共查询到20条相似文献,搜索用时 15 毫秒
1.
T. I. Zhidkova V. V. Belova Yu. Yu. Brenno L. L. Zhidkov A. I. Khol’kin 《Theoretical Foundations of Chemical Engineering》2009,43(5):826-830
We investigated the phase distribution of chloride complex platinum and palladium acids in the presence of the binary extracting agent trioctylmethylammonium dinonylnaphthalenesulfonate. During the extraction of H2PtCl6 and H2PdCl4, the distribution coefficients were found to decrease as long as the pH value was growing, in full accordance with the known general trend of binary extraction. In contrast to the extraction variant using quaternary ammonium bases with inorganic counterions, a binary system, which was based on dinonylnaphthalenesulfonic acid, could be used for the further aqueous reextraction of platinum metals from the organic phase because of the higher thermodynamic stability of the binary reagent in the two-phase system. 相似文献
2.
A novel photocatalytic deposition method for the preparation of a thin tubular palladium membrane is presented in this paper.
The membrane is prepared on a porous asymmetric TiO2 support by photocatalytic reaction of palladium ion, followed by electroless plating. Gas permeation results show that the
membrane exhibits increased hydrogen permeance with the increase of temperature. The hydrogen permeance and selectivity to
nitrogen at 773 K are about 1.43×l0−6 mol m−2 s−1 Pa−1 and 17, respectively, when the pressure in the feed side is 0.1 MPa. The activation energy of hydrogen permeation is 11.06
kJ/mol at the temperature range of 573–773 K. 相似文献
3.
《Diamond and Related Materials》2007,16(3):623-629
Diamond-like hydrogenated carbon films have been formed at low temperatures using methane and acetylene as precursor gases. The source used was of a cascaded arc type employing Ar and Ar/H2 as carrier gases. Energies of ion species and ion densities in the plasma were measured with a mass energy probe and a Langmuir probe.The films produced were characterized in terms of sp3 content, refractive index, relative hydrogen content, hardness and adhesion. The variation of these parameters is presented as functions of precursor gas flow, process pressure, and surface temperature.Deposition rates up to 30 nm/s have been achieved using acetylene as precursor gas at substrate temperatures below 100 °C. Experiments with acetylene showed deposition rates seven times greater than with methane. The typical sp3 content of 55–78% in the films was determined by X-ray-Excited Auger Electron Spectroscopy (XAES) technique. The hardness and reduced modulus were determined by nanoindentation. Preliminary Atomic Force Microscopy (AFM) studies of the films showed a roughness below 3 nm (Ra). 相似文献
4.
The work presents experimental results on silver cementation from spent photographic fixer thiosulphate solutions by iron in magnetically controlled particle beds. Axial magnetic field created by Helmholtz pair was used. The increase in the fluid flow rate yields an increased silver recovery due to reduction in the external mass transfer resistance irrespective of the particle bed structures used for cementation. The field intensity slightly boosts the silver recovery and results in granular structures appearing at the surface of the deposits. The bed structures when the iron is used as a particle beds in column operation has major role in the efficient performance of the cementation process. With flow rate slightly exceeding the minimum fluidization point in the absence of a field the preferable operating regimes are: a fixed bed (FB) and moderately expanded magnetically stabilized beds (MSB) regimes, both of them with the Magnetization FIRST mode. However, when high flow throughputs are required, the frozen beds with the Magnetization LAST exhibit higher separation efficiencies and higher mass transfer coefficients than those with FB and MSB. 相似文献
5.
T. Takei 《Journal of Applied Electrochemistry》1979,9(5):587-593
This paper describes a study of the deposition of lithium from lithium salts (LiNO3, LiCl, and LiClO4) in organic solvents (CH3CN, (CH3)2SO, HCONH2, HCON(CH3)2, CH3CON(CH3)2, and THF) using the potential-sweep technique. The current efficiency for lithium deposition was found to depend on both the solvent used and the particular anion in the electrolyte. In CH3CON(CH3)2, (CH3)2SO, and HCON(CH3)2 solutions, the current efficiency for lithium deposition increased in the order: lithium chloride < lithium perchlorate < lithium nitrate whereas in CH3CN it increased on addition of chloride. Addition of water to the LiNO3-DMF solution also increased the current efficiency for lithium deposition. The solution which gave the highest efficiency was LiNO3 in CH3CON(CH3)2, in which efficiencies higher than 70% were obtained. The lithium metal deposited electrolytically from the LiNO3-HCON(CH3)2 solution consisted of fine grains and had a high degree of crystallinity with very smooth deposit surfaces. 相似文献
6.
