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91.
Dr. Guo‐Qiang Kong Zhi‐Da Han Dr. Yabing He Sha Ou Dr. Wei Zhou Prof. Dr. Taner Yildirim Prof. Dr. Rajamani Krishna Dr. Chao Zou Prof. Dr. Banglin Chen Prof. Dr. Chuan‐De Wu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(44):14886-14894
Two new organic building units that contain dicarboxylate sites for their self‐assembly with paddlewheel [Cu2(CO2)4] units have been successfully developed to construct two isoreticular porous metal–organic frameworks (MOFs), ZJU‐35 and ZJU‐36, which have the same tbo topologies (Reticular Chemistry Structure Resource (RCSR) symbol) as HKUST‐1. Because the organic linkers in ZJU‐35 and ZJU‐36 are systematically enlarged, the pores in these two new porous MOFs vary from 10.8 Å in HKUST‐1 to 14.4 Å in ZJU‐35 and 16.5 Å in ZJU‐36, thus leading to their higher porosities with Brunauer–Emmett–Teller (BET) surface areas of 2899 and 4014 m2 g?1 for ZJU‐35 and ZJU‐36, respectively. High‐pressure gas‐sorption isotherms indicate that both ZJU‐35 and ZJU‐36 can take up large amounts of CH4 and CO2, and are among the few porous MOFs with the highest volumetric storage of CH4 under 60 bar and CO2 under 30 bar at room temperature. Their potential for high‐pressure swing adsorption (PSA) hydrogen purification was also preliminarily examined and compared with several reported MOFs, thus indicating the potential of ZJU‐35 and ZJU‐36 for this important application. Studies show that most of the highly porous MOFs that can volumetrically take up the greatest amount of CH4 under 60 bar and CO2 under 30 bar at room temperature are those self‐assembled from organic tetra‐ and hexacarboxylates that contain m‐benzenedicarboxylate units with the [Cu2(CO2)4] units, because this series of MOFs can have balanced porosities, suitable pores, and framework densities to optimize their volumetric gas storage. The realization of the two new organic building units for their construction of highly porous MOFs through their self‐assembly with [Cu2(CO2)4] units has provided great promise for the exploration of a large number of new tetra‐ and hexacarboxylate organic linkers based on these new organic building units in which different aromatic backbones can be readily incorporated into the frameworks to tune their porosities, pore structures, and framework densities, thus targeting some even better performing MOFs for very high gas storage and efficient gas separation under high pressure and at room temperature in the near future. 相似文献
92.
Amidoxime modified hydroxypropyl methylcellulose (HPMC) films (HPMC-g-AO) were used for the recovery of uranium from aqueous solutions by a complexation process. The adsorption experiments were carried out by immersion of a certain amount of films in UO2 2+ solutions (resultant pH 4.1) ranging in concentration from 100 to 1,000 ppm. The effect of temperature (25–50 °C) on the adsorption capacity of HPMC-g-AO was investigated at the optimized time. The adsorption kinetics and the thermodynamics as well as the adsorption capacity of HPMC-g-AO films were investigated. The adsorption capacity was found as 765 mg UO2 2+/g dry film. The kinetic and the thermodynamic parameters (i.e. activation energy, enthalpy, entropy and Gibbs free energy) for the interaction of UO2 2+ with HPMC-g-AO were calculated based on known basic relations. The results showed that adsorption occurred through strong electrostatic interactions with an enthalpy of ?36.5 kJ/mol. The desorption of UO2 2+ were investigated using different desorption agents such as EDTA, HCl, NaHCO3, and NaOH. After the 2 weeks treatment period, the highest desorption yield were found as 23 % with NaHCO3. 相似文献
93.
Na[cyclo‐(P5tBu4)] ( 1 ) reacts with [FeBr2(CO)4] (2:1) to give the first homoleptic iron(II) complex [Fe{cyclo‐(P5tBu4)}2] ( 2 ) containing two tridentate cyclo‐(P5tBu4)– ligands. Thermolysis of 2 up to 500 °C produces a new phosphorus‐rich iron phosphide, calculated as FeP6 according to the mass change. 相似文献
94.
Gamze Karayel Incili Gul Asiye Aycık 《Journal of Radioanalytical and Nuclear Chemistry》2014,301(2):417-426
Schiff base hydrazone derivative (HL) sorbent was synthesized according to the literature to be used in the adsorption and preconcentration of U(VI) ions from aqueous solution and it was exposed to immobilization, and new solid support material was obtained. For this purpose, Schiff base hydrazone derivative (HL) was chemically bonded to silica gel surface immobilized 3-aminopropyl trimethoxysilane, then analyzed by Fourier transform infrared, Brunauer–Emmett–Teller, scanning electron microscopy and elemental analysis. The influence of the solution pH, amount of sorbent, contact time, temperature, foreign ion effect and initial U(VI) concentration was investigated. The maximum U(VI) uptake capacity was found to be 8.46 mg/g. 相似文献
95.
