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21.
Orcan Alpar 《Nonlinear dynamics》2015,82(1-2):435-449
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Laboratory batch sorption-desorption and column experiments were performed to better understand the effects of microbial exopolymeric substances (EPS) on Cr(III) sorption/desorption rates in the soil-water system. The experiments were carried out in two different modes: one mode (sorption) in which Cr(III) and EPS were applied simultaneously, and the other (desorption) included the sequential application of Cr(III) and EPS to the soil-water system. The batch sorption and desorption experiments showed that, while chromium(III) desorption was significantly enhanced in the presence of EPS relative to non-EPS-containing systems, the desorption rates were much smaller than the sorption rates, and the fraction dissolved by EPS accounted for only a small portion of the total chromium initially sorbed onto soil minerals. Similarly, the column experiments suggested that, while the microbial EPS led to an increase in Cr dissolution relative to non-EPS-containing systems, only a small portion of the total chromium initially added to the soil was mobilised. The differences observed in Cr sorption and desorption rates can be explained through the very low solubility and strong interactions of chromium species with soil minerals as well as the mass transfer effects associated with low diffusion rates. The overall results suggest that, while microbial EPS may play an important role in microbial Cr(VI) treatment in sub-surface systems due to the formation of soluble Cr-EPS complexes, the extent and degree of Cr mobilisation are highly dependent on the type of initial Cr sorption. 相似文献
24.
Yavuz Yardım Nurcan Alpar Zühre Şentürk 《International journal of environmental analytical chemistry》2013,93(13):1226-1241
ABSTRACTIn the present study, a simple, cheap and sensitive electrochemical method based on a cathodically pretreated boron-doped diamond (CPT-BDD) electrode is described for the detection of triclosan with the cationic surfactant (cetyltrimethylammonium bromide, CTAB) media. The oxidation of triclosan was irreversible and exhibited an adsorption controlled process. The sensitivity of the adsorptive stripping voltammetric measurements was significantly improved with addition of CTAB. Using square-wave stripping mode, a linear response was obtained for triclosan determination in Britton-Robinson buffer solution at pH 9.0 containing 2.5 × 10?4 M CTAB at around + 0.67 V (vs. Ag/AgCl) (after 30 s accumulation at open-circuit condition). The method could be used in the range of 0.01–1.0 μg mL?1 (3.5 × 10?8–3.5 × 10?6 M), with a detection limit of 0.0023 μg mL?1 (7.9 × 10?9 M). The feasibility of the proposed method for the determination of triclosan in water samples was checked in spiked tap water. 相似文献
25.
Ertuğrul Gazi Sağlam Ömer Çelik Hamza Yılmaz Nurcan Acar 《Phosphorus, sulfur, and silicon and the related elements》2013,188(11):1339-1346
Abstract Potassium and tetraphenylphosphonium salts of novel aryldithiofluorophosphonic acids were synthesized. Lawesson's Reagent was allowed to react with KF in acetonitrile to yield the potassium salt of p-methoxyphenyldithiofluorophosphonic acid. Treatment of the latter with tetraphenylphosphonium chloride resulted in the formation of the tetraphenylphosphonium salt. The structures of the compounds were elucidated by FTIR, 1H, 13C, 19F, and 31P NMR spectroscopy as well as by ESI-mass spectrometry. The molecular and crystal structure of the tetraphenylphosphonium salt, determined by single crystal X-ray diffraction, is also presented. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file. 相似文献
26.
In this study, benzenesulfonicacid‐1‐methylhydrazide (bsmh) derivatives such as 2‐hydroxy‐1‐naphtaldehydebenzenesulfonylhydrazone (Hnafbsmh) and its Ni(II), Pd(II), Pt(II), Cu(II), Co(II) complexes were synthesized. The structures of these complexes were investigated using elemental analyses (FT‐IR, LC‐MS, UV‐VIS), magnetic susceptibility and conductivity measurement techniques. The complexes were found to have general compositions [ML2]. All the synthesized complexes were evaluated in vitro as antimicrobial agents against representative strains of six gram‐positive and four gram‐negative bacteria and as an antifungal agent by disc diffusion methods. All the bacteria and fungi studied were screened against some commercial antibiotics to compare them with our chemical's zone diameters. 相似文献
27.
