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1.
采用过氧化钠和氢氧化钠高温熔融铬矿石样品,以盐酸溶解熔块,合并溶液后用电感耦合等离子体原子发射光谱法测定样品中硅、铝、镁和铁的含量。选择212.412,308.215,285.213,238.204 nm分别作为硅、铝、镁、铁的分析谱线。用铬矿石标准样品配制标准溶液,对标准溶液的贮存方法进行了研究,对影响标准曲线稳定性的因素进行了讨论。SiO2、Fe2O3、Al2O3和MgO的线性范围依次为0.61%~14.64%,13.62%~27.74%,9.29%~15.17%和9.87%~21.49%。采用该法对铬矿石样品进行30d的连续测定,SiO2、Fe2O3、Al2O3和MgO测定值的相对标准偏差分别在0.51%~1.3%,0.45%~2.0%,0.50%~2.5%和1.4%~2.3%之间。 相似文献
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Russian Journal of Applied Chemistry - Sorption recovery of lanthanum, iron(III), aluminum, and calcium ions from phosphoric acid solutions with MTC 1600 macroporous sulfonic cation exchanger under... 相似文献
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Abdul-Wahab El-Rjoob Ziyad A. Taha Jamil Al-Mustafa Abdulaziz M. Ajlouni 《Journal of solution chemistry》2012,41(7):1079-1087
The formation constants K ML of Clarithromycin (CLA) and Roxithromycin (ROX) with Fe(III) and Fe(II) ions in methanol have been determined at various temperatures using a conductometric technique. The interaction yields complexes with metal-to-ligand compositions of 1:1. The conductivity data were analyzed using a computer program based on 1:1 stoichiometry from which the stability constants and the limiting molar conductance were obtained. The stability of these complexes was found to increase with temperature. Compared with Fe(II), Fe(III) forms more stable complexes with ROX and CLA. The values of the thermodynamic parameters enthalpies (??H °), entropies (??S °), and the derived Gibbs energies (??G °) were deduced from the dependence of the formation constants on temperature. The positive values of ??H ° and ??S ° indicate that the complexation processes is enthalpically unfavorable but entropically favored. The negative values of ??G ° show the ability of the studied ligand to form stable complexes and that the complexation process is favorable. 相似文献
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研究了ICP-AES法测定电镀铬溶液中杂质元素铜、铁、铝、镍含量的方法,对仪器的工作条件、分析线选择、基体影响、共存元素干扰、酸量的影响等进行了试验论证,通过与化学分析方法比较,结果表明方法快速、简便、准确、可靠,完全满足分析要求。 相似文献
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V. P. Yurkinskii E. G. Firsova N. V. Petrova 《Russian Journal of Applied Chemistry》2005,78(8):1370-1372
Complexation of lead(II) ions with hydroxide ions in nitrate-chloride solutions at 298 K was studied using potentiometric titration. 相似文献
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Complexations of crown ethers with alkali metal ions have been investigated extensively by FAB mass spectrometry over the past decade, but very little attention has been paid to reactions of crown ethers with other classes of metal ions such as alkaline earth metal ions, transition metal ions and aluminum ions. Although fast atom bombardment ionization mass spectrometry has proven to be a rapid and convenient method to determine the binding interactions of crown ethers with metal ions, problems in reliabilities for quantitative measurements of” binding strength for the host-guest complexes have been described in the literature. Thus, in this paper, applications of FAB/MS for investigating the complexation of crown ethers with various classes of metal ions is discussed. Extensive fragmentations for neutral losses such as C2H4O or C2H4 molecules from the host-guest complexes could be observed. The reason is attributed to the energetic bombardment processes of FAB occuring in the formation of these complexes. Complexes of cyclen with metal ions also show neutral losses of C2H4NH molecules leading to fragment ions. Transition metal ions usually form (Crown + MCl)+ type of ions, alkaline earth metal ions can form both (Crown + MCl)+ and (Crown + MOH)+ type of ions. But for aluminum ions, only (Crown + Al(OH)2)+ type of ions could he observed. 相似文献
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Complexation of calcium ion with malonic, succinic, glutaric, adipic acids at 25°C, ionic strength I = 0.3 (KCl) was studied by pH-potentiometric titration. 相似文献
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Priya Jaiswal Vijaykumar Ijeri Ashwini Srivastava 《Journal of inclusion phenomena and macrocyclic chemistry》2004,49(3-4):219-224
This paper is a report on the complexation studies of silverions with certain water soluble crown ethers viz., 15-crown-5,18-crown-6, cyclam, diaza 15-crown-5 and certain water insolublecrown ethers viz., benzo 15-crown-5, dibenzodiaza 15-crown-4,dibenzyldiaza 18-crown-6 in some nonionic surfactants viz.,polyoxyethylated alkyl phenol (TX 100), polyoxyethylene (20)sorbiton monolaurate (Tween 20), polyoxyethylene (20) sorbitonmonoleate (Tween 80) and polyoxyethylated glyco monolaurylether (Brij 35) by potentiometry. In addition, conductometry wasalso used to study the complexation of oxa crown ethers to comparethe results obtained by potentiometry, which were found to be ingood agreement with each other. The complexation studies indicate1:1 complex formation between the silver ion and macrocycle, thelogML n+ values being in the range 1 to 9. 相似文献
