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1.
The effect of coumarin on the “deposition potential” of a number of metals at solid metal surfaces has been compared with that at a dropping mercury electrode. These results have been used to interpret the adsorption of coumarin on different metal surfaces and to suggest that Tl+ and Pb2+ ions are specifically adsorbed on mercury and that Tl+, Co2+, Fe2+, Ni2+ and Zn2+ are specifically adsorbed on their parent metals. 相似文献
2.
Mojtaba Shamsipur Mohammad Hossein Mashhadizadeh 《Separation and Purification Technology》2000,20(2-3):147-153
Hexathia-18-crown-6 (HT18C6) was used as a specific ion carrier for the transport of silver ion through a chloroform bulk liquid membrane. In the presence of thiosulfate ion as a suitable stripping agent in the receiving phase, the amount of silver transported across the liquid membrane after 60 min is 99.5±1.0%. The selectivity of Ag+ transport from the aqueous solutions containing other Mn+ cations such as Tl+, Mg2+, Ca2+, Mn2+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+, Pb2+, Hg2+, and Cr3+ ions was investigated. Except with Hg2+ ion, non of the cations used interfere the silver transport, even at a Mn+/Ag+ molar ratio of 500. The interfering effect of Hg2+ ion was successfully eliminated in the presence of EDTA at pH 5. 相似文献
3.
以虾壳酶解残渣为原料,经5%盐酸脱钙处理4 h后,用45%氢氧化钠和460 W微波辅助脱乙酰处理10 min,得到脱乙酰度为40.4%的改性甲壳素。将改性甲壳素加入海藻酸钠水溶液中混合均匀,挤压滴入氯化钙水溶液中固化12 h,制备得到直径为1.5~3.2 mm的凝胶小球,研究了该凝胶球对Pb2+、Cr3+、Ni2+、Cu2+、Co2+和Zn2+的吸附效果。结果表明:凝胶球对Cu2+、Co2+和Zn2+的吸附效果最好,300 mg/L重金属离子溶液吸附处理8 h是较适宜的吸附条件,此条件下,Cu2+、Co2+和Zn2+的吸附率分别达到94.2%、75.6%和57.3%。在Cu2+-Co2+-Zn2+共存溶液体系中,凝胶球对3种离子的吸附率均有所提高,Cu2+、Co2+和Zn2+的吸附率分别为95.1%、82.5%和67.5%。 相似文献
4.
The effect of transition metal ions(M~(2+)=Mn~(2+),Ni~(2+),Co~(2+),Cu~(2+)) on the chemical synthesis of polyaniline(PANI) used as a platinum-free counter electrode(CE) in dye-sensitized solar cells(DSSCs) was investigated.PANI was synthesized by co-polymerization of aniline in the presence of different transition metal ions by using potassium dichromate in acidic medium. It was found that the ion doping of PANI showed a certain catalytic activity for the regeneration of traditional iodide/triiodide(I~-/I_3~-) redox couples. The power conversion efficiency(η) of PANI CEs doped with Mn~(2+),Ni~(2+),Co~(2+) (4.41%, 2.36% and 2.10%, respectively) were higher than 1.94%, the value measured for PANI CE without doping. Doping with Cu~(2+)decreased the power conversion efficiency of PANI CE(PANI-Cu~(2+) η = 1.41%). The electrical properties of the PANI, PANI-Ni~(2+), PANI-Co~(2+),PANI-Mn~(2+) and PANI-Cu~(2+) were studied by cyclic voltammetry(CV), impedance(EIS), and Tafel polarization curve. The experimental results confirmed that PANI was affected by the doping of different transition metal ions(M~(2+)=Mn~(2+),Ni~(2+),Co~(2+),Cu~(2+)). These results indicate a potential application of ion doped PANI as counter electrode in cost-effective DSSCs. 相似文献
5.
