Y型分子筛的红外光谱

研究了ＣｏＮａＹ, ＮｉＮａＹ, ＣｄＮａＹ,ＣａＮａＹ 及晶体结构已被破坏的“ＣｒＮａＹ”, 在５２３ Ｋ 和１０ － １Ｐａ条件下处理后及其吸附苯后的红外光谱, 认为４１５ｃｍ － １ 谱带归属于六元环的振动, ４０３ｃｍ － １ 归属于十二元环的振动, ５１１ｃｍ － １ 吸收谱带归属于 Ｏ１Ｓｉ Ｔ 的弯曲振动。解释了Ｙ 型分子筛的 Ｏ１Ｓｉ Ｔ 易于断裂及５１１ｃｍ － １ 谱带频率大于４６２ｃｍ － １ 谱带频率的原因。     

不同阳离子Y型分子筛的红外研究

研究了CrNaY(晶体结构已经破坏 )及CoNaY ,NiNaY ,CNaY和CaNaY的红外光谱 ,认为 :115 0～10 5 0cm-1和 85 0～ 75 0cm-1分别归属于Si—O—T的反对称和对称伸缩振动 ,同时发现 :CoNaY ,NiNaY ,CdNaY和CaNaY在真空加热处理后 ,CoNaY和NiNaY在 95 0～ 85 0cm-1范围内出现吸收峰。     

Microwave-assisted synthesis of L-cysteine-capped nickel nanoparticles for catalytic reduction of 4-nitrophenol

A simple and efficient microwave-assisted procedure for synthesis of L-cysteine-capped nickel nanoparticles(cyst-Ni NPs) in ethylene glycol solvent was demonstrated. The as-synthesised NPs were characterised by ultraviolet–visible(UV–Vis) spectrophotometer, Fourier transform infrared(FTIR) spectroscopy, transmission electron microscopy(TEM) and X-ray diffractometry(XRD). The cyst-Ni NPs are proved to be excellent heterogeneous catalysts for the 100% reduction of 4-nitrophenol(4-NPh) in the presence of reductant(Na BH4)within reaction time of 40 s. In contrast, Raney nickel in similar sample environments shows only 25.5% reduction.The kinetic and energetic behaviours of cyst-Ni NPs were also studied, and the reduction reaction is determined to follow pseudo-first-order kinetics with a rate constant value of 0.115 s-1 and activation energy of 36.1 kJ·mol-1. In addition to its high catalytic competence, cyst-Ni NPs catalyst exhibits excellent recyclability with negligible catalytic poisoning.     

Thermodynamics of methane adsorption on X type zeolites at supercritical temperatures

Methods describing isotherms and thermodynamic properties of methane adsorption on various cationic forms of X-type zeolite at temperatures above critical ones are considered.     

嗜酸氧化亚铁硫杆菌在黄铜矿表面的短期吸附实验研究(英文)

为了探明细菌在黄铜矿表面的吸附机制,采取短期吸附的实验方法,研究吸附时间、矿浆浓度、细菌浓度、pH值和离子强度等因素对吸附行为的影响。结果表明,细菌吸附量随初始细菌浓度和矿浆浓度的增加而增大。Acidithiobacillus ferrooxidans在黄铜矿表面的最佳吸附pH范围为1-3。离子强度的增大会抑制细菌吸附,这一现象可以通过双电层理论得到很好的解释。细菌与黄铜矿的吸附行为受疏水性和静电作用力共同影响。     

Silver nanoparticle catalyst for electroless Ni deposition and the promotion of its adsorption onto PET substrate

Silver nanoparticle catalyst was prepared to replace Pd catalyst for electroless Ni plating. The adsorption of Ag nanoparticle onto the poly(ethylene terephthalate) (PET) was promoted by conditioning the substrate with 3-aminopropyltrimethoxysilane and 3-mercaptopropyl- triethoxysilane. Electroless Ni deposition was started at the PET substrates catalyzed with Ag nanoparticle linking to the substrate via Ag-S bond. The composition and topography of nickel plating PET films were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and energy dispersive X-ray (EDX) analysis, respectively. Peel adhesion strength, more than 50 N/cm, was achieved for planting nickel layer to the Ag activated PET substrate; however, a relative low value as 10.2 N/cm was obtained for the sample with Pd catalyst by the same measurement. Silver catalyst together with silane modification has the significant merits for electroless deposition of Ni on PET film.     

Thermodynamics and kinetics of adsorption for heavy metal ions from aqueous solutions onto surface amino-bacterial cellulose

Amino-bacterial cellulose (amino-BC) was prepared by chemical modification of bacterial cellulose(BC). The adsorption characteristics and mechanism of amino-BC were studied. The results show that adsorption data can be fitted well by Langmuir equation and the pseudo-second order kinetics, indicating that the adsorption of amino-BC would obey monolayer molecule adsorption and the main action was chemisorption. Meanwhile, the adsorption process was studied by the Elovich equation and the intra-particle diffusion model, indicating that the absorption characteristics of metal ions on amino-BC is controlled by both film diffusion and particle diffusion. The increase of reaction temperature will accelerate the adsorbing rate because of endothermic reaction.     

