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1.
A comparative study of the effect of 1-butyl-3-methylimidazolium hydrogen sulfate-[BMIM]HSO4 and gelatine on current efficiency (CE), power consumption (PC), deposit morphology, and polarization behaviour of the cathode
during electrodeposition of zinc from acidic sulphate solutions were investigated. Compared with the traditional industrial
additive, gelatine, the addition of [BMIM]HSO4 was found to increase current efficiency, reduce power consumption, and improve the surface morphology. Maximum CE and minimum
PC were obtained at the addition dosage of 5 mg dm−3. Meanwhile, simultaneous addition of the two additives induced a blocking effect of the zinc reduction and led to more leveled
and fine-grained cathodic deposits. Moreover, cyclic voltammetry results and kinetic parameters such as Tafel slope, transfer
coefficient, and exchange current density obtained from Tafel plots led to the conclusion that both additives have a pronounced
inhibiting effect on Zn2+ electroreduction. The data obtained from X-ray diffractogram revealed that the presence of additives did not change the structure
of the electrodeposited zinc but affected the crystallographic orientation of the crystal planes. 相似文献
2.
Qi Bo Zhang Yi Xin Hua Tie Guang Dong Dan Gui Zhou 《Journal of Applied Electrochemistry》2009,39(8):1207-1216
The effects of temperature and current density on cathodic current efficiency, specific energy consumption, and zinc deposit
morphology during zinc electrodeposition from sulfate electrolyte in the presence of 1-butyl-3-methylimidazolium hydrogen
sulfate ([BMIM]HSO4) as additive were investigated. The highest current efficiency (93.7%) and lowest specific energy consumption (2,486 kWh t−1) were achieved at 400 A m−2 and 313 K with addition of 5 mg dm−3 [BMIM]HSO4. In addition, the temperature dependence of some kinetic parameters for the zinc electrodeposition reaction was experimentally
determined. Potentiodynamic polarization sweeps were carried out to obtain the expression for each parameter as a function
of temperature. In the condition studied, the exchange current density depended on temperature as ln(i
0) = −a/T + b and the charge transfer coefficient was constant. Moreover, the adsorption of the additive on cathodic surface obeyed the
Langmuir adsorption isotherm. The associated thermodynamic parameters indicated the adsorption to be chemical. 相似文献
3.
The effects of ionic liquid additive 1-butyl-3-methylimidazolium hydrogen sulfate-[BMIM]HSO4 on the current efficiency (CE), surface morphology, and crystallographic orientations during zinc electrodeposition from
acidic sulfate solutions containing some common impurities such as copper, iron, cobalt, nickel, and lead were investigated.
The results indicated that all the metallic impurities studied exerted a deleterious effect on the zinc electrodeposition
process by decreasing the CE, influencing the purity, and inducing changes in morphology of the cathodic deposits. The addition
of [BMIM]HSO4 was observed to relieve the harmful effects of these impurities to some extent, and led to reduce the impurity content in
the zinc deposits and improve the CE and the quality of the cathodic deposits. The data obtained from X-ray diffraction revealed
that the presence of these impurities alone and in combination with [BMIM]HSO4 did not change the structure of the electrodeposited zinc but affected the crystallographic orientation of the crystal planes. 相似文献
4.
The nucleation and first stages of the growth of zinc on aluminum from acidic sulfate solution in the absence and presence
of 1-butyl-3-methylimidazolium hydrogen sulfate-[BMIM]HSO4 as additive were investigated using cyclic voltammetry, chronoamperometric current–time transients, and scanning electron
microscopy techniques. The dimensionless chronoamperometric current–time transients for the zinc electrodeposition on aluminum
electrode from the solution free of [BMIM]HSO4 showed the zinc deposition can be interpreted by a model involving instantaneous nucleation with hemispherical diffusion
controlled growth of nuclei. The addition of [BMIM]HSO4 induced a blocking effect on the zinc electrocrystallization process through its cathodic adsorption on the electrode surface.
