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The article describes how solar ultraviolet-A radiation can be used to digest samples as needed for voltammetric ultratrace determination of uranium(VI) in river water. We applied adsorptive stripping voltammetry (AdSV) using chloranilic acid as the complexing agent. Samples from the river Warnow in Rostock (Germany) were pretreated with either soft solar UV or wit artificial hard UV from a 30-W source emitting 254-nm light. Samples were irradiated for 12?h, and both methods yielded the same results. We were able to detect around 1?μg·L?1 of uranium(VI) in a sample of river water that also contained dissolved organic carbon at a higher mg·L?1 levels. No AdSV signal was obtained for U(VI) without any UV pre-treatment. Pseudo-polarographic experiments confirmed the dramatic effect of both digestion techniques the the AdSV response. The new method is recommended for use in mobile ultratrace voltammetry of heavy metals for most kinds of natural water samples including tap, spring, ground, sea, and river waters. The direct use of solar radiation for sample pre-treatment represents a sustainable technique for sample preparation that does not consume large quantities of chemicals or energy. Figure
Adsorptive stripping voltammetry response of uranium(VI) in a) Original Sample b) 6?h Solar UV Sample, c) 12?h Solar UV Sample, and d) 6?h UV Sample with standard additions of 2, 4 and 6?μg?L-1. Potentials are given vs. Ag/AgCl (3?M KCl). 相似文献
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Naz Mohammed Aghatabay Metin Tulu Yaghub Mahmiani Mehmet Somer Basaran Dulger 《Structural chemistry》2008,19(1):71-80
1,6-Bis(benzimidaz-2-yl)-3,4-dithiahexane ligand (L) and its mercury halide complexes were prepared and characterised. The
elemental analysis, molecular conductivity, FT-Raman, FT-IR (mid, far), 1H, 13C NMR and geometry optimization in MOPAC using MNDOd parameter on CACHE, prove the existence of neutral, mononuclear and the
distorted tetrahedral [Hg(L)X2] complexes. In all the three complexes, the ligand acts as a chelating bidentate, through two of the bridging sulphur atoms
and together with the monodentate coordination of the two anionic halide ligands to the metal centre forming a possible 4-coordinate
compounds. The antimicrobial activities of free ligand, its hydrochlorinated salt, mercury halides and the complexes are evaluated
using disk diffusion method in dimethyl sulfoxide (DMSO) as well as the minimal inhibitory concentration (MIC) dilution method,
against 10 bacteria. The obtained results from disk diffusion method are assessed in side-by-side comparison with those of
Penicillin-g, Ampicillin, Cefotaxime, Vancomycin, Oflaxacin and Tetracyclin well-known antibacterial agents. The results from
dilution procedure are compared with Gentamycin as antibacterial and Nystatin as antifungal. The antifungal activities are
reported on five yeast cultures namely Candida albicans, Kluyveromyces fragilis, Rhodotorula rubra, Debaryomyces hansenii and Hanseniaspora guilliermondii, and the results are referenced with Nystatin, Ketaconazole and Clotrimazole, commercial antifungal agents. In most cases,
the compounds show broad-spectrum (Gram+ & Gram− bacteria) activities that are comparatively, slightly less active or equipotent to the antibiotic and antifungal agents in
the comparison tests. 相似文献
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Roya Azad Abolfazl Bezaatpour Mandana Amiri Habibollah Eskandari Sima Nouhi Dereje H. Taffa Michael Wark Rabah Boukherroub Sabine Szunerits 《应用有机金属化学》2019,33(9)
A novel heterogeneous composite material based on reduced graphene oxide (rGO) and bismuth vanadate (BiVO4) was prepared and characterized by various techniques such as powder XRD, HRTEM, EADX, UV–Vis‐DRS, FT‐IR, Raman, BET and XPS analyses. The characterization results reveal that the rGO well decorated by BiVO4. The electrochemical impedance spectroscopy (EIS) shows the increasing of charge transfer of rGO/BiVO4 in presence of light irradiation. In this research, the pure BiVO4 and rGO/BiVO4 composite have been explored for photocatalytic reduction of nitroarenes. Among the prepared nanocomposites, rGO loaded with 10% BiVO4 catalyst (noted as rGO/BiVO4–10%) shows the best performance for the photo‐reduction of various nitroaromatic molecules to their corresponding amine compounds under visible‐light irradiation at room temperature. The catalyst exhibited in particular excellent photocatalytic activity for the conversion of 1,4‐dinitrobenzene to 4‐nitroanilline (100% conversion) in 20 min, 4‐chloronitrobenzene to 4‐chloroaniline and 2‐nitrophenol to 2‐aminophenol (100% conversion) in only 30 min. In addition, the conversion of 4‐bromonitrobenzene, 4‐iodonitrobenzene to their corresponding amine compounds (100% conversion) was achieved in 60 min. The catalyst was recovered for several times and reused without decreasing of its efficiency. 相似文献
4.