Subramani Velu Kenzi Suzuki Munusamy Vijayaraj Sanmitra Barman Chinnakonda S. Gopinath 《Applied catalysis. B, Environmental》2005,55(4):287-299
A series of CuNiZnAl-multicomponent mixed metal oxide catalysts with various Cu/Ni ratios were prepared by the thermal decomposition of Cu1−xNixZnAl-hydrotalcite-like precursors and tested for oxidative steam reforming of bio-ethanol. Dehydrogenation of EtOH to CH3CHO is favored by Cu-rich catalyst. Introduction of Ni leads to CC bond rupture and producing CO, CO2 and CH4. H2 yield (selectivity) varied between 2.6–3.0 mol/mol of ethanol converted (50–55%) for all catalysts at 300 °C. The above catalysts were subjected to in situ XPS studies to understand the nature of active species involved in the catalytic reaction. Core level and valence band XPS as well as Auger electron spectroscopy revealed the existence of Cu2+, Ni2+ and Zn2+ ions on calcined materials. Upon in situ reduction at reactions temperatures, the Cu2+ was fully reduced to Cu0, while Ni2+ and Zn2+ were partially reduced to Ni0 and Zn0, respectively. On reduction, the nature of ZnO on Cu-rich catalyst changes from crystalline to amorphous, relatively inert and highly stabilized electronically. Relative concentration of the Ni0 and Zn0 increases upon reduction with decreasing Cu-content. Valence band results demonstrated that the overlap between 3d bands of Cu and Ni was marginal on calcined materials, and no overlap due to metallic clusters formation after reduction. Nonetheless, the density of states at Fermi level increases dramatically for Ni-rich catalysts and likely this influences the product selectivity. 相似文献
6.
Using a local density functional calculation, we investigate the adsorption energies, geometries and electronic structures of single Cu2+ and Fe2+ ions on a Si(100) surface. The adsorption energy results reveal that both ions are stably adsorbed in a hollow site; from this site, Cu2+ is located at 0.51 Å and Fe2+ is located at 0.41 Å from the surface, respectively. The adsorption energy of Cu2+ is about 1.5 times larger than that of Fe2+. This means that Cu2+ is strongly adsorbed on the silicon surface. From the analysis of spin density, we find that Cu2+strongly attracts the electrons of the silicon surface, because spin density is delocalized in the silicon backbone. As a result, the 3d orbital of Cu2+ becomes more similar to the closed-shell state compared to that of Fe 2+. This means that the core electronic state of Cu2+ is closer to the neutral atom, which is qualitatively confirmed by XPS measurements. 相似文献
7.
Fumiaki Amano Sosuke Suzuki Takashi Yamamoto Tsunehiro Tanaka 《Applied catalysis. B, Environmental》2006,64(3-4):282-289
The H2-TPR (temperature-programmed reduction) study was performed for supported copper oxide catalysts with low loading (0.5 wt% as copper). Among the various kinds of support materials (γ-Al2O3, TiO2, ZrO2, SiO2, ZSM-5), alumina-supported copper oxide indicated a one-electron reduction behavior of Cu2+ into Cu+ ions in the presence of H2. The reduction of the isolated Cu2+ species in a tetragonally distorted octahedral symmetry into the low coordinated Cu+ ions was identified by means of X-ray absorption spectroscopy (XANES and EXAFS). The isolated Cu+ ions hosted by γ-Al2O3 surface were prevented from further reduction into metallic Cu0 state under reducing condition with H2 at 773 K. Less dispersed supported copper oxide species were easily reduced to Cu0 metal particles with H2 at 573 K regardless of the kinds of support materials. It is suggested that the one-electron redox behavior of the isolated copper oxide species over γ-Al2O3 promotes the catalytic reduction of NO with CO in the presence of oxygen on the basis of redox-type mechanism between Cu2+ and Cu+ in atomically dispersed state. 相似文献
8.
Jiehui Zeng Jianxian Zeng Hu Zhou Guoqing Liu Zhengqiu Yuan Jian Jian 《Frontiers of Chemical Science and Engineering》2020,14(6):1018
An ion-imprinted sorbent (IIP) was prepared by using Ni2+ as template, 3-[2-(2-aminoethylamino) ethylamino] propyl-trimethoxysilane as functional monomer, and silica gel as carrier. The adsorption performance of IIP towards Ni2+ was investigated. IIP showed a higher adsorption capacity than that of non-imprinted sorbent, and it also exhibited high selectivity for Ni2+ in the presence of Cu2+ and Zn2+ ions. Then, IIP was used to form a dynamic membrane onto the surface of ceramic membrane for treatment of electroplating wastewater containing Ni2+. Compared with ceramic membrane, IIP dynamic membrane had much higher steady membrane flux, and also rejected Ni2+ to obtain a lower concentration of Ni2+ in the permeate fluid. Perhaps it is suitable for future practice applications. 相似文献
9.