Palladium/silica catalysts of varying dispersities were submitted to the coking reaction with cyclopentane at 500°C. Temperature programmed oxidation curves reveal the presence of two peaks for carbon deposition on the metallic function: the first one near 250°C would correspond to coke deposited on palladium atoms of high coordination and the second one near 400°C would involve palladium atoms of low coordination. 相似文献
7.
The initial stages of palladium deposition onto Au(111) from 0.1 M HNO3 + 0.2 mM Pd(NO3)2 have been studied by cyclic voltammetry and in situ scanning tunnelling microscopy. It is demonstrated that nucleation starts exclusively at surface defects such as monoatomic high steps, which is at variance with recently published work. From this and our previous work it thus appears that surface defects are the preferred nucleation sites indeed for nitrate, sulphate and chloride containing solutions. 相似文献
8.
R. G. Robins 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1966,16(6):187-190
Uranium dioxide of high purity has been precipitated directly from acid uranyl nitrate solutions by hydrogen in a stainless steel autoclave at temperatures in the region of 300° and pressures up to 40 atmospheres. The thermodynamics of the reaction are discussed. 相似文献
9.
Olga N. Kononova Alexey N. Lukianov Mikhail V. Derevyashkin Alexander G. Kholmogorov Sergey V. Kachin Natalya G. Goryaeva 《Journal of Porous Materials》2008,15(1):61-66
Sorption recovery of palladium from nitric acid solutions on carbon adsorbents BAU, LKAU-7, ABG and UC has been investigated
using model solutions with concentrations 8 × 10−4–8 × 10−3 mol/l for palladium and 1, 2 and 5 mol/l for nitric acid. The recovery degrees of Pd(II) depend on the concentration of palladium
in contacting solutions as well as on the type of sorbent used. On average, they reach 60%–100% with the maximum in 1 M HNO3 The palladium desorption by 10% thiocarbamide solution in 1M H2SO4 proceeds completely for the sorbent LKAU-7. The use of thiocarbamide solutions in 0.1 M NaOH increases the desorption of
palladium from the sorbents BAU and UC up to 80%–85% 相似文献
10.
Data on cathodic processes in sulphate solutions containing Cu(II) and Sn(II) ions and H2SO4 with and without Laprol 2402C (OA) is given. The sequence of cathodic processes and their dependence on the electrolyte composition were determined. The presence of OA extended the range of cathodic current densities (i
c) at which a high quality alloy was obtained. Electrolysis conditions under which the cathodic process rates considerably decrease were found. This is caused by passivation of the cathode surface by the film formed. The cathode passivation is accompanied by periodic oscillations. Anodic current peaks, i.e. reverse maxima, were found to occur during reverse potential sweeps. The peak values depended on the potential at which the reverse sweep began. 相似文献
11.
C. LIEBENOW 《Journal of Applied Electrochemistry》1997,27(2):221-225
The reversibility of electrochemical magnesium deposition from Grignard reagents was investigated with regard to potential application of magnesium as a negative electrode in rechargeable batteries. The reoxidation rate depends on the morphology of the magnesium deposit which is controlled by the substrate material. Good results were obtained using silver or gold substrates. Magnesium deposits on these materials was found to be of smooth and compact morphology. A nearly complete electrochemical reoxidation and a low self-discharge were observed. 相似文献
12.
Fertilizers containing urea can suffer from nitrogen (N) loss through ammonia volatilization, resulting in reduced effectiveness of the fertilizers. The loss of N may be reduced by use of organic or inorganic additives.Laboratory experiments were conducted on surface soil samples (0–15 cm) from two agricultural soils (St. Bernard and Ste. Sophie) to determine the impact of ammonium thiosulfate (ATS), boric acid, and a humic substance from leonardite, on NH3 losses from surface-applied urea-ammonium nitrate (UAN) solutions. Experiments were carried out using moist soil samples in closed containers. Evolved NH3 was carried out of the containers and trapped in boric acid solution using an ammonia-free humidified air flow.Total NH3 losses in these experiments ranged from 12.1 to 21.3% of the N applied. The reduction in NH3 volatilization (expressed as % of added N) due to additives ranged from 13.6 to 38.5% and 3 to 36.3% in St. Bernard and Ste. Sophie soils, respectively. More NH3 volatilized from the boric acid or humic treated UAN solutions than from ATS-UAN solutions.Boric acid, ATS, and the humic substance, all significantly reduced urea hydrolysis in both soils in comparison to the untreated UAN solution. Further, the humic substance and boric acid treatment induced significant reduction in NO3-formation. The results suggest that humic substance and to a lesser extent boric acid may function as urease and/or nitrification inhibitors. ATS treatment, particularly at higher levels increased NO3-formation in both soils. The reason for this increase in nitrate formation is not clear. 相似文献
13.
