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51.
In this study, a new Schiff base (H4TSTE) was synthesized and characterized by elemental analysis, FT-IR, NMR and MS spectral data. Liquid–liquid extraction process was performed for removal of Cu(II), Mn(II), Ni(II), Pb(II) and Zn(II) from aqueous solutions by means of H4TSTE. The extractions were investigated depending on the concentration of picric acid, metal ion and H4TSTE ligand. Response surface methodology (RSM) was first applied to optimize metal ion-binding properties of H4TSTE. The extraction efficiency was estimated to be >98% for all metals by models. Under the same conditions, the extraction efficiency was experimentally found to be >97% with a relative standard deviation within ±0.10 (N = 4), indicating the suitability of the models. 相似文献
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53.
In the current study, a new cloud point extraction (CPE) procedure was developed for the separation and preconcentration of inorganic soluble As species, As(III), As(V), and total As in water and beverage samples. Selective ion-pairing complex of As(III) with Neutral red (NRH+) being a cationic phenazine-based dye in presence of citric acid at pH 2.0 was extracted into the surfactant-rich phase of octylphenoxypolyethoxyethanol (Triton X-114) from samples. After phase separation, the preconcentrated As(III) was determined by means of spectrophotometer at 542 nm. After optimization of the CPE conditions, a preconcentration factor of 50 and the detection and quantification limits of 1.44 and 4.8 μg L?1 with a correlation coefficient of 0.9953 were obtained from the calibration curve constructed in the range of 5–1500 μg L?1 for As(III). The precision of the method (as RSD) was in the range of 2.2–4.5 % (25, 100, and 750 μg L?1, N?=?5). The As(V) contents of samples were calculated from the difference between As(III) and total As contents after the reduction of As(V) to As(III) with mixture of KI and ascorbic acid at HCl media. The method is very versatile and inexpensive because it exclusively used conventional UV–Vis spectrophotometry. The method was succesfully applied to the simultenous determination of inorganic arsenic species in different water and beverage samples. Its accuracy and precision were controlled by analysis of two certified reference materials (CRMs). 相似文献
54.
Determination of hydroquinone using poly(3‐methylthiophene) synthesized electrochemically on pt electrode in methylene chloride 下载免费PDF全文
Poly(3‐methylthiophene) (P3MT) film was synthesized by potentiodynamic method on Pt electrode in methylene chloride solution containing 0.10M tetrabuthlammonium perchlorate supporting electrolyte and used for the determination of hydroquinone (HQ) with amperometric I–t method in solution consisting of NaHSO4/Na2SO4 (SBS; pH 2.0). This modified electrode has a lower working potential and good operational stability due to reducing electrode fouling when compared with the direct oxidation of HQ at the bare Pt electrode. Limit of detection, limit of quantification, and the linear response range were found to be 1.32 × 10?5 mM, 4.41 × 10?5 mM, and between 4.41 × 10?5 – 50.0 mM (R2 = 0.997), at 0.50 V versus saturated calomel electrode, respectively. HQ determination in complex matrix was checked using real samples to demonstrate the applicability of modified electrode. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40859. 相似文献
55.
Dominic Deo Androga Ebru Özgür Inci Eroglu Ufuk Gündüz Meral Yücel 《International Journal of Hydrogen Energy》2012
One of the challenges in the development of integrated dark and photofermentative biological hydrogen production systems is the presence of ammonium ions in dark fermentation effluent (DFE). Ammonium strongly inhibits the sequential photofermentation process, and so its removal is required for successful process integration. In this study, the removal of ammonium ions from molasses DFE using a natural zeolite (clinoptilolite) was investigated. The samples were treated with batch suspensions of Na-form clinoptilolite. The ammonium ion concentration could be reduced from 7.60 mM to 1.60 mM and from 12.30 mM to 2.40 mM for two different samples. Photofermentative hydrogen production on treated and untreated molasses DFE samples were investigated in batch photobioreactors by an uptake hydrogenase deleted (hup−) mutant strain of Rhodobacter capsulatus. Maximum hydrogen productivities of 1.11 mmol H2/Lc·h and 1.16 mmol H2/Lc·h and molar yields of 79% and 90% were attained in the treated DFE samples, while the untreated samples resulted in no hydrogen production. The results showed that ammonium ions in molasses DFE could be effectively removed using clinoptilolite by applying a cost-effective, simple batch process. 相似文献
56.
Photofermentative hydrogen production by purple non-sulfur bacteria is a potential candidate among biological hydrogen production methods. Hydrogen is produced under anaerobic conditions in light using different organic substrates as carbon source. The hydrogen evolution occurs mainly through the catalytic activity of the nitrogenases under non-repressive concentrations of ammonia. However, total hydrogen production is constrained due to several reasons in purple non-sulfur (PNS) bacteria, such as consumption of hydrogen by uptake hydrogenase, inefficient hydrogen production capacity of nitrogenase, limited electron flow to the nitrogenase, sensitivity of nitrogenase towards ammonia, etc. Hence, PNS bacteria need to be manipulated genetically to overcome these limitations and to make the process practically feasible. This review focuses on various approaches for the genetic improvement of biohydrogen production by PNS bacteria. 相似文献
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58.