Muhammad Nazrul Islam Burak Aksu Mehmet Güncü Markus Gallei Metin Tulu Tarik Eren 《Journal of polymer science. Part A, Polymer chemistry》2020,58(6):872-884
Bacterial infection is a global problem, especially resistance acquired by bacteria against to antibiotics; there is urgent need for the development of antibiotics. Here, we proposed dendron-grafted polymers via ring opening metathesis polymerization (ROMP) featuring different with tailored hydrophobicity/hydrophilicity and cationic charges. Dendritic oxanorbornene derivatives were synthesized having two and six carbon linkers and their corresponding random and block copolymers were prepared having pendant pyridinium salt moieties via ROMP. In total, 12 different water-soluble dendronized cationic polymers featuring hexyl pyridinium moieties were prepared and investigated. Six carbon linker possessing triple charge density and hexyl pyridinium functionality each repeating unit copolymers exhibited high antibacterial activity against Gram-positive bacteria (S. aureus). However, all the polymers were inactive against Gram-negative bacteria (E. coli). Most of the copolymers are non-hemolytic (>HC 50 = 1,000 μg/ml). It was also observed that, there is no significant effect between block copolymers and random copolymers keeping hydrophobicity and cationic charge density constant. Zeta potential was measured to investigate the mechanism in solution via the interaction of polymers with S. aureus, while scanning electron microscope (SEM) measurements image confirms damage of the bacterial cell wall after implementation of biocidal polymer. 相似文献
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Naz Mohammed Aghatabay Metin Tulu Mehmet Somer Durata Haciu Ayberk Yilmaz 《Structural chemistry》2008,19(1):21-32
1,3-bis(benzimidazol-2-yl)-2-thiapropane (L) ligand and its zinc halide ZnX2 (X = Cl, Br, I) complexes have been synthesized. The compounds were characterized using the elemental analysis, molar conductivity,
FT-Raman, FT-IR (mid i.r., far i.r.), 1H and 13C NMR spectra, and quantum chemical calculations performed with Gaussian 03 package program set. The optimized geometries
and vibrational frequencies of the ligand and [Zn(L)Cl2] complex were calculated using the DFT/B3LYP method with a 6–31g(d) basis set. The geometry optimization of [Zn(L)Cl2] yields a slightly distorted tetrahedral environment around Zn ion, while the molecule clearly reveals the Cs symmetry. The
molar conductivity data reveals that the complexes are neutral. The ligand is bidentate, via two of the imine nitrogen atoms
in the bis-imidazole ring units, and together with the monodentate coordination of the two halides to the metal centre. 相似文献
6.
The problem of motion of the vortices around an oscillating cylinder in the presence of a uniform flow is considered. The Hamiltonian for vortex motion for the case with no uniform flow and stationary cylinder is constructed, reduced, and constant Hamiltonian (energy) curves are plotted when the system is shown to be integrable according to Liouville. By adding uniform flow to the system and by allowing the cylinder to vibrate, we model the natural vibration of the cylinder in the flow field, which has applications in ocean engineering involving tethers or pipelines in a flow field. We conclude that in the chaotic case forces on the cylinder may be considerably larger than those on the integrable case depending on the initial positions of vortices and that complex phenomena such as chaotic capture and escape occur when the initial positions lie in a certain region. 相似文献
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