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181.
This article represents a step towards how to choose an ionic liquid as the solvent to improve metal ion (Ag+ and Pb2+) extraction. The liquid-liquid solvent extraction is proposed with the following imidazolium ionic liquids (ILs): 1-ethyl-3-ethylimidazolium,
or 1-butyl-3-ethylimidazolium, or 1-hexyl-3-ethylimidazolium bis{(trifluoromethyl)sylfonyl}imide [EEIM][NTf2], or [BEIM][NTf2], or [HEIM][NTf2], or 1-butyl-3-ethylimidazolium hexafluorophosphate [BEIM][PF6], or 1-hexyl-3-ethylimidazolium hexafluorophosphate [HEIM][PF6] and the popular 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM][PF6] for comparison. The effect of anion type (NTf2− versus PF6−) and the effect of structural components of an ionic liquid including alkyl chain length at the cation and the ethyl substituent
instead methyl at the cation, on the extraction and re-extraction processes by using dithizone as a metal chelator, were studied
at 296 K. Dithizone was employed to form neutral metal-dithizone complexes with heavy metal ions to extract them from aqueous
solution into the ILs.
Electronic Supplementary Material The online version of this article () contains supplementary material, which is available to authorized users.
Presented at the 236th ACS National Meeting, August 17–21, Philadelphia, USA. 相似文献
182.
Tamara R. Todorović Urszula Rychlewska Beata Warżajtis Dušanka D. Radanović Nenad R. Filipović Ivana A. Pajić Dušan M. Sladić Katarina K. Anđelković 《Polyhedron》2009
The bimetallic [Ni2(H2L2)2](ClO4)4 (1), [Ni2(HL2)(H2L2)](ClO4)3 (2) and [Zn2(H2L2)2](BF4)4 (3) complexes (H2L2 = N′,N′2-bis[(1E)-1-(2-pyridyl)ethylidene]propanedihydrazide) were synthesized and characterized. The structure of complexes (1) and (2) was established by X-ray analysis. NMR spectroscopy was used for the characterization of complex (3). The complexes (1) and (2) were obtained from the same synthetic reaction and two crystal types of these complexes have been isolated during the fractional crystallization process. 相似文献
183.
Kasthuri Balasubramani Packianathan Thomas Muthiah Urszula Rychlewska Agnieszka Plutecka 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(10):o586-o588
The title compound, 2,4‐diamino‐5‐(4‐chlorophenyl)‐6‐ethylpyrimidine‐1,3‐diium dinitrate, C12H15ClN42+·2NO3−, contains two crystallographically independent pyrimethamine (PMN) molecules, which differ in the relative orientations of the pyrimidine and benzene rings and of the ethyl substitutents. In both pyrimethamine molecules, all the pyrimidine N atoms are protonated, unlike most related compounds, in which only one pyrimidine N atom is protonated. The two pyrimethamine moieties are bridged by a variety of N—H⋯O(nitrate) interactions, including some three‐centre hydrogen bonds. 相似文献
184.
The surface tension of the pure hyperbranched polymer, Boltorn U3000, and binary mixtures of Boltorn U3000 with alcohols (1-butanol,
1-hexanol) have been measured at atmospheric pressure in the range of temperatures from 298.15 K to 328.15 K, or of Boltorn
U3000 with methyl-tert-butylether (MTBE) in the range of temperatures from 298.15 K to 318.15 K. These measurements have been provided to complete
information of the influence of temperature on surface tension for the selected polymer, which was chosen as a possible new
entrainer in extraction processes. The surface thermodynamic functions such as surface entropy and enthalpy have been derived
from the temperature dependence of the surface tension, as well as the critical temperature, parachor and speed of sound for
the pure polymer. The influences investigated here include the effects of the alkyl chain length of an alcohol and solvent
polarity on the surface tension. 相似文献
185.
Elbieta Wyrzykiewicz Andrzej Lpucha Urszula Sylwestrzak 《Magnetic resonance in chemistry : MRC》1984,22(4):272-273
The 13C NMR spectra of nine isomeric E-hydroxyazastilbenes (E-hydroxystyrylpyridines) have been fully assigned. The Ai and AiK empirical parameters of o-(m or p-)hydroxystyryl and 2-(3- or 4-)vinylpyridyl groups for the prediction, of chemical shifts of substituted styrylpyridines were calculated. 相似文献
186.
187.
In the anodic stripping voltammetric speciation of copper significant errors may be introduced as a result of sorption of Cu2+ onto active surfaces of the voltammetric cell assembly. A correction method was developed based on monitoring of the total copper concentration in solution using a -radiotracer; additionally this allowed us to study sorption phenomena in the voltammetric cell assembly.For copper speciation in a fresh water sorption-corrected complexing capacity data (total natural ligand concentration and conditional stability constant of formed complex) showed considerable discrepancies with uncorrected data. From the same sorption data it could be deducted that this was accountable to the presence of two active surface sites in the voltammetric cell assembly. 相似文献
188.
Aleksandra Pieczykolan Wioleta Pietrzak Urszula Gawlik-Dziki Renata Nowak 《Molecules (Basel, Switzerland)》2021,26(12)
Many plants that are commonly used in folk medicine have multidirectional biological properties confirmed by scientific research. One of them is Aerva lanata (L.) Juss. (F. Amaranthaceae). It is widely used, but there are very few scientific data about its chemical composition and pharmacological activity. The aim of the present study was to investigate the chemical composition of phenolic acid (PA)-rich fractions isolated from methanolic extracts of A. lanata (L.) Juss. herb using the liquid/liquid extraction method and their potential antioxidant, anti-inflammatory, and anti-diabetic properties. The free PA fraction (FA), the PA fraction (FB) released after acid hydrolysis, and the PA fraction (FC) obtained after alkaline hydrolysis were analysed using liquid chromatography/electrospray ionization triple quadrupole mass spectrometry (LC-ESI-MS/MS). The phenolic profile of each sample showed a high concentration of PAs and their presence in A. lanata (L.) Juss. herb mainly in bound states. Thirteen compounds were detected and quantified in all samples, including some PAs that had not been previously detected in this plant species. Bioactivity assays of all fractions revealed high 2,2-diphenyl-1-picrylhydrazyl (DPPH•) (2.85 mM Trolox equivalents (TE)/g) and 2,2-azino-bis-3(ethylbenzthiazoline-6-sulphonic acid) (ABTS•+) (2.88 mM TE/g) scavenging activity. Fraction FB definitely exhibited not only the highest antiradical activity but also the strongest xanthine oxidase (XO) (EC50 = 1.77 mg/mL) and lipoxygenase (LOX)(EC50 = 1.88 mg/mL) inhibitory potential. The fraction had the best anti-diabetic properties, i.e., mild inhibition of α-amylase (EC50 = 7.46 mg/mL) and strong inhibition of α-glucosidase (EC50 = 0.30 mg/mL). The activities of all analysed samples were strongly related to the presence of PA compounds and the total PA content. 相似文献
189.
Urszula Wjcik-Bojek Joanna Rywaniak Przemysaw Bernat Anna Podsdek Dominika Kajszczak Beata Sadowska 《Molecules (Basel, Switzerland)》2021,26(6)
Staphylococcus aureus is still one of the leading causes of both hospital- and community-acquired infections. Due to the very high percentage of drug-resistant strains, the participation of drug-tolerant biofilms in pathological changes, and thus the limited number of effective antibiotics, there is an urgent need to search for alternative methods of prevention or treatment for S. aureus infections. In the present study, biochemically characterized (HPLC/UPLC–QTOF–MS) acetonic, ethanolic, and water extracts from fruits and bark of Viburnum opulus L. were tested in vitro as diet additives that potentially prevent staphylococcal infections. The impacts of V. opulus extracts on sortase A (SrtA) activity (Fluorimetric Assay), staphylococcal protein A (SpA) expression (FITC-labelled specific antibodies), the lipid composition of bacterial cell membranes (LC-MS/MS, GC/MS), and biofilm formation (LIVE/DEAD BacLight) were assessed. The cytotoxicity of V. opulus extracts to the human fibroblast line HFF-1 was also tested (MTT reduction). V. opulus extracts strongly inhibited SrtA activity and SpA expression, caused modifications of S. aureus cell membrane, limited biofilm formation by staphylococci, and were non-cytotoxic. Therefore, they have pro-health potential. Nevertheless, their usefulness as diet supplements that are beneficial for the prevention of staphylococcal infections should be confirmed in animal models in the future. 相似文献
190.
In this paper we investigate the spectral exponent, i.e. logarithm of the spectral radius of operators having the form
and acting in spaces Lp(X, μ), where X is a compact topological space, φk∈C(X), φ = (φk)k=1N∈C(X)N, and
are linear positive operators (Ukf≥ 0 for f≥ 0). We consider the spectral exponent ln r(Aφ) as a functional depending on vector-function φ. We prove that ln r(Aφ) is continuous and on a certain subspace
of C(X)N is also convex. This yields that the spectral exponent is the Fenchel-Legendre transform of a convex functional
defined on a set
of continuous linear positive and normalized functionals on the subspace
of coefficients φ that is
相似文献