Hamed Dehghanpour Baruj Iklim Bozkaya Betul Canimkurbey Ahmet Tarik Isik Farzan Shabani Savas Delikanli Sushant Shendre Onur Erdem Furkan Isik Hilmi Volkan Demir 《Small (Weinheim an der Bergstrasse, Germany)》2023,19(29):2206582
Semiconductor colloidal quantum wells (CQWs) provide anisotropic emission behavior originating from their anisotropic optical transition dipole moments (TDMs). Here, solution-processed colloidal quantum well light-emitting diodes (CQW-LEDs) of a single all-face-down oriented self-assembled monolayer (SAM) film of CQWs that collectively enable a supreme level of IP TDMs at 92% in the ensemble emission are shown. This significantly enhances the outcoupling efficiency from 22% (of standard randomly-oriented emitters) to 34% (of face-down oriented emitters) in the LED. As a result, the external quantum efficiency reaches a record high level of 18.1% for the solution-processed type of CQW-LEDs, putting their efficiency performance on par with the hybrid organic-inorganic evaporation-based CQW-LEDs and all other best solution-processed LEDs. This SAM-CQW-LED architecture allows for a high maximum brightness of 19,800 cd m−2 with a long operational lifetime of 247 h at 100 cd m−2 as well as a stable saturated deep-red emission (651 nm) with a low turn-on voltage of 1.7 eV at a current density of 1 mA cm−2 and a high J90 of 99.58 mA cm−2. These findings indicate the effectiveness of oriented self-assembly of CQWs as an electrically-driven emissive layer in improving outcoupling and external quantum efficiencies in the CQW-LEDs. 相似文献
59.
Michał Studniarek Ufuk Halisdemir Filip Schleicher Beata Taudul Etienne Urbain Samy Boukari Marie Hervé Charles‐Henri Lambert Abbass Hamadeh Sebastien Petit‐Watelot Olivia Zill Daniel Lacour Loïc Joly Fabrice Scheurer Guy Schmerber Victor Da Costa Anant Dixit Pierre André Guitard Manuel Acosta Florian Leduc Fadi Choueikani Edwige Otero Wulf Wulfhekel François Montaigne Elmer Nahuel Monteblanco Jacek Arabski Philippe Ohresser Eric Beaurepaire Wolfgang Weber Mébarek Alouani Michel Hehn Martin Bowen 《Advanced materials (Deerfield Beach, Fla.)》2017,29(19)
Materials science and device studies have, when implemented jointly as “operando” studies, better revealed the causal link between the properties of the device's materials and its operation, with applications ranging from gas sensing to information and energy technologies. Here, as a further step that maximizes this causal link, the paper focuses on the electronic properties of those atoms that drive a device's operation by using it to read out the materials property. It is demonstrated how this method can reveal insight into the operation of a macroscale, industrial‐grade microelectronic device on the atomic level. A magnetic tunnel junction's (MTJ's) current, which involves charge transport across different atomic species and interfaces, is measured while these atoms absorb soft X‐rays with synchrotron‐grade brilliance. X‐ray absorption is found to affect magnetotransport when the photon energy and linear polarization are tuned to excite Fe? O bonds parallel to the MTJ's interfaces. This explicit link between the device's spintronic performance and these Fe? O bonds, although predicted, challenges conventional wisdom on their detrimental spintronic impact. The technique opens interdisciplinary possibilities to directly probe the role of different atomic species on device operation, and shall considerably simplify the materials science iterations within device research. 相似文献
60.
Emre Alp Emre Can Araz Ahmet Furkan Buluç Yağmur Güner Yücel Değer Halil Eşgin Kamil Burak Dermenci M. Kürşat Kazmanlı Servet Turan Aziz Genç 《Advanced Powder Technology》2018,29(12):3455-3461
Zinc oxide (ZnO) nanostructures with various morphologies have been fabricated in literature owing to their potential applications in various emerging fields. In this study, we report a facile, one-step gram-scale synthesis of nanocrystalline mesoporous ZnO microspheres by thermal decomposition of zinc acetate dihydrate in ethylene glycol at 250?°C for 12?h. The average size of the hollow microspheres is found to be 3.01?±?0.52?µm, which are formed by loosely bonded nanocrystallites with average sizes of 17?±?4?nm. We propose a formation mechanism for the mesoporous microspheres, Ostwald ripening of spherical-like nanocrystallites, on the basis of the results obtained by different synthesis durations. We also report the possibility of tuning the morphologies of the obtained ZnO by simply modifying the thermal decomposition solution, where porous ZnO nanoplates are obtained when a mixture of ethylene glycol and water is used and ZnO nanorods with aspect ratios of ~3 are synthesized by using diethylene glycol. ZnO nanowires with lengths up to several microns are fabricated when no solvent is used, i.e. thermal decomposition in air atmosphere. Microstructural and phase characterizations of the samples are conducted by using a field-emission gun scanning electron microscope and X-ray diffractometer. Performances of the obtained nanocrystalline mesoporous ZnO microspheres in photocatalytic degradation of Rhodamine B and as active anode materials in lithium-ion batteries are also presented. 相似文献