Hydroxyapatite (Ca10(PO4)6(OH)2: HAP) was co-substituted with Ti(IV) and antibacterial ions (Ag+, Cu2+ or Zn2+) (HAPTiM), by coprecipitation and ion-exchange methods. Both HAPTiAg and HAPTiCu coated on porous spumous nickel film showed high efficiency for killing Escherichia coli and Staphylococcus aureus in the dark and under weak UVA irradiation, respectively. Moreover, their bactericidal activities were much higher than that of P25-TiO2 film. The studies of ESR revealed that not only O2− was formed on HAPTiM, HAPTi, HAP and P25-TiO2 films under weak UVA irradiation, but also at ambient temperature without light O2− was generated on HAPTiCu, HAPTiAg, and HAPTi. The redox couples of Cu0/Cu2+ and Ag0/Ag+ in the structure of HAPTiCu (Ag) caused the transfer of electron leading to the O2− generation under the above conditions. The higher bactericidal activities of HAPTiM were due to the synergy of the oxidation role of the O2− and the bacteriostatic action of antibacterial ions. The process of the damage of the cell wall and the cell membrane was directly observed by TEM, and further confirmed by the determination of potassium ion (K+) leakage from the killed bacteria. 相似文献
10.
将转炉钢渣磨碎筛分,从钢渣投加量、吸附时间、酸性条件等方面探究其对水溶液中Ni2+的吸附性能及吸附机理,并讨论Cu2+对钢渣吸附Ni2+的影响。研究结果表明,100 mL浓度为50 mg·L-1的Ni2+溶液,用200目(0.074 mm)0.15 g的钢渣处理30 min,Ni2+的吸附率为99.88%。钢渣吸附Ni2+的过程符合准二级动力学模型和Freundlich等温模型。钢渣吸附Cu2+与吸附Ni2+属于竞争吸附,且钢渣对Cu2+的吸附能力优于对Ni2+的吸附能力。钢渣吸附Ni2+的过程以化学吸附为主,伴随着物理吸附,且随着钢渣表层吸附位点的减少,钢渣对Ni2+的物理吸附作用会逐渐减弱。该研究对处理工业含Ni2+与Cu2+的废水具有一定的指导意义。 相似文献
11.
Piotr Pietrzyk Filip Zasada Witold Piskorz Andrzej Kotarba Zbigniew Sojka 《Catalysis Today》2007,119(1-4):219-227
Molecular DFT modeling combined with computational spectroscopy (EPR and IR) were applied for analysis of the NO bond breaking and NN and OO bond making in the context of deNOx and deN2O reactions. Interaction of NO, N2O and NO2 with cationic (transition metals) and anionic (surface O2− ions) centers was explored at the molecular level. The elementary events such as reactant coordination, charge and spin redistributions, which are principal molecular constraints for efficient decomposition of the nitrogen oxides (N2O and NO) were discussed. Particular attention was paid to dynamics of the NO bond cleavage in N2O molecule through electron and oxygen atom transfer routes, evaluation of preferable coordination modes of NO, discrimination between inner- and outer-sphere mechanism of NN bond formation, and the influence of spin and electronic redistribution on the reaction course (spin catalysis). Owing to their simplicity and well known surface chemistry, model systems selected for studies of such processes include MoOx/SiO2, MgO and ZSM-5 zeolite exchanged with various transition metal ions (TMI) of different electron configuration and spin multiplicity: Mo5+ (d1, 2D) Fe3+, Mn2+, Cr+ (d5, 6S), Fe2+ (d6, 5D), Co2+ (d7, 4F), Ni2+ (d8, 3F), Cu2+ (d9, 2D) and Cu+, Zn2+ (d10, 1S). 相似文献
12.
目前,开发绿色高效的重金属吸附材料受到人们的广泛关注。以硅藻土为原料,经水热法选择性地制备了2类硅酸盐材料即麦羟基硅钠石和方沸石。吸附测试结果表明,麦羟基硅钠石层间的钠离子能够与锂离子、镁离子、锌离子、钴离子、镍离子、铜离子等进行阳离子交换且能保持层状母体框架的稳定性。以钴离子、镍离子为例深入研究其吸附动力学和吸附机制发现,钴离子和镍离子的嵌入分别将麦羟基硅钠石的层间距由本征的1.56 nm减小到0.24、0.23 nm;室温下,对钴离子、镍离子的最大吸附量分别可达45、39 mg/g,均符合Langmuir单层吸附模型;钠离子的置换量大约是吸附的钴离子、镍离子量的两倍,证实层间离子交换主导吸附化学过程。因此,麦羟基硅钠石材料在多金属硅酸盐功能材料的合成以及环境吸附净化领域具有较大的应用潜力。 相似文献
13.