Nurcan KARACA 《Turkish Journal of Chemistry》2021,45(3):761
This article describes the synthesis of modified silica nanoparticles (SiO2-MPTMS) via the condensation reaction carried out between silanol moieties of silica nanoparticles and the trialkoxy silyl groups of (3-mercaptopropyl) trimethoxysilane (MPTMS). Then, SiO2-MPTMS nanoparticles in certain amounts (0.5 wt %, 1 wt %, 2.5 wt % and 5 wt %) were incorporated into thiol-ene resins consisting of bisphenol A glycerolate dimethacrylate and trimethylolpropane tris(3-mercaptopropionate) to prepare nanocomposite films via the photoinitiated thiol-ene polymerization in presence of 2,2-Dimethoxy-2-phenylacetophenone 99% as a photoinitiator. Fourier transform infrared spectroscopy, dynamic light scattering, scanning transmission electron microscopy, thermal gravimetric analyzer, and X-ray photoelectron spectrometer were employed to characterize SiO2-MPTMS nanoparticles. It was revealed that the nanosilica surface was successfully grafted by MPTMS with the grafting ratio of 22.9%. Properties of the nanocomposite films such as decomposition temperature, thermal glass transition temperature, tensile strength, hardness, and particle distribution were investigated and the results were compared with each other and neat film. The addition of MPTMS-modified silica particles did not improve the thermal stability of the films. In scanning electron microscopy study, it was seen that 2.5 wt % of these nanoparticles used as additives were about 200 nm in size and dispersed homogeneously in the polymer matrix. The increase in tensile strength of nanocomposite films compared to the neat film was measured as 77.3% maximum. 相似文献
28.
Elise Duhamel Alpar Pöllnitz Adina Stegarescu Prof. Dr. Anca Silvestru 《无机化学与普通化学杂志》2011,637(10):1355-1360
Redistribution reactions between diorganodiselenides of type [2‐(R2NCH2)C6H4]2Se2 [R = Et, iPr] and bis(diorganophosphinothioyl disulfanes of type [R′2P(S)S]2 (R = Ph, OiPr) resulted in the hypervalent [2‐(R2NCH2)C6H4]SeSP(S)R′2 [R = Et, R′ = Ph ( 1 ), OiPr ( 2 ); R = iPr, R′ = Ph ( 3 ), OiPr ( 4 )] species. All new compounds were characterized by solution multinuclear NMR spectroscopy (1H, 13C, 31P, 77Se) and the solid compounds 1 , 3 , and 4 also by FT‐IR spectroscopy. The crystal and molecular structures of 3 and 4 were determined by single‐crystal X‐ray diffraction. In both compounds the N(1) atom is intramolecularly coordinated to the selenium atom, resulting in T‐shaped coordination arrangements of type (C,N)SeS. The dithio organophosphorus ligands act monodentate in both complexes, which can be described as essentially monomeric species. Weak intermolecular S ··· H contacts could be considered in the crystal of 3 , thus resulting in polymeric zig‐zag chains of R and S isomers, respectively. 相似文献
29.
Levent Artok Melih Ku? Özge Aks?n-Artok Fatma Nurcan Dege Fatma Yelda Özk?l?nç 《Tetrahedron》2009,65(45):9125-902
Alkynes react with organoborons under a CO atmosphere in the presence of a rhodium(I) catalyst to afford mainly 5-aryl-2(5H)-furanones, α,β-unsaturated ketones, and indanones. The product selectivity can be tuned by modifying the reaction conditions. 相似文献
30.
Versatile Design Principles for Facile Access to Unstrained Conjugated Organoborane Macrocycles 下载免费PDF全文
Dr. Pangkuan Chen Dr. Xiaodong Yin Nurcan Baser‐Kirazli Prof. Dr. Frieder Jäkle 《Angewandte Chemie (International ed. in English)》2015,54(37):10768-10772
A facile and versatile approach was developed to access ambipolar boron‐containing macrocycles. Two examples of new conjugated cyclic motifs are presented with carbazole moieties as donors and borane moieties as acceptors embedded into the ring system. They were first predicted using computational methods. Possible targets with appropriately shaped π‐conjugated bridges that minimize the overall ring strain were identified and their geometry was optimized by DFT methods. The synthetic demonstration was then accomplished using organometallic condensation reactions under high dilution conditions. The resulting monodisperse macrocycles provide important insights into the design principles necessary for the preparation of new unstrained macrocycles with interesting optical and electronic characteristics. The current research also offers a more general approach to conjugated ambipolar B/N macrocycles as a promising new family of (opto)electronic materials. 相似文献