This effect led to increase the number density of active sites, decrease the nucleation and growth rate of these nuclei, and
produce more leveled and fine-grained cathodic deposits without affecting the instantaneous nucleation mechanism. Surface
morphology analysis revealed the crystal structure of the zinc deposits formed did not change by the adsorption of [BMIM]HSO4 at the first stages of deposition. 相似文献
5.
The effects of the organic additives 1-hexyl-3-methylimidazolium hydrogen sulfate ([HMIM]HSO4) and 1-octyl-3-methylimidazolium hydrogen sulfate ([OMIM]HSO4) on current efficiency (CE), power consumption (PC), polarization behavior of the cathode, deposit morphology, and crystallographic
orientation during electrodeposition of zinc from acidic sulfate solution were investigated. The results were compared with
those of a common industrial additive, gum arabic. Addition of these additives increases current efficiency, decreases power
consumption, and improves the surface morphology at lower concentrations. Both the additives showed similar polarization behavior
to gum arabic and the extent of polarization was in the order: gum arabic > [OMIM]HSO4 > [HMIM]HSO4. The nature of the electrode reactions was studied through measurements of Tafel slopes, transfer coefficients, and exchange
current densities. Data obtained from X-ray diffractogram revealed that the presence of any of these additives did not change
the structure of the electrodeposited zinc but affected the crystallographic orientation of the crystal planes. 相似文献
6.
《Catalysis communications》2008,9(3):337-341
Prins reaction, used to prepare dioxanes, has been limited by complex catalyst separation and reusability. In this article, six water-stable Brønsted acidic task-specific ionic liquids ([HMIM]BF4,[(CH2)4SO3HMIM][HSO4], [(Ac)2BIM]Br, [NMP][HSO4], [BMIM][HSO4] and [BMIM][H2PO4] were synthesized and used as environmentally benign catalysts for Prins reaction under mild reaction conditions for the first time. The process is highly effective and environmentally benign. Furthermore, [BMIM][HSO4] was conveniently separated with the products and easily recycled to catalyze Prins reaction again with excellent yields. 相似文献
7.
Shweta J. Malode Nagaraj P. Shetti Sharanappa T. Nandibewoor 《Catalysis Letters》2011,141(10):1526-1540
Abstract
The kinetics of osmium(VIII) (Os(VIII)) and ruthenium(III) (Ru(III)) catalysed oxidation of l-valine (l-val) by diperiodatoargentate(III) (DPA) in aqueous alkaline medium at 25 °C and a constant ionic strength of 0.006 mol dm−3 was studied spectrophotometrically. The stoichiometry is the same in both the catalysed reactions, i.e., [l-val]:[DPA] = 1:1. The reaction is of first order in [Os(VIII)], [Ru(III)], and [DPA] and has less than unit order in [l-val] and negative fractional order in [OH−]. Added periodate had no effect on rate of reaction. The products were identified by spot test and characterized by spectral studies. The catalytic constant (K C) was also calculated for both catalysed reactions at different temperatures. The activation parameters with respect to slow step of the mechanisms were computed and discussed and thermodynamic quantities were also determined. It has been observed that the catalytic efficiency for the present reaction is in the order of Os(VIII) > Ru(III). The probable active species of catalyst and oxidant have been identified. 相似文献8.
S. T. Aruna V. K. William Grips K. S. Rajam 《Journal of Applied Electrochemistry》2010,40(12):2161-2169
Electrodeposited Ni–Al2O3 composite coatings were prepared using alumina powders synthesized from solution combustion method, precipitation method
and a commercial source. Solution combustion synthesized alumina powder yielded α-phase; precipitation method yielded purely
γ-phase; commercial alumina powder was a mixture of α-, δ- and γ-phases. A nickel sulfamate bath was used for electro-codeposition.