《Diamond and Related Materials》2000,9(2):219-223
Hydrogenated diamond powder was treated with an anhydrous chloroform solution of 2,2′-azobisisobutyronitrile as the radical initiator and sulfuryl chloride as the chlorination reagent at 323 K under an Ar atmosphere. After the chlorination process, the solution was exhaustively evaporated, and n-butylamine was added without exposure to air. The diamond was then butylaminated at 303 K for 1–24 h. The treated diamond powder was washed with tetrahydrofuran and water to remove by-products, and characterized by infrared spectroscopy and flash pyrolysis. It could be confirmed that the hydrogenated diamond surface was modified by the radical reactions in the liquid phase. However, the formation of covalent bonds between butylamine groups and carbons on the chlorinated diamond surface did not constitute a major reaction under the conditions of the present study. 相似文献
14.
O. W. J. S. Rutten A. Van Sandwijk G. Van Weert 《Journal of Applied Electrochemistry》1999,29(1):87-92
Cathodic regeneration of nitrous acid by electrochemical reduction of nitrates could yield a catholyte which is useful in the processing of manganiferous ores. The purpose of the present investigations was to study the cathodic reaction in an electrolytic cell with an acidic nitrate electrolyte. Electrochemical reduction of nitrate has been investigated in the ranges 0.45–2.70m H+, 0.0–0.1m HNO2, 0.5–2.0m NO3– and 20–80°C at several cathode materials. Potentiodynamic scanning experiments with a platinized titanium cathode showed limiting current densities of 0–300Am–2 at cathode potentials of +950–+700mV vs SHE. At cathode potentials less than +700mV vs SHE, cathodic reduction of nitrous acid to nitric oxide took place. A linear relation between the nitrous acid concentration and the limiting current density was found in this experimental range. Nitrous acid can be produced by cathodic reduction of nitric acid in a membrane cell. However, the maximum concentration of nitrous acid that can be produced is limited by two reactions; decay of nitrous acid to nitric acid and nitric oxide and cathodic reduction of nitrous acid to nitric oxide. 相似文献
15.
R. E. F. Einerhand W. H. M. Visscher E. Barendrecht 《Journal of Applied Electrochemistry》1988,18(6):799-806
The determination of the amount of hydrogen produced during the electrodeposition of zinc from alkaline zincate solutions was carried out using the rotating ring-disc electrode (RRDE) technique. The experimental conditions for which the RRDE technique offers reliable results are discussed. Hydrogen production during zinc deposition was studied for a range of cathodic (disc) current densities (20–500 A m–2) and electrolyte compositions (1–7 M KOH, 0.01–0.2 M zincate). It was found that an increasing amount of hydrogen was formed with increasing (disc) current density and decreasing KOH and zincate concentration. The impact of hydrogen formation during the charging process on nickel oxide/zinc secondary battery performance is expected to be small. It is concluded that in battery electrolytes (8 M KOH, 1 M zincate) hydrogen is formed chiefly by corrosion of the zinc electrode rather than by electrochemical formation during the electrochemical reduction of zinc. 相似文献
16.
Boron-doped hydrogenated amorphous carbon films grown by surface-wave mode microwave plasma chemical vapor deposition 总被引:1,自引:0,他引:1
Sudip Adhikari Dilip C. Ghimire Hare Ram Aryal Sunil Adhikary Hideo Uchida Masayoshi Umeno 《Diamond and Related Materials》2006,15(11-12):1909
We report the effects of boron (B) doping on optical and structural properties of the hydrogenated amorphous carbon thin films grown by surface-wave mode microwave plasma (SW-MWP) chemical vapor deposition (CVD) on n-type silicon and quartz substrates at room temperature. Argon and acetylene were used as a carrier and carbon source gases respectively. Analytical methods such as X-ray photoelectron spectroscopy (XPS), Nanopics 2100/NPX200 surface profiler, JASCO V-570 UV/VIS/NIR spectroscopy, Fourier transform infrared spectroscopy (FT-IR) and Raman spectroscopy were employed to investigate the properties of the films. Low atomic concentration of B (0.08 at.%) was found in the doped film. The optical band gap of the undoped film was 2.6 eV and it decreased to 1.9 eV for the B-doped film. Structural property shows the crystalline structure of the film and it has changed after incorporating B as a dopant. The structural modifications of the films leading to being more graphite in nature were confirmed by the Raman and FT-IR characterization. 相似文献
17.
