SELECTIVE TRANSPORT OF GOLD(Ⅲ) THROUGH THE LIQUID MEMBRANE CONTAINING POLYTHIOETHER OLIGOMER AS CARRIER

This paper deals with the transport properties of oligomer of polythioether PSA used as mobile carrier in bulk liquid membrane for gold(Ⅲ). It was found that Au(Ⅲ) can be transported by PSA from source phase to receiving phase completely under appropriate conditions and only Au (Ⅲ) can be transferred through the liquid membrane to receiving phase from a mixture of Na(Ⅰ)-Cu(Ⅱ)-Au (Ⅲ) - Fe (Ⅲ) - Pt(Ⅳ) in the following system, HAuCl4 - HCl (aq.)/PSA -ClCH2-CH2Cl/(NH2)2CS-HCl(aq.). The transport rate of Au(Ⅲ) depended on the concentration of carrier, the thickness of liquid membrane, the concentration of Au(Ⅲ) in source phase and the acidity of the media.     

SELECTIVE TRANSPORT OF GOLD（Ⅱ） THROUGH THE LIQUID MEMBRANE CONTAINING POLYTHIOETHER OLIGOMER AS CARRIER

This paper deals with the transport properties of oligomer of polythioether PSA used as moble carrier in bulk liquid membrane for gold(Ⅲ).It was found that Au(Ⅲ) can be transported by PSA from source phase to receiving phase completely under appropriate conditions and only Au(Ⅲ) can be transferred through the liquid membrane to receiving phase from a mixture of Na(I)-Cu(Ⅱ）-Au(Ⅲ）-Fe(Ⅲ）-Pt(Ⅳ） in the following system:HAuCl4-HCl(aq.)/PSA-ClCH2-CH2Cl/(NH2)2CS-HCl(aq.).The transport rate of Au(Ⅲ） depended on the concentration of carrier,the thickness of liquid membrane,the concentration of Au(Ⅲ） in source phase and the acidity of the media.     