The current densities (0.23 A dm−2 for 20 h, 0.77 A dm−2 for 6 h, 1.55 A dm−2 for 3 h and 3.1 A dm−2 for 1.5 h) and bath agitation speeds (100, 200, 600 and 1000 rpm) were varied. The pH variations of the bath were higher
during the electrodeposition of combustion synthesized alumina. The effect of different forms of alumina particles on the
microhardness and microstructure of the nickel composite coating was studied. Composite coating containing combustion synthesized
alumina particles was found to have higher microhardness (550 HK). It was found that at lower agitation speed (100 rpm), bigger
particles were incorporated and at higher agitation speed (1000 rpm), smaller particles were incorporated. The area fraction
of alumina particles incorporated in nickel matrix was highest for commercial alumina (24%). This study shows that it is not
suffice to take just the current density and stirring speeds into account to explain the properties of the coatings but also
to take into account the source of particles and their properties. 相似文献
9.
Clarissa P. Frizzo Mara R.B. Marzari Lilian Buriol Dayse N. Moreira Fernanda A. Rosa Pmela S. Vargas Nilo Zanatta Helio G. Bonacorso Marcos A.P. Martins 《Catalysis communications》2009,10(15):1967-1970
In order to evaluate the effect of a series of 10 different ionic liquids ([BMIM][BF4], [BMIM][Br], [OMIM][BF4], [BMIM][PF6], [DBMIM][Br], [DBMIM][BF4], [BMIM][OH], [BMIM][SCN], [HMIM][HSO4] and [HMIM][CF3CO2]) the cyclocondensation reaction between 4-dimethylamino-1-phenyl-3-alken-2-ones (RC(O)CHCHNMe2, where R = Ph, 4-Me-Ph, 4-F-Ph, 4-Cl-Ph, 4-Br-Ph, 4-NO2-Ph, thien-2-yl, fur-2-yl, pyrrol-2-yl, pyrid-2-yl, hexyl, dimethoxymethyl) and tert-butylhydrazine was performed. The effects of each ionic liquid are discussed and the best yields for the cyclocondensation reaction studied were obtained using [BMIM][BF4]. 相似文献
10.
《Catalysis communications》2010,11(15):1967-1970
In order to evaluate the effect of a series of 10 different ionic liquids ([BMIM][BF4], [BMIM][Br], [OMIM][BF4], [BMIM][PF6], [DBMIM][Br], [DBMIM][BF4], [BMIM][OH], [BMIM][SCN], [HMIM][HSO4] and [HMIM][CF3CO2]) the cyclocondensation reaction between 4-dimethylamino-1-phenyl-3-alken-2-ones (RC(O)CHCHNMe2, where R = Ph, 4-Me-Ph, 4-F-Ph, 4-Cl-Ph, 4-Br-Ph, 4-NO2-Ph, thien-2-yl, fur-2-yl, pyrrol-2-yl, pyrid-2-yl, hexyl, dimethoxymethyl) and tert-butylhydrazine was performed. The effects of each ionic liquid are discussed and the best yields for the cyclocondensation reaction studied were obtained using [BMIM][BF4]. 相似文献
11.
Q.B. Zhang 《Electrochimica acta》2009,54(6):1881-620
The acid corrosion inhibition process of mild steel in 1 M HCl by 1-butyl-3-methylimidazolium chlorides (BMIC) and 1-butyl-3-methylimidazolium hydrogen sulfate ([BMIM]HSO4) has been investigated using electrochemical impedance, potentiodynamic polarization and weight loss measurements. Potentiodynamic polarization studies indicate the studied inhibitors are mixed type inhibitors. For both inhibitors, the inhibition efficiency increased with increase in the concentration of the inhibitor and the effectiveness of the two inhibitors are in the order [BMIM]HSO4 > BMIC. The adsorption of the inhibitors on mild steel surface obeyed the Langmuir's adsorption isotherm. The effect of temperature on the corrosion behavior in the presence of 5 × 10−3 M of inhibitors was studied in the temperature range of 303-333 K. The associated activation energy of corrosion and other thermodynamic parameters such as enthalpy of activation (ΔH), entropy of activation (ΔS), adsorption equilibrium constant (Kads) and standard free energy of adsorption (ΔGads) were calculated to elaborate the mechanism of corrosion inhibition. 相似文献
12.