S. Sánchez‐Valdes E. Ramírez‐Vargas H. Ortega‐Ortiz L. F. Ramos‐deValle J. Méndez‐Nonell M. Mondragón‐Chaparro G. Neira‐Velázquez I. Yañez‐Flores D. E. Meza‐Rojas T. Lozuno‐Ramirez 《应用聚合物科学杂志》2012,123(5):2643-2650
Silver nanoparticles were deposited on the surface of the external polyamide 6 (PA6) layer of a multilayer film, by spraying and ultrasound‐assisted methods. The effect of silver nanoparticles content and deposition method on the mechanical and optical properties of the multilayered films as well as the efficiency of silver ion release and their fungicidal characteristics were evaluated. Itaconic (IA) and Maleic anhydride (MA) were used as adhesion promoter agents for preventing the agglomeration of the silver nanoparticles and for improving the adhesion to the PA6 polymer surface. With IA, a homogeneous distribution of silver nanoparticles on the PA6 surface was achieved. The silver ion release and biocide effect of the multilayered films was found to be dependent on the anhydride type and on the deposition method used. The multilayer films with a layer of PA6‐silver nanocomposite demonstrated good fungicidal activity, specifically against fungus Aspergillius niger. The observed results could be applied in the design of industrial films for packaging. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 相似文献
18.
Javier M. Grau Jos M. Bisang 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1995,62(2):153-158
This paper deals with the use of iron felt as a reducing agent for the removal of mercury from aqueous dilute solutions containing chloride ions. The kinetic behavior of the mercuric ion reduction was analyzed and its diffusion coefficient was determined with the use of a rotating disk electrode. Experimental results of the removal of mercury from aqueous sodium chloride solutions containing 100 ppm mercury by contact with iron felt are reported. The mercury concentration was decreased to values lower than 0·1 ppm. The recovery of metallic mercury by chemical attack of the residual iron felt was also analyzed. 相似文献
19.
对光催化沉积法(PCD)制备Pd膜进行了改进,使含有TiO2与Pd2 的悬浮液膜层在多孔陶瓷膜表面形成液体薄膜,该薄膜在紫外光直接照射下发生光催化还原反应,烧结后得到含TiO2及Pd晶种的超薄膜层,用化学镀修饰得致密Pd膜.采用SEM、EDAX方法对所制的Pd膜表征结果表明,Pd膜厚度为5~6μm.在350~500℃和0.05~0.15 MPa下进行气体渗透实验,当温度为450℃时,H2渗透系数为4.07×10-6mol/(m2.s.Pa),N2的渗透量检测不出,高温热循环测试表明该Pd膜致密且具有良好的热稳性. 相似文献
20.
Reza Katal Sara Pourkarimi Ehsan Bahmani Hamed Aleebrahim Dehkordi Mohhamad Ali Ghayyem Hussein Esfandian 《乙烯基与添加剂工艺杂志》2013,19(2):147-156
The aim of this work was to investigate the sorption characteristics of Fe3O4 coated on polyaniline (Fe3O4/PAn) for the removal of NO3? ions from aqueous solutions. The sorption of NO3? ions by the batch method was carried out. The optimum conditions of sorption were found to be a Fe3O4/PAn dose of 0.4 g in 100 mL of NO3? solution, a contact time of 10 min, pH and temperature 7 and 40°C, respectively. Temperature had a negative effect on the removal efficiency. Three equations, i.e., Morris–Weber, Lagergren, and pseudo‐second‐order, were tested to track the kinetics of the removal process. The Langmuir, Freundlich, and Dubinin–Radushkevich isotherm models were subjected to sorption data in order to estimate sorption capacity, intensity, and energy. The thermodynamic parameters ΔH, ΔS, and ΔG were evaluated. They showed that the adsorption of NO3? onto Fe3O4/PAn was feasible, spontaneous, and exothermic under the studied conditions. It can be concluded that Fe3O4/PAn has potential to remove NO3? ions from aqueous solutions at different concentrations. The system Fe3O4/Pan was successfully tested for a high removal efficiency of NO3? from urban wastewater. J. VINYL ADDIT. TECHNOL., 19:147–156, 2013. © 2013 Society of Plastics Engineers 相似文献