A novel polymeric sorbent for selective extraction of U(VI) and Th(IV) from highly acidic wastes was prepared by modifying Merrifield chloromethylated resin with N,N,N′,N′-tetrahexylmalonamide. The functionalized resin was characterized by FT-IR spectroscopy, CPMAS NMR spectroscopy, CHN elemental analysis and thermo-gravimetric analysis. Various physiochemical parameters responsible for quantitative extraction of metal ions were studied by static and dynamic methods. The resin exhibited very good extractability over a wide range of acidity (0.01–10 M) with a faster exchange rate (saturation possible within 20 min) and high sorption capacities (0.645 and 0.558 mmol g−1) for U(VI) and Th(IV), respectively. Quantitative metal desorption was achieved by using 0.5 M (NH4)2CO3 for both analytes. The significant feature of the resin is the possibility of sequential separation and the ability to elute only U(VI) with water, thus offering the possibility of sequential separation of U(VI) and Th(IV). Interference studies with commonly encountered metal ions, rare earth ions and electrolytes were conducted. Enrichment factors of 400 and 350 with a limit of quantification of 20 ng mL−1 and 50 ng mL−1 were achieved for the two analytes. All the analytical data were within 3.8% RSD, reflecting the reproducibility and reliability of the method. 相似文献
The latex of Euphorbia nivulia afforded three new ingol diterpenes, 3-acetyl-8-methoxyl-7-angolyl-12-hydroxylingol (7), 3,12-diacetyl-7-hydroxy-8-methoxylingol (8), and 3,12-diacetyl-7-angolyl-8-hydroxylingol (9) along with five known ingol diterpenes 2-6 and a known triterpene cyclonivulinol (1). Their structures were established by means of spectroscopic analysis. Diterpenes 2-9 were evaluated for their cytotoxic activity. 相似文献
Chemical examination of the aerial parts of Cleistanthus collinus afforded the arylanphthalide lignans, cleistanone (1), diphyllin (2), cleistanthins A (3), C (4) and D (5), and 4-O-(3"-O-methyl-beta-D-glucopyranosyl)-diphyllin (6). The first compound is a new member of the rare group of arylnaphthalide lignans containing an alkoxy group on the lactone ring. The structure of the compound was determined from its spectral data, chemical transformations and partial synthesis from diphyllin (2). The new lignan, 1 and its acetyl derivative, 7 were found to exhibit cytotoxicity against MT(2) cell lines. 相似文献
Pelecypod shell originated from Kolleru lake of Andhra Pradesh is used in the present work. It contains Mn(II) and Fe(III) in traces. The EPR spectrum of the compound is due to Mn(II) which is in three independent sites. The three g values are evaluated with slight differences. The hyperfine component varies from 9.33 to 9.49mT. The zero field splitting parameter is also ranges from 43.8(1) to 44.1(1)mT. Using the covalence parameter the number of ligands around metal is estimated as 20. In EPR spectrum Fe(III) is identified. The optical absorption spectrum is attributed to Mn(II) in octahedral geometry. Further 10 Dq band is attributed to Fe(II) in the optical absorption spectrum. NIR spectral results are due to water fundamentals, whereas IR and Raman spectrum is due to carbonate ion fundamentals. 相似文献
Colloid Journal - The effect of various surfactants on aggregation of fullerene C60 is discussed. Formation of ordered structures via C60-surfactant interactions at a specific [C60]/[Triton X-100]... 相似文献
We report the complete (1)H and (13)C NMR assignment of impurities of six Lopinavir (2S)-N-[(2S, 4S, 5S)-5-{[2-(2,6-dimethylphenoxy)acetyl]amino}-4-hydroxy-1,6-diphenyl hexan-2-yl]-3-methyl-2-(2-oxo-1,3-diazinan-1-yl)butan- amide. Two of the impurities are regioisomers and GCOSY used to differentiate the two structures. The spectral assignments for all six impurities were achieved by concerted application of one and two-dimensional NMR techniques ((1)H NMR, (13)C NMR, DEPT, GCOSY, GHSQC and GHMBC). 相似文献
Heteroleptic molybdenum complexes bearing 1,5-diaza-3,7-diphosphacyclooctane (P2N2) and non-innocent dithiolene ligands were synthesized and electrochemically characterized. The reduction potentials of the complexes were found to be fine-tuned by a synergistic effect identified by DFT calculations as ligand-ligand cooperativity via non-covalent interactions. This finding is supported by electrochemical studies combined with UV/Vis spectroscopy and temperature-dependent NMR spectroscopy. The observed behavior is reminiscent of enzymatic redox modulation using second ligand sphere effects. 相似文献
The authors report on the preparation of a hollow-structured cobalt ferrite (CoFe2O4) nanocomposite for use in a non-enzymatic sensor for hydrogen peroxide (H2O2). Silica (SiO2) nanoparticles were exploited as template for the deposition of Fe3O4/CoFe2O4 nanosheets, which was followed by the removal of SiO2 template under mild conditions. This leads to the formation of hollow-structured Fe3O4/CoFe2O4 interconnected nanosheets with cubic spinel structure of high crystallinity. The material was placed on a glassy carbon electrode where it acts as a viable sensor for non-enzymatic determination of H2O2. Operated at a potential of ?0.45 V vs. Ag/AgCl in 0.1 M NaOH solution, the modified GCE has a sensitivity of 17 nA μM?1 cm?2, a linear response in the range of 10 to 1200 μM H2O2 concentration range, and a 2.5 μM detection limit. The sensor is reproducible and stable and was applied to the analysis of spiked urine samples, where it provided excellent recoveries.
Graphical abstract Schematic of a cobalt ferrite (CoFe2O4) hollow structure for use in electrochemical determination of H2O2. The sensor shows a low detection limit, a wide linear range, and excellent selectivity for H2O2.
This paper presents an adjoint method for the optimum shape design of unsteady flows. The goal is to develop a set of discrete unsteady adjoint equations and the corresponding boundary condition for the non-linear frequency domain method. First, this paper presents the complete formulation of the time dependent optimal design problem. Second, we present the non-linear frequency domain adjoint equations for three-dimensional flows. Third, we present results that demonstrate the application of the theory to a three-dimensional wing. 相似文献