Simultaneous determination of seven phthalic acid esters in beverages using ultrasound and vortex‐assisted dispersive liquid–liquid microextraction followed by high‐performance liquid chromatography
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Pelin Köseoğlu Yılmaz Abdulselam Ertaş Ufuk Kolak 《Journal of separation science》2014,37(16):2111-2117
A sensitive, rapid, and simple high‐performance liquid chromatography with UV detection method was developed for the simultaneous determination of seven phthalic acid esters (dimethyl phthalate, dipropyl phthalate, di‐n‐butyl phthalate, benzyl butyl phthalate, dicyclohexyl phthalate, di‐(2‐ethylhexyl) phthalate, and di‐n‐octyl phthalate) in several kinds of beverage samples. Ultrasound and vortex‐assisted dispersive liquid–liquid microextraction method was used. The separation was performed using an Intersil ODS‐3 column (C18, 250 × 4.6 mm, 5.0 μm) and a gradient elution with a mobile phase consisting of MeOH/ACN (50:50) and 0.2 M KH2PO4 buffer. Analytes were detected by a UV detector at 230 nm. The developed method was validated in terms of linearity, limit of detection, limit of quantification, repeatability, accuracy, and recovery. Calibration equations and correlation coefficients (> 0.99) were calculated by least squares method with weighting factor. The limit of detection and quantification were in the range of 0.019–0.208 and 0.072–0.483 μg/L. The repeatability and intermediate precision were determined in terms of relative standard deviation to be within 0.03–3.93 and 0.02–4.74%, respectively. The accuracy was found to be in the range of –14.55 to 15.57% in terms of relative error. Seventeen different beverage samples in plastic bottles were successfully analyzed, and ten of them were found to be contaminated by different phthalic acid esters. 相似文献
96.
Vibration analysis of cracked beams having linearly varying cross-sections both in thickness and width was investigated. A computer program using the finite element method has been written to find the dynamical characteristics (natural frequencies and mode shapes) of the cracked beam. The cracked section in the beam has been modeled by a massless spring whose flexibility depens on the local flexibility induced by the crack. The stiffness of spring has been derived from the linear elastic fracture mechanics theory as the inverse of the compliance matrix calculated using stress intensity factors and strain energy release rate expression. Some examples have been given to explain the proposed method and investigate the effects of the depth and location of cracks on the natural frequencies and mode shapes. The results of current study and those in the literature are compared and good agreements have been found. Consequently it is showed that proposed method is reliable and simple. (© 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
97.
Bayrakdar Alpaslan Mert Samet Kasımoğulları Rahmi Bangaru Sathya Manivannan Prasath 《Research on Chemical Intermediates》2022,48(5):2087-2109
Research on Chemical Intermediates - Trifluoromethyl group containing pyrazole-3-carboxamide derivative is synthesized and the structure of the molecule (E3N5PC) has been verified by using FT-IR,... 相似文献
98.
A comparison of the analytical performances of four different (bio)sensor designs in H2O2 determination is discussed. The (bio)sensor designs developed were based on the use of (i) multiwalled carbon nanotubes (MWCNT), zinc oxide nanoparticles (ZnONP), prussian blue (PB); (ii) MWCNT, ZnONP, PB and ionic liquid (IL); (iii) MWCNT, ZnONP and horseradish peroxidase (HRP) and (iv) MWCNT, ZnONP, HRP and IL modified glassy carbon electrode (GCE). A performance comparison of (bio)sensors showed that the one based on HRP/IL-MWCNT-ZnONP/GCE showed the best analytical characteristics with a linear dynamic range of 9.99×10−8–7.55×10−4 M, detection limit of 1.37×10−8 M and sensitivity of 17.00 μA mM−1. 相似文献
99.
Hemn A. H. Barzani Hoshyar Saadi Ali Cihat Şahin Musa Kıran Yavuz Yardım 《Electroanalysis》2022,34(8):1280-1288
An effective electrochemical sensor was constructed using an unmodified boron-doped diamond electrode for determination of genistein by square-wave voltammetry. Cyclic voltammetric investigations of genistein with HClO4 solution indicated that irreversible behavior, adsorption-controlled and well-defined two oxidation peaks at about +0.92 (PA1) & +1.27 V (PA2). pH, as well as supporting electrolytes, are important in genistein oxidations. Quantification analyses of genistein were conducted using its two oxidation peaks. Using optimized experiments as well as instrumental conditions, the current response with genistein was proportionately linear in the concentrations range of 0.1 to 50.0 μg mL−1 (3.7×10−7−1.9×10−4 mol L−1), by the detection limit of 0.023 μg mL−1 (8.5×10−8 mol L−1) for PA1 and 0.028 μg mL−1 (1.1×10−7 mol L−1) for PA2 in 0.1 mol L−1 HClO4 solution (in the open circuit condition at 30 s accumulation time). Ultimately, the developed method was effectively applied to detect genistein in model human urine samples by using its second oxidation peak (PA2). 相似文献
100.
This paper describes a novel approach to detect Cd(II) using the combination of the differential pulse anodic stripping voltammetry and magnetic nanoparticle based dispersive solid phase microextraction as an efficient, green and accurate method. Currents of Cd(II) increased linearly in the range from 75 to 2000 ng L−1 Cd(II) with a detection limit of 21.6 ng L−1. The RSD values of 2.6 and 6.0 % for 1.00 and 0.10 μg L−1 respectively showed that proposed method has an acceptable repeatability. Recovery values between 92.3 and 98.6 % showed that this approach can be successfully used for determination of Cd(II) in water samples. 相似文献