Xi:Irritant;7758-02-3Relevant articles and documents
A novel zero valent metal bismuth for bromate removal: Direct and ultraviolet enhanced reduction
Huang, Hong,Liu, Guoshuai,Wang, Xiuheng
, p. 4148 - 4155 (2020/02/04)
Bromate (BrO3-) is a carcinogenic and genotoxic by-product of the ozone disinfection process. In this study, a new zero-valent metal, bismuth, was used to reduce bromate. Bismuth samples were prepared by a solvothermal method and characterized by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The morphology of the bismuth powder was microspheres assembled with dense nanosheets. The kinetics of the direct bromate reduction by bismuth accorded with the pseudo-first-order kinetics model. The rate coefficients of the initial bromate concentration of 1.00 mg L-1, 2.50 mg L-1, 5.00 mg L-1 were identically close to 0.08 min-1. For 0.20 mg L-1, a reaction rate coefficient near 0.10 min-1 was obtained. The reducing products of bromate included bromide ions (Br-) and bismuth oxybromides. The bromate removal efficiency was enhanced remarkably in the presence of ultraviolet (UV) light, and the corresponding kinetic coefficient was 4 times higher than that of direct reduction. The mechanism of ultraviolet enhancement was analyzed by diffuse reflectance spectroscopy (DRS), the density functional theory (DFT) calculation, open circuit potential (OCP) analysis, photocurrent measurement and linear sweep voltammetry (LSV). Besides, the influence of dissolved oxygen (DO) on bromate reduction efficiency and the sustainability of the as-prepared sample were investigated. DO inhibited the reduction rate obviously, but showed a slight effect on the formation of bromide ions. In the long-term periodic experiments, the kinetic coefficient decay occurred in both direct (without UV irradiation) and ultraviolet assisted bromate reduction. However, the kinetic coefficient of UV-assisted reduction (0.115 min-1) was about 2 times higher than that of the direct reduction in the last cycle of periodic experiments. In conclusion, the novel bromate reduction strategy based on the zero-valent bismuth metal material has been proved efficient and sustainable, which contributes to the development of drinking water treatment technologies.
Eu(O2C-C≡C-CO2): An EuII Containing Anhydrous Coordination Polymer with High Stability and Negative Thermal Expansion
Gramm, Verena K.,Smets, Daniel,Grzesiak, Ireneus,Block, Theresa,P?ttgen, Rainer,Suta, Markus,Wickleder, Claudia,Lorenz, Thomas,Ruschewitz, Uwe
, p. 2726 - 2734 (2020/02/20)
Anhydrous EuII–acetylenedicarboxylate (EuADC; ADC2? = ?O2C-C≡C-CO2 ?) was synthesized by reaction of EuBr2 with K2ADC or H2ADC in degassed water under oxygen-free conditions. EuADC crystallizes in the SrADC type structure (I41/amd, Z=4) forming a 3D coordination polymer with a diamond-like arrangement of Eu2+ nodes (msw topology including the connecting ADC2? linkers). Deep orange coloured EuADC is stable in air and starts decomposing upon heating in an argon atmosphere only at 440 °C. Measurements of the magnetic susceptibilities (μeff=7.76 μB) and 151Eu M?ssbauer spectra (δ=?13.25 mm s?1 at 78 K) confirm the existence of Eu2+ cations. Diffuse reflectance spectra indicate a direct optical band gap of Eg=2.64 eV (470 nm), which is in accordance with the orange colour of the material. Surprisingly, EuADC does not show any photoluminescence under irradiation with UV light of different wavelengths. Similar to SrADC, EuADC exhibits a negative thermal volume expansion below room temperature with a volume expansion coefficient αV=?9.4(12)×10?6 K?1.
Synthesis, characterization, and catalytic behavior of methoxy- and dimethoxy-substituted pyridinium-type ionic liquids
Manikandan, Chitrarasu,Ganesan, Kilivelu
, p. 3362 - 3367 (2014/12/11)
Synthesis of methoxy-substituted pyridinium-type ionic liquids from a nontoxic and easy method is described. Catalytic behaviors of synthesized ionic liquids were investigated with various concentrations for the Mannich reaction. We have observed that methoxy- and dimethoxy-substituted pyridinium bromides showed better catalytic behavior than other ionic liquids.
