445 resultados para Cu2
Resumo:
Cu2+,pHCu2+Cu2+,;pH6Cu2+20 mg/L0.25 mm,,,Na+Ca2+Cu2+,0.1mol/L HCl96.1%Cu2+Thomas,10.94mg/gCu2+,
Resumo:
Cu2+.LangmuirFreundlich,,(Go)(Ho)(So).,Langmuir,RL01,;,Cu2+;HoSo12.206kJmol-121.534Jmol-1K-1,Go,Cu2+,,.LangmuirCu2+.
Resumo:
,,pH 2.0,4,30 g/L,1 h,4,Cd 98.9%Pb 99.6%Zn 98.9%Cu 98.7%;,4Cd 3.2Pb 90.8Zn 27.3Cu 52.4 mg/g;,60 minElovich,4,4Pb2+>Cd2+>Cu2+>Zn2+
Resumo:
Nanosized Ce1-xCuxOy materials were prepared by complexation-combustion method. The structural characteristics and redox behaviors were investigated using X-ray diffraction (XRD), temperature programmed reduction (H-2-TPR), UV-Vis, and Raman spectroscopies. In XRD patterns, no evidence of CuO diffraction peaks are observed for the Ce1-xCuxOy samples calcinated at 650 degreesC for 5 h, until the Cu/(Ce + Cu) ratio is higher than 0.4. The stepwise decrease of the 2theta value of CeO2 in Ce1-xCuxOy with the increasing of Cu concentration suggests that the CU2+ ions incorporate into the CeO2 lattice to form Ce1-xCuxOy solid solutions for low Cu/(Ce + Cu) ratios (x less than or equal to 0.1). The CuO phase begins to segregate from the solid solutions with the further increasing of Cu/(Ce+Cu) ratio. The Raman mode at 1176 cm(-1) ascribed to the enhanced defects appears for CeO2 and the Ce0.9Cu0.1Oy solid solution. Compared with CeO2 alone, the Raman mode of cubic CeO2 shifts from 462 to 443 cm(-1) for the Ce0.9Cu0.1Oy solid solution. The H-2 consumption of the fresh Ce0.95Cu0.05Oy is 1.65 times higher than that needed to reduce CuO to Cu, and it increases to 2.4 after a reoxidation of the partially reduced Ce0.95Cu0.05Oy at 300 degreesC, which indicates that the CeO2 phase is also extensively reduced. Compared with the high Cu/(Ce+Cu) ratio sample Ce0.7Cu0.3Oy, the Ce0.9Cu0.1Oy solid solution shows high and stable redox property even after different reoxidation temperatures. When the reoxidation temperature exceeds 200 degreesC, the a peak (similar to170 degreesC) ascribed to the reduction of surface oxygen disappears, and the P peak (similar to190 degreesC) ascribed to the reduction of Cu2+ species and the partial reduction of bulk CeO2 shifts to higher temperatures with the H-2 consumption 1.16 times higher than that for fresh sample. The result demonstrates that the redox property of the CeO2 is Significantly improved by forming the Ce1-xCuxOy solid solutions.
Resumo:
A method has been established to study the competing binding of metal ions with protein by a combined technique of microdialysis with high performance liquid chromatography (HPLC). Ni2+, Cd2+, Zn2+, Cu2+ and human serum albumin (HSA) were chosen as model metal ions and protein. The experimental results show that Ni2+ and Cu2+ share a common primary binding site on HSA, and Zn2+ and Cd2+ share a different common primary binding site from them, but there is a common multi-metal binding site for all of those four metal ions. This method show advantages of fast sampling, easily to be operated and especially to be useful when ideal spectroscopic probes are not available for the study of interaction between protein and metal ions.
Resumo:
A new class of ionophores with troponoid and thiocrown ether units was prepared. Cation-binding properties of troponoid dithiocrown ethers were characterized using UV and NMR spectroscopies. They have affinity with metal ions; in particular, they showed high affinity with Hg2+. Transport of Hg2+ through a CHCl3 liquid membrane with troponoid dithiocrown ethers was examined in a U-type cell. From an aqueous solution of HgCl2 and CuCl2, Hg2+ is transferred selectively and smoothly, while the Cu2+ remained quantitatively in the original solution. The cavity size of dithiocrown ethers is one of the requirements for effective extraction and transport of Hg2+. However, derivatives with a smaller cavity still extract and transport Hg2+. A polymer-supported troponoid dithiocrown ether was prepared to transport Hg2+ effectively and repeatedly. Comparing the troponoid dithiocrown ether with the benzenoid dithiocrown ether with a similar cavity size, the former was more effective for the transport of Hg2+. It is proposed that the tropone ring assisted the release of Hg2+ from the complex by Coulomb repulsion between the protonated tropone ring and Hg2+.
Resumo:
This article reports on the performance of a bismuth-coated carbon microdisk electrode (BiFE) for the determination of trace heavy metals by anodic stripping voltammetry (ASV). The BiFE was prepared by electrodeposition of a metallic bismuth film onto the microdisk, by applying an in-situ electroplating procedure. To test the performance of the BiFE, ASV measurements were performed on synthetic solutions containing Cd2+, Pb2+, and Cu2+ as target ions. The results indicated that cadmium and lead gave well-defined ASV peaks with no interference, and their quantitative determination could be carried out straightforwardly. In particular, linear calibration curves over the range 5.0 x 10-8-1.0 x 10-6M for both ions, and detection limits of 7.8 and 2.9 nM, for cadmium and lead, respectively, after applying a 60 sec preconcentration step, were obtained. The reproducibility was also satisfactory, the relative standard deviation (RSD) being within 2.5% for both ions. Copper, instead, gave an ASV response that. in most experimental conditions, overlapped with that of bismuth. This circumstance made the determination of copper at the BiFE difficult. Since the latter element could be detected reliably at the uncoated carbon microdisk electrode (CE), both BiFE and CE were employed, respectively, for the determination of lead and copper ions in drinking water, wine, and tomato sauce.
Resumo:
Synthetic procedures for new mixed-donor macrocycle compounds were reported. The macrocyclic compounds were used in solvent extraction metal picrates such as Ag+, Hg2+, Cd2+, Zn2+, Cu2+, Ni2+, Mn2+, Pb2+, and Co2+. The metal picrate extractions were investigated at 250.1C with the aid of UV-visible spectrometry. It was found that 6,7,9,10,12,13,23,24-octahydro-19H,26Hdibenzo[h,t](1,4,7,13,16,22,10,19) dioxatetrathiadiazasiclotetracosine-20,27(21H,28H)-dione showed selectivity towards Ag+, Hg2+, and Cd2+ among the other metals. The extraction constants (Log Kex) and complex compositions were determined for the Ag+ and Hg2+ complexes for this compound and 9,10,12,13,23,24,26,27,29,30-decahydro-5H,15H-dibenzo-[h,w][1,4,7,13,16,19,25-,10,22] dioxapentathiadiazacycloheptacosine-6,16(7H,17H)-dione.
Resumo:
Cu2+Zn2+,-Cu2+Zn2+Cu2+Zn2+,,Cu2+,;pH,,Cu2+Cu2+Zn2+,
Resumo:
3 200~3 600 m185,1B1394,873 U/mL16S rDNA,(Bacillus subtilis):60,pH 8.0,3040,40~60,;Mn2+Mg2+Ca2+,Hg2+Fe3+Cu2+Zn2+Fe2+;PMSF,
Resumo:
Cu2+.,Cu2+.LC50:30.2116.26μg/L();449.521130.34μg/L(Cu2+).Cu2+Cu2+,Cu2+>500μg/L,;.Cu2+,,.,Cu2+,Cu2+.,Cu2+500μg/L,Cu2+Cu2+,Cu2+.
Resumo:
NH4ACEDTA,Cu2+(<10m,1050m,50250m),Cu2+,Cu2+,<10m,,:,Cu2+,,Cu2+,
Resumo:
In this work, we report the first application of water-soluble fluorescent Ag nanoclusters in fluorescent sensors. The fluorescence of poly(methacrylic acid) (PMAA)-templated Ag nanoclusters was found to be quenched effectively by Cu2+, but not when other common metal ions were present. By virtue of the specific response toward the analyte, a new, simple, and sensitive fluorescent method for detecting Cu2+ has been developed based on Ag nanoclusters.
Resumo:
The electronic, magnetic, and mechanical properties of CaCu3V4O12 are investigated by use of the density functional theory method. The calculated results indicate that CaCu3V4O12 is a half-metallic and ferrimagnetic compound. The magnetic coupling for Cu-V is antiferromagnetic, while those for Cu-Cu and V-V are ferromagnetic. The obtained elastic constants suggest that the compound is mechanically stable. The calculated oxidation states and density of states reveal the existence of a mixed valence for Cu and V. This supports the experimental observation of the mixed valence in Ca2+Cu2+Cu2+(V25+V24+)O-12.
