atmosphere did not affect the Hg0 oxidation, when compared with N2, whereas the presence of H2S and water vapor inhibited the oxidation process. Furthermore, the X‐ray photoelectron spectroscopy spectra of Hg 4f revealed that the elemental mercury adsorbed by the catalyst is present as HgO. Finally, the Hg0 catalytic oxidation mechanism was discussed on the basis of the experimental results and characterization analysis. 相似文献
3.
4.
Umul Azizah 《Green Chemistry Letters and Reviews》2020,13(3):206-214
ABSTRACT A chemically modified-biosorbent was prepared by attaching dithizone onto Salacca zalacca skin waste for Hg2+ bioremoval. The material was synthesized by refluxing dithizone 5% with the Salacca zalacca skin powder followed by drying. The material was characterized through scanning electron microscopy, gas sorption analysis, and Boehm titration. The applicability of the material as biosorbent was tested for Hg2+ adsorption at room temperature. Findings suggested that the modification altered the surface properties of the biosorbent as indicated by the increased values for such surface parameters as specific surface area, pore volume, and quantitative functional groups. Particularly, the material demonstrated a high removal efficiency during Hg2+ adsorption, which fit the pseudo-second-order kinetics. The removal efficiency of Hg2+ was not influenced by the adsorbent dosage of 1–4?g/L. 相似文献
5.
《Arabian Journal of Chemistry》2022,15(1):103536
These days, an important concern in water contamination is the remaining dyes from various sources (for instance, dye and dye intermediates industries, pulp and paper industries, textile industries, craft bleaching industries, tannery, and pharmaceutical industries, etc.), and a broad range of persistent organic contamination has been entered to the wastewater treatment systems or natural water supplies. Indeed, it is extremely hazardous and toxic to the living organism. Therefore, it is necessary to remove these organic pollutants before releasing them into the environment. Photocatalysis is a quickly growing technology for sewage procedures. For this purpose, Cu2HgI4 nanostructures were prepared via facile, and cost-effective sonochemical method. The effect of varied circumstances, such as various surfactants, sonication power, and sonication time was considered on the crystallinity, structure, shape, and particle size of products. Cu2HgI4 possesses a suitable bandgap (2.2 eV) in the visible area. The photocatalytic performance of the Cu2HgI4 was surveyed for the elimination of various organic dyes under visible radiation and exposed that this compound could degrade and remove methyl orange about 94.2% in an acidic medium after 160 min under visible light. Besides, the result showed that various parameters, including, pH, dye concentration, types of dyes, catalyst dosages, and time of irradiation affected the photocatalytic efficiency. 相似文献
6.
A Terbium Metal–Organic Framework for Highly Selective and Sensitive Luminescence Sensing of Hg2+ Ions in Aqueous Solution 下载免费PDF全文
Dr. Tifeng Xia Dr. Tao Song Gege Zhang Prof. Dr. Yuanjing Cui Dr. Yu Yang Prof. Dr. Zhiyu Wang Prof. Dr. Guodong Qian 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(51):18429-18434
A series of isomorphic lanthanide metal–organic frameworks (MOFs) Ln(TATAB)?(DMF)4(H2O)(MeOH)0.5 (LnTATAB, Ln=Eu, Tb, Sm, Dy, Gd; H3TATAB=4,4′,4′′‐s‐triazine‐1,3,5‐triyltri‐p‐aminobenzoic acid) have been solvothermally synthesized and structurally characterized. Among these MOFs, TbTATAB exhibits good water stability and a high fluorescence quantum yield. Because mercury ions (Hg2+) have a high affinity to nitrogen atoms, and the space between multiple nitrogen atoms from triazine and imino groups is suitable for interacting with Hg2+ ions, TbTATAB shows highly selective and sensitive detection of Hg2+ in aqueous solution with a detection limit of 4.4 nm . Furthermore, it was successfully applied to detect Hg2+ ions in natural water samples. 相似文献
7.
This paper describes the method of assessing the composition of the intermetallic compounds in nanoscale electrolytic deposits. The formula was developed for calculating the deflection potential in the case of selective electrooxidation electronegative component of the alloy composition. The processes of electro binary electrolytic precipitation in mercury-rhodium chloride electrolyte by anodic stripping voltammetry were studied. It was established that an electrolytic precipitate contains rhodium, mercury and rhodium IC with mercury composition Hg5Rh. 相似文献
8.
金生 《中国无机分析化学》2015,5(4):20-23
利用DMA-80测汞仪直接测定固体样品中的汞,采用升温加热直接进行热分解、金汞齐反应,采用长、短双检测池,可直接测定固体、液体样品,汞含量在0.n~600.0ng/g范围内的样品都能准确地测定,每个样品测定时间约为5min。测定结果证明方法具有可靠性。 相似文献
9.
金生 《中国无机分析化学》2015,5(4)
本文的主要实验目的是利用DMA-80测汞仪直接测定固体样品中的汞并证明其方法可靠。采用升温加热直接进行热分解、金汞齐反应,采用长、短双检测池,可直接测定固体、液体样品,汞含量在0.n×10-9~600.0×10-9范围内的样品都能被很准确地测定,每个样品测定时间约为5min。 测试结果证明其方法具可靠性。 相似文献
10.
对人类健康和社会环境而言,汞离子被认为是毒性最大的金属离子之一.本文设计、合成了一种新型基于丹磺酰胺染料的荧光探针,并研究了其对金属阳离子的识别性质.研究结果表明:该荧光探针在水溶液中,对汞离子具有高度的选择性和良好的灵敏度,且不受其它金属阳离子的干扰.该探针对汞离子的检测限可以达到2.1×10-8 mol/L.该探针极低的检测限和良好的水溶性表明其可用于活细胞中检测汞离子.生物成像实验证实该探针具有良好的细胞膜透性和生物相容性. 相似文献