Shangde Sun Xiaowei Chen Yanlan Bi Jingnan Chen Guolong Yang Wei Liu 《Journal of the American Oil Chemists' Society》2014,91(5):759-765
Feruloyl Glycerol (FG) is a potential antioxidant and UV absorbing ingredient in food and cosmetic industries. Transesterifications of ethyl ferulate (EF) with glycerol to synthesize FG were performed using different functionalized ionic liquids (1‐butylsulfonic‐3‐methylimidazolium tosylate, [BSO3HMIM]TS; 1‐propylsulfonic‐3‐methylimidazolium tosylate, [PSO3HMIM]TS; 1‐butylsulfonic‐3‐methylimidazolium trifluoromethanesulfonate, [BSO3HMIM]OTF; 1‐butylsulfonic‐3‐methylimidazolium hydrogen sulfate, [BSO3HMIM]HSO4; N‐methylimidazolium hydrogen sulfate, [HMIM]HSO4; 1‐butyl‐3‐methylimidazolium hydroxide, [BMIM]OH; 1‐butyl‐3‐methylimidazo tetrachloride molysite, [BMIM]FeCl4; and 1‐hexyl‐3‐methylimidazo tetrachloride molysite, [BMIM]FeCl4) as catalysts, respectively. High EF conversion (98.0 ± 1.5 %), 1‐FG (1‐feruloyl‐sn‐glycerol) yield (88.7 ± 1.1 %) and reaction selectivity for 1‐FG (90.5 ± 2.1 %) were obtained using [BSO3HMIM]TS as catalyst. The activation energy (Ea), the Michaelis–Menten kinetic constant (Km), and the maximum initial reaction rate (vmax) of the transesterification are 65.9 ± 3.3 kJ/mol, 1.8 ± 0.1 mol/L, and (1.6 ± 0.4) × 10?2 mol/(L min), respectively. Effects of catalyst loading, reaction temperature, and the molar ratio of EF to glycerol on EF conversion and reaction selectivity for 1‐FG (1‐FG yield/EF conversion) were also investigated. 相似文献
13.
Noureddine Belhadj Tahar Ridha Abdelhédi André Savall 《Journal of Applied Electrochemistry》2009,39(5):663-669
This paper deals with the treatment of aqueous phenol solutions using an electrochemical technique. Phenol can be partly eliminated
from aqueous solution by electrochemically initiated polymerisation. Galvanostatic electrolyses of phenol solutions at concentration
up to 0.1 mol dm−3 were carried out on a Ta/PbO2 anode. The polymers formed are insoluble in acidic medium but soluble in alkaline. These polymers were filtered and then
dissolved in aqueous solution of sodium hydroxide (1 mol dm−3). The polymers formed were quantified by total organic carbon (TOC) measurement. It was found that the conversion of phenol
into polymers increases as a function of initial concentration, anodic current density, temperature, and solution pH. The
percentage of phenol polymerised can reach 15%. 相似文献
14.
Weiyong Zou Li Wang Baoyi Lu Hong Li Hongyu Chen 《Journal of Applied Electrochemistry》2009,39(10):2015-2020
The electrochemical assembly of [Ru(bpy)2tatp]2+ (where bpy = 2,2′-bipyridine, tatp = 1,4,8,9-tetra-aza-triphenylene) on the multi-walled carbon nanotubes-modified glassy
carbon electrode (MWNTs/GC) in the presence of anionic and cationic surfactants has been investigated. A diffusion-controlled
wave and three prewaves are exhibited on the differential pulse voltammogram of [Ru(bpy)2tatp]2+. The formal potential of the prewaves is found to be much negative than that of the diffusion-controlled wave. An appropriate
amount of anionic surfactants including dihexadecyl phosphate (DHP) and deoxyribonucleic acid (DNA) can prompt the assembly
of [Ru(bpy)2tatp]2+ on the MWNTs/GC electrode by using the method of repetitive voltammetric sweeping. In contrast, cationic surfactant such
as hexadecyl trismethyl ammonium chrolide (HTAC) dispersed on the MWNTs surface is found to inhibit the assembly of [Ru(bpy)2tatp]2+. Meanwhile, the assembled principle of [Ru(bpy)2tatp]2+ on the MWNTs/GC electrode with the participation of surfactants is discussed in detail. 相似文献
15.
N. Papastefanakis D. Mantzavinos A. Katsaounis 《Journal of Applied Electrochemistry》2010,40(4):729-737
The electrochemical oxidation of olive mill wastewater (OMW) over a Ti/RuO2 anode was studied by means of cyclic voltammetry and bulk electrolysis and compared with previous results over a Ti/IrO2 anode. Experiments were conducted at 300–1,220 mg L−1 initial chemical oxygen demand (COD) concentrations, 0.05–1.35 V versus SHE and 1.39–1.48 V versus SHE potential windows,
15–50 mA cm−2 current densities, 0–20 mM NaCl, Na2SO4, or FeCl3 concentrations, 80 °C temperature, and acidic conditions. Partial and total oxidation reactions occur with the overall rate
being near first-order kinetics with respect to COD. Oxidation at 28 Ah L−1 and 50 mA cm−2 leads to quite high color and phenols removal (86 and 84%, respectively), elimination of ecotoxicity, and a satisfactory
COD and total organic carbon reduction (52 and 38%, respectively). Similar performance can be achieved at the same charge
(28 Ah L−1) using lower current densities (15 mA cm−2) but in the presence of various salts. For example, COD removal is less than 7% at 28 Ah L−1 in a salt-free sample, while addition of 20 mM NaCl results in 54% COD reduction. Decolorization of OMW using Ti/RuO2 anode seems to be independent of the presence of salts in contrast with Ti/IrO2 where addition of NaCl has a beneficial effect on decolorization. 相似文献
16.
Li ion conducting polymer electrolyte films were prepared based on poly(vinyl alcohol) (PVA) with 5, 10, 15, 20, 25 and 30 wt%
lithium iron phosphate (LiFePO4) salt using a solution-casting technique. X-ray diffraction (XRD) was used to determine the complexation of the polymer with
LiFePO4 salt. Differential scanning (DSC) calorimetry was used to determine the melting temperatures of the pure PVA and complexed
films. The maximum ionic conductivity was found to be 1.18 × 10−5 S cm−1 for (PVA:LiFePO4) (75:25) film, which increased to 3.12 × 10−5 S cm−1 upon the addition of propylene carbonate (PC) plasticizer at ambient temperature. The Li+ ion transport number was found to be 0.40 for (PVA: LiFePO4) (75:25) film using AC impedance and DC polarization methods. Dielectric studies were performed for these polymer electrolyte
films in the frequency range of 10 Hz to 10 MHz at different temperatures. The activation energies of the complexed films
were calculated from the dielectric loss tangent spectra and were found to be 0.35, 0.30, 0.27 and 0.28 eV. The cyclic voltammogram
(CV) curves of (PVA: LiFePO4) (75:25)+PC film exhibited higher specific capacities than those for other films. 相似文献
17.
《Journal of Industrial and Engineering Chemistry》2014,20(3):759-766
Liquid phase dehydration of glycerol to acrolein catalyzed by Brønsted acidic ionic liquids (BAILs) using semi-batch reaction technique was investigated. For the BAILs catalysts, the acrolein yields were in an order of [Bmim]H2PO4 > [Bmim]HSO4 > [BPy]HSO4 > [PSPy]HSO4 > [N2224]HSO4 > [PSPy]H2PO4 > [BPy]H2PO4 > [N2224]H2PO4. When [Bmim]H2PO4 and [Bmim]HSO4 were used as the catalysts at 270 °C with the molar ratio of catalyst to glycerol of 1:100, the acrolein yields were 57.4% and 50.8%, respectively, at complete conversion of glycerol. The BAILs with [Bmim] cation and moderate acidity favored the formation of acrolein in liquid phase glycerol dehydration. 相似文献
18.
In this study, we synthesized a new hybrid material using well-Dawson K6[P2Mo18O62]·nH2O and a room temperature ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4]). CHN elemental analysis showed that one mole of [P2Mo18O62]6− reacts with 6 moles of [BMIM]+ to form [BMIM]6P2Mo18O62. FT-IR spectra showed the presence of both 1-butyl-3-methylimidazolium cation and the Dawson anion. TG analysis displayed a relative thermal stability of the hybrid material compared to the parent Dawson POM. The new hybrid material [BMIM]6P2Mo18O62 was immobilized on glassy carbon (GC) electrode and the modified electrode was investigated by cyclic voltammetry and amperometry. Compared to the electrochemical behavior of dissolved [P2Mo18O62]6−, a slight shift in the redox peaks towards negative potentials is observed for the immobilized [BMIM]6P2Mo18O62. The relationship between the peak currents of the deposited [BMIM]6P2Mo18O62 film and scan rate is shown to be linear, which demonstrates a surface-confined electron transfer processes. [BMIM]6P2Mo18O62 modified electrode showed high sensitivities towards pH and shown to be active even at neutral pH. [BMIM]6P2Mo18O62 modified GC electrode was subjected to cyclic voltammetry and amperometry in the presence of ascorbic acid (AA) and found to exhibit a remarkable catalytic activity towards the oxidation of AA. The catalytic oxidation peak of AA at [BMIM]6P2Mo18O62 modified GC electrode occurs at low potential of ∼0 V vs Ag/AgCl at neutral pH and shifts to more positive potentials when pH decreases. Comparison between [BMIM]6P2Mo18O62 and [P2Mo18O62]6− modified GC films towards the oxidation of AA suggests that the significant decrease in the overpotentials recorded with [BMIM]6P2Mo18O62 film is related to the presence of ionic liquid cation in the hybrid material, which probably plays the role of the redox mediator. The resulting AA sensor [BMIM]6P2Mo18O62/GC has a significant sensitivity of ∼63 nA/μM AA, fast response time (<9 s), low detection limit (<0.1 μM), high selectivity towards endogenous interferences such as uric acid, acetaminophen and dopamine, a linear range from 0.1 μM to at least 22 mM AA and was stable for at least 2 weeks. In addition, such AA sensors can operate in a pH range from 0 to at least 7. 相似文献
19.
Mostafa Yousefi Maryam Ranjbar 《Journal of Inorganic and Organometallic Polymers and Materials》2017,27(3):633-640
In the present study nano-sized strontium-doped lanthanum manganite, La0.75Sr0.25MnO3 (LSM), were synthesized by three simple different methods (a) co-precipitation, (b) ultrasonic and (c) microwave-assisted co-precipitation. A lanthanum(III) coordination polymer, [pyda.H]2[La2(pydc)4(H2O)4]·2H2O, where [pyda.H]+?=?2,6-diaminopyridinium, and (pydc)2??=?2,6-pyridinedicarboxylate, was used as a new precursor. The products were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), field emission scanning electron microscope (FESEM), thermal gravimetric (TG) and differential thermal analyses (DTA), as well as by Energy-dispersive X-ray spectroscopy (EDX). The XRD results showed that the crystal lattice of the product obtained was orthorhombic perovskite structure. The porosity, particle size and homogeneity of calcinated LSM were strongly dependent on the preparation method. In addition, the results proved that the product formation time was decreased considerably when ultrasonic or microwave irradiation methods were used. 相似文献
20.
E. Laouini J. Douch M. Hamdani Y. Berghoute M. H. Mendonça M. I. S. Pereira R. N. Singh 《Journal of Applied Electrochemistry》2011,41(6):731-740
Spinel type CoFe2O4 thin films have been prepared, on stainless steel supports, by thermal decomposition of aqueous solutions of mixed cobalt
and iron nitrates in 1:2 molar ratio at 400 °C. The electrochemical behaviour of the CoFe2O4/1 M KOH interface was investigated by cyclic voltammetry, chronoamperometry and impedance techniques. The studies allowed
finding out the redox reactions occurring at the oxide surface. The results were compared with colloidal electrodes prepared
by alkaline precipitation of Fe(II) or Fe(III) hydrous oxi-hydroxides on platinum electrodes. In addition, it has been concluded
that the processes are diffusion-controlled and the diffusion of the hydroxide ion, through the oxide, acts as the rate-determining
step. The diffusion coefficient of OH− through the oxide film was determined using cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscopy
techniques. 相似文献