采用二次合成法合成ZSM-5分子筛膜,并用XRD和SEM对其表面进行表征,所合成的膜为ZSM-5分子筛膜。对分子筛膜用Ag+、Cu2+、Fe3+金属离子进行改性,改变离子浓度,然后应用于模拟汽油中苯并噻吩和2,5-二甲基噻吩的分离性能研究,同时还考察了不同料液温度、再生次数对膜脱硫的影响。实验结果表明:负载Ag+浓度为0.2 mol/L时对苯并噻吩和2,5-二甲基噻吩的分离效果最好,分离因子最高可达到1.65;料液温度在常温(25 ℃ )下脱硫效果最好,通过简单方法对膜进行再生,考察再生膜脱硫具有较好的稳定性。 相似文献
14.
The mechanism of plating on anodized aluminum was investigated. Porous anodic films were formed on 1100 aluminum and the electrochemical behaviour of a number of test reactions (Ag+/Ag, Cu2+/Cu, [Fe(CN)6]4− /[Fe(CN)6]3− and QH2/Q) was determined. Hydrogen evolution can damage the oxide film and enhance the rate of electrochemical reactions on the surface. It is not a prerequisite, however, for metal deposition and other electrode reactions. Under the experimental conditions studied, the activity of the pores was not uniform and metal was plated in only a fraction of the pores, even when the total charge passed exceeded that required to fill all the pores tenfold or more. Metal ions can penetrate the barrier layer at the bottom of the pores by migration or diffusion, to be discharged at the aluminum surface. The barrier layer may also act as a heavily doped semiconductor which allows passage of charges with no specificity for the reversible potential of the redox couple tested. Observation of the uniformity of deposition of metals into the pores at an early stage by SEM with electron microanalysis can serve as a powerful tool in determining the best conditions for uniformly filling the pores. This should lead to improvements in the quality of plating on anodized aluminum. 相似文献
15.
The electronic states of LaMn1−xCuxO3+λ (x=0–0.4) have been studied with X-ray photoelectron spectroscopy (XPS). The valence states of substituted copper ions were Cu2+ and the manganese ions were a highly mixed state of Mn3+ and Mn4+. The nonstoichiometry and electronic state of lattice oxygen have been studied. The samples at x=0 and 0.1 had an excess of lattice oxygen but those at x=0.2–0.4 had lattice oxygen deficiency. A modified Auger parameter (Δ′) was used to evaluate the electronic states of oxygen ions. The Δ′ of lattice oxygen increased with increasing substitute quantity. This increase of Δ′ reflected the decrease of ionic bond character of lattice oxygen. The adsorbed oxygen species on LaMn1−xCuxO3+λ was assigned mainly as O− from the peak positions of spectra for the O 1s and O KLL levels, and the Δ′ of this O− decreased with x. This decrease, i.e., the increase of ionic bond character of adsorbed oxygen was correlated well with the value of nonstoichiometry of lattice oxygen.
The rate of CO oxidation at 448 K was increased by the substitution till x=0.4. We consider that this enhancement of reactivity comes from the change of electronic state of adsorbed oxygen, O− itself, i.e., a weak interaction between O− and low coordinated metal site brings about a high reactivity. 相似文献
16.
The inhibition effect of Ag+ ions on the photoanodic corrosion of CdS semiconductor electrodes has been studied in 0.5 M NaClO4 + xM AgClO4 solutions (0 x 10−2, pH = 2) by means of potentiostatic current density-potential measurements, ac-impedance and atomic absorption. In the presence of Ag+ ions in the solution a thin Ag2S film of ca. 30–300 nm thickness is formed on the CdS surface due to the heterogeneous cation exchange reaction CdS + 2Ag+ = Ag2S + Cd2+. The Ag2S film formation is a transport controlled process which can be described by a parabolic rate law. From kinetic investigations in the temperature range (298 T 348 K) the activation energy of this process was determined to be about 62 kJ mol−1. Information about the morphology and composition of the surfaces was obtained from optical and scanning electron microscope investigations including EDAX. 相似文献
17.
Characterization and NO decomposition activity of Cu-MFI zeolite in relation to redox behavior 总被引:1,自引:0,他引:1
Y. Teraoka C. Tai H. Ogawa H. Furukawa S. Kagawa 《Applied Catalysis A: General》2000,200(1-2):167-176
The redox behavior and states of Cu ions in Cu ion-exchanged MFI (Cu(n)-MFI, n: exchange level) have been investigated by means of temperature-programmed desorption (TPD) of oxygen, diffuse reflectance (DR) UV–VIS spectroscopy and Cu+ photoluminescence (PL) spectroscopy. TPD chromatograms of oxygen from Cu(n)-MFI were characterized by the appearance of three desorption peaks: (below 200°C), β (300–500°C) and γ (above 500°C). It has been suggested that and β oxygen are extra-lattice oxygen adsorbed on Cu ions, while γ oxygen is lattice oxygen coordinated to Cu ions. The Cu+ emission was tremendously reduced once the catalyst contacted with O2 and NO at elevated temperatures such as 500°C, and it was almost invisible under the working state of the catalyst, suggesting that PL-active Cu+ ions are not real active sites under the working state. The desorption of β oxygen was intimately related to the creation of active centers for the NO decomposition reaction. DR measurements showed that the desorption of β oxygen caused tetragonal Cu2+ to decrease and trigonal Cu2+ to increase simultaneously. It has been proposed that both Cu2+ and Cu+ are involved in the NO decomposition catalysis over Cu-MFI under the working state. 相似文献
18.
Protein-derived nitrogen and sulfur co-doped carbon for efficient adsorptive removal of heavy metals
A nitrogen and sulfur co-doped carbon has been synthesized employing egg white as a sustainable protein-rich precursor. According to CHNS elemental analysis, N, S and O heteroatoms accounted for mass fractions of 3.66%, 2.28% and 19.29% respectively, and the types of surface functionalities were further characterized by FT-IR and XPS measurements. Although the carbon possessed a smaller surface area (815 m2·g-1) compared to a commercial activated carbon (1100 m2·g-1), its adsorption capacity towards Co2+ reached 320.3 mg·g-1, which was over 8 times higher compared to the limited 34.0 mg·g-1 over the activate carbon. Furthermore, the carbon was found to be an efficient adsorbent towards a series of metal ions including VO2+, Cr3+, Ni2+, Cu2+ and Cd2+. Combined with its environmental merits, the protein derived carbon may be a promising candidate for heavy metal pollution control. 相似文献
19.
《Catalysis Today》1988,3(5):401-406
On a series of Ni---Y stabilized zeolite samples, differing in method of Ni2+ ions incorporation, Si/Al ratio and acidity of OH groups, the influence of the zeolitic matrix on the reducibility of Ni2+ ions was studied using temperature programmed reduction (TPR), i.r. and adsorption. The stabilized structure enables the reduction of Ni2+ ions even at an ion exchange degree of 6 Ni2+ per unit cell. The Ni2+ ions incorporated by impregnation of the zeolite with Ni-ammocomplex exhibit higher reducibility than those incorporated by ion exchange. On the partially dealuminated samples, the reducibility of Ni2+ is proportional to the Si/Al ratio. The reducibility of Ni2+ ions is suppressed by the presence of acidic structural OH groups in zeolite. 相似文献
20.
Complete Ni2+ exchange of a single crystal of zeolite X of composition Na92Si100Al92O384 per unit cell was attempted at 73°C with flowing aqueous 0.05 M NiCl2 (pH=4.3 at 23°C). After partial dehydration at 23°C and ≈10−3 Torr for two days, its structure, now of composition Ni2(NiOH)35(Ni4AlO4)2(H3O)46Si101Al91O384 per unit cell, was determined by X-ray diffraction techniques at 23°C (space group Fd
, a0=24.788(5) Å). It was refined using all intensities; R1=0.080 for the 236 reflections for which Fo>4σ(Fo), and wR2=0.187 using all 1138 unique reflections measured. At four crystallographic sites, 45 Ni2+ ions were found per unit cell. Thirty of these are at two different site III′ positions. Twenty of those are close to the sides of 12-rings near O–Si–O sequences, where each coordinates octahedrally to two framework oxygens, to three water molecules which hydrogen bond to the zeolite framework, and to an OH− ion. The remaining 10 are near O–Al–O sequences; only three members of a likely octahedral coordination sphere could be found. In addition, two Ni2+ ions are at site I, eight are at site I′, and five are at site II. Forty six H3O+ ions per unit cell, 24 at site II′ and 22 at site II, each hydrogen bond triply to six rings of the zeolite framework. Each of the 22 H3O+ ions also hydrogen bonds to a H2O molecule that coordinates to a site III′ Ni2+ ion. Six of the eight sodalite cages each contain four H3O+ ions at site II′; the remaining two each contains a tetrahedral orthoaluminate anion at its center. Each tetrahedral face of each orthoaluminate ion is centered by a site I′ Ni2+ ion to give two Ni4AlO4 clusters. The five site II Ni2+ ions each coordinate to a OH− ion. With 46 H3O+ ions per unit cell, the great tendency of hydrated Ni2+ to hydrolyze within zeolite X is demonstrated. With a relatively weak single-crystal diffraction pattern, with dealumination of the zeolite framework, and with an apparent decrease in long-range Si/Al ordering likely due to the formation of antidomains, this crystal like others treated with hydrolyzing cations appears to have been damaged by Ni2+ exchange and partial dehydration. 相似文献