Equilibrium and kinetic data of adsorption and separation for zirconium and hafnium onto MIBK extraction resin

The equilibrium and kinetics of methyl isobutyl ketone (MIBK) extraction resin for adsorption and separation of zirconium and hafnium were studied under the different conditions of acidity, initial total concentrations of zirconium and hafnium and temperature. The equilibrium data of both zirconium and hafnium are found to follow the Freundlich adsorption isotherm, and the Freundlich isotherm constants (K_F) are 3.53 and 0.64 mg/g, respectively. The equilibrium data of zirconium also fit the Langmuir adsorption isotherm, and the saturation adsorption capacity (Q_max) and the Langmuir isotherm constant (K_L) are 75.93 mg/g and ?0.012 7 L/g, respectively. The obtained kinetic data of both zirconium and hafnium are found to fit the HO pseudo-second-order kinetic model, and the rate constants of pseudo-second-order equation (k₂) are ?0.019 and 0.41 g/(mg·min), respectively. Column tests show that the MIBK extraction resin could be used as efficient adsorbent material for separating hafnium from zirconium.     

A method for investigation of hot corrosion by gaseous Na2SO4

A novel in situ exposure method for investigating hot corrosion of aluminde coatings in the absence of an alkali sulphate melt is presented. The samples are exposed to Na₂SO₄(g) at a temperature above the dew point of the gas. Results from 100 and 500 h exposures at 900 °C of Ni-based In792 covered with SIF232 aluminide coating are presented. Already after 100 h of testing, attack characteristic for Type I hot corrosion is observed. The reactions taking place during the testing are discussed and the results are compared with those from the well-known ex situ salt hot corrosion test.     

Calculations of the similarity factor and initial adsorption heats of substances on LiX,NaX, and KX zeolites

Based on an electrostatic model, the energies interaction between substances with different electron structures on one hand, and the LiX, NaX, and KX zeolites, on the other hand, as well as the similarity factors of characteristic adsorption curves of substances, are calculated.     

In situ spectroscopic investigation of the anodic oxidation of 1,4-dimethoxybenzene at platinum electrodes

The electrooxidation of p-dimethoxybenzene on platinum electrodes in strictly dried acetonitrile solutions was studied by in situ spectroscopic methods (UV–Vis differential reflectance, FT-IR reflectance and electron spin resonance (ESR) spectroscopies). The UV–Vis and IR spectra allowed us to investigate the early stages of polymerization and to monitor the film growth, as a function of the electrode potential and the number of potential cycles. The use of both p- and s-polarized IR radiations allowed us to observe the initial step of formation of the radical-cation and its dimerization at the electrode surface or its diffusion in solution. These observations were corroborated by ESR spectroscopy, which showed clearly the participation of the monomer and oligomer radicals in the electropolymerization process. On the other hand, the monomer concentration is a very important factor for molecular orientation at the electrode surface and formation of the polymer film.     

Modification of Langmuir isotherm for the adsorption of asphaltene or resin onto calcite mineral surface: Comparison of linear and non-linear methods

In this paper, the Langmuir isotherm, originally derived for the adsorption of three samples of asphaltenes and one sample of resin onto calcite, was modified to fit the adsorption isotherm. The modified Langmuir isotherm parameters obtained from the four linear equations using the different linear method. The aim of this modification is based on the fact that direct application of the Langmuir isotherm often leads to poor data fitting. In the present communication, it is shown that the level of data fitting to the Langmuir isotherm can be improved by a simple modification introducing a concentration dependent factor, X. Four Modified Langmuir linearized isotherm models and one non-linear isotherm model was discussed in this paper, and their coefficients were estimated. In the present study, to study non-linear isotherm model, genetic algorithm was used. A genetic algorithm procedure was utilized to optimize the modified Langmuir constants for a more accurate estimation of the set of model parameters. The obtained results demonstrate that the best fit is obtained using genetic algorithm. Furthermore, it is found that among the mentioned different samples of oil, filtered shale oil follows a multilayer adsorption isotherm.     

Deposition of Pd on Co(OH)2 nanoplates in stabilizer-free aqueous phase for catalytic reduction of 4-nitrophenol

Palladium-supported cobalt hydroxide (Co(OH)₂-Pd) nanoplates were fabricated in an aqueous solution and employed as a catalyst for the reduction of 4-nitrophenol. For the preparation of Co(OH)₂-Pd, Pd nanoparticles were anchored on the Co(OH)₂ nanoplates after the reduction of Na₂PdCl₄ by ascorbic acid in the absence of a stabilizer at room temperature. The observations under transmission and scanning electron microscopy reveal that Pd nanoparticles with a size of 2–5 nm are uniformly dispersed on the surface of the Co(OH)₂ nanoplates. In catalytic test, the conversion of 4-nitrophenol to 4-aminophenol is completed within 6 min in the presence of Co(OH)₂-Pd(1000) nanoplates with 2.18 at.% Pd, and the corresponding kinetic constant is 0.0089 s^-1 in the first test. The catalyst retains relatively high activity after several cycles. The results demonstrate that the Co(OH)₂-Pd(1000) nanoplates exhibit high catalytic activity toward the reduction of 4-nitrophenol in the presence of NaBH₄.     

Electrochemical and thermodynamic investigation of diniconazole and triadimefon as corrosion inhibitors for copper in synthetic seawater

This paper presents the investigation of diniconzole and triadimefon as chemical corrosion inhibitors for freshly polished copper in synthetic seawater (3.5% NaCl solution). Determination of weight loss, polarization curves, electrochemical impedance spectroscopy (EIS), and SEM, were performed to analyze the inhibiting performance of these compounds. Polarization curves show that they act as mixed-type inhibitors. EIS indicates that an adsorption film of the inhibitors is formed on copper surface. The highest values of inhibition efficiency are respectively, 99.2% and 97.3% at 100 mg/L concentration. Thermodynamic calculation suggests that chemisorptions between the compounds and copper are accordance with Langmuir adsorption isotherm.     

Micromagnetic and Mössbauer spectroscopic investigation of strain-induced martensite in austenitic stainless steel

Strain-induced martensite in 18/8 austenitic stainless steel was studied. Magnetic measurements and Mössbauer spectroscopic investigations were performed to characterize the amount of α’-martensite due to room-temperature plastic tensile loading. The effects of cold work and annealing heat treatment were explored using magnetic Barkhausen noise, saturation polarization, coercive force, hardness, and conversion electron Mössbauer spectra measurements. The results of the magnetic measurements were compared to results obtained by Mössbauer spectroscopy. The suggested Barkhausen noise measurement technique proved to be a useful quantitative and nondestructive method for determining the ferromagnetic phase ratio of the studied alloy.     

Comparative study of linearized and non-linearized modified Langmuir isotherm models on adsorption of asphaltene onto mineral surfaces

In this paper, the Langmuir isotherm, originally derived for the adsorption of asphaltene extracted from shale oil and dissolved in toluene on Kaolin, Smectite, Fluorite and Hematite, was modified to fit the adsorption isotherm. The modified Langmuir isotherm parameters obtained from the four linear equations using the linear method differed. The aim of the proposed modification is based on the fact that direct application of the Langmuir isotherm often leads to poor data fitting. In the present communication, it is shown that the level of data fitting to the Langmuir isotherm can be improved by a simple modification through introducing a concentration dependent factor, X. The present paper discusses four modified Langmuir linearized isotherm models and one non-linear isotherm model: their coefficients are estimated and, for the study of non-linear isotherm model, genetic algorithm is used. A genetic algorithm procedure was utilized to optimize the modified Langmuir constants for a more accurate estimation of the set of model parameters. The obtained results demonstrated that the best fit was obtained using genetic algorithm. Furthermore, it was found out that from the surface minerals mentioned, Hematite mineral follows a multilayer adsorption isotherm.     

A laser spectroscopic study of Nd-doped zirconia

High-surface-area rare-earth (RE) modified zirconia powders prepared by solution methods can be used as catalytic support of noble metals and as electrolyte oxygen sensors in an automobile exhaust-emission-control system. A previous neutron-scattering study showed that substituting zirconium with trivalent RE ions not only stabilizes the cubic and tetragonal phases over a wide range of temperatures, but also creates oxygen vacancies in the RE–Zr oxide solid solution. This work focuses on the fluorescence of Nd in Nd_0.1Zr_0.9O_1.95 powders under laser excitation of the Nd³⁺ ground state to the ⁴G_7/2 states. Distinct features were observed at 8 K in the ⁴I_9/2→⁴G_7/2 excitation and ⁴F_3/2→⁴I_9/2 emission spectra using two sets of incident and emission frequencies, respectively. The results are discussed in terms of site-sensitive local structures surrounding the Nd ions in the two-phased oxide structure.     

Electric discharge treatment of zeolites for purifying the waste water of polymer-manufacturing plants

We present the results of electric discharge treatment of zeolites for purifying the waste water from the manufacture of polymers. By application of the thermostimulated relaxation method, it has been revealed that in the zeolites, superficial and volumetric charges accumulate. It is shown that the electric discharge effects considerably enhance the efficiency of the adsorptive purification of waste water.