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Potentiometric titration and IR and UV spectroscopies are used to study complexation of caffeic and ferulic acids by metal ions. Caffeic and ferulic acids, which occur in lignin, are shown to react with metal ions mainly through an ionic mechanism. However, coordination bonding is also possible depending on the nature of the ligand and metal ion and the ratio of starting components. The strongest complex forms between caffeic acid and CuCl
2
(2:1 ratio) 相似文献
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己酸铁对乙醇稀溶液的络合萃取 总被引:1,自引:0,他引:1
乙醇是重要的化工产品,一般通过发酵法和合成法生产,其在发酵液及合成液中的浓度较低[1~3].一些工业过程产生的大量废水中往往含有微量乙醇,需要进行脱除或回收.传统上,乙醇的分离和回收多采用蒸馏法[1,4].但稀溶液蒸馏需要消耗大量的能量.对于含微量醇... 相似文献
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The reaction of Au(Dien)Cl2+ (Dien is diethylenetriamine) with the chloride ion was studied spectrophotometrically in an aqueous solution at I = 1.0 mol/l and T = 20°C. The formation constant of pentacoordinated Au(Dien)Cl 2 + was determined and its spectrum was calculated. 相似文献
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L. A. Grishchenko G. P. Aleksandrova S. A. Medvedeva 《Russian Journal of General Chemistry》2004,74(7):1122-1125
Complexation of Cu(II) with arabinogalactan as influenced by solution pH was studied by spectrophotometry and the method of dialysis equilibrium. Copper ions form complexes with arabinogalactan in a wide pH range, pH 5.0-12.5. Arabinogalactan forms two complex species with the metal. The composition and formation constant of the complex formed at pH <10.8 were determined. 相似文献
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V. N. Lebedev 《Russian Journal of Applied Chemistry》2005,78(12):2032-2034
Conditions in which niobium and tantalum can be separated in the presence of fluoride ions from titanium-containing products formed in processing of loparite were studied. 相似文献
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Z.A El-Hadi 《Journal of solid state chemistry》2002,163(2):351-363
Optical absorption of some selected high-lead borate glasses containing chromium exposed to different doses of gamma-irradiation was studied. The results obtained showed that the absorption bands before and after irradiation exhibited changes with the radiation dose and chemical composition of the glass. The response of the glass to gamma irradiation was related to the creation and spread of defects “color centers,” the approach of a saturation condition after a certain irradiation dose, and the possible photochemical effect on the transition metal present in the glass. 相似文献
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Complexation of some lanthanide ions with poly(methacrylic acid) and its copolymers was studied by potentiometric titration. Poly [methacrylic acid-co-oligo(ethylene oxide)methacrylate] and poly(methacrylic acid-co-acrylamide) formed tris-carboxylate coordinate lanthanide complexes with large overall complexation constants, while poly-(methacrylic acid)s and copolymer with higher content of the methacrylic acid residue formed bis-coordinate ones. It was concluded that the comonomer residues in the copolymer chains decreased the steric hindrance for the complexation and/or acted as co-coordinating groups of the carboxylic group to lanthanide ions. Very large positive and favorable entropy changes were observed for the complexation with poly(methacrylic acid) and its copolymers. This contribution of thermodynamic parameters to the complexation was contrary to that for the analogous monomeric methacrylic acid complex and is assumed to be induced by dehydration of the polymers through the lanthanide ion complexation. 相似文献
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Yurkshtovich N. K. Golub N. V. Kaputskii F. N. Yurkshtovich T. L. Kosterova R. I. 《Russian Journal of Applied Chemistry》2004,77(6):901-904
Sorption of Fe(III), Al(III), and Cr(III) on monocarboxy cellulose at various pH, concentrations of metal chloride or sulfate in solution, and time was studied. The effect of type and amount of the cation sorbed on the physicomechanical properties, swelling, and stability in phosphate buffer of monocarboxy cellulose fibers was considered. 相似文献
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Vasil'ev V. P. Orlova T. D. Balashova T. V. 《Russian Journal of Coordination Chemistry》2002,28(10):706-708
Heats and constants of 15-crown-5 (R) complexation with silver and lead ions at 298, 308, and 318 K are determined using direct calorimetry. Thermodynamic parameters (G°, H°, S°, and C
p°) of formation of AgR+ and PbR2+ complexes at various temperatures are calculated. The effects of the properties of the cations and crown ethers on the thermodynamic parameters of complexation are discussed. 相似文献
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Ergozhin E. E. Chalov A. K. Iskakova R. A. Nikitina A. I. 《Russian Journal of Applied Chemistry》2003,76(2):207-210
Polarography and potentiometry was applied to study the influence exerted by the degree of crosslinking of an ion-exchange resin based on allyl bromide, diglycidil ether of resorcinol, and polyethylenepolyamine on its complexing ability. The shift of the potential of half-wave of reduction of the complex ion and data of potentiometric titration with and without complexing metal were used to calculate the coordination numbers and stability constants of complexes with cations of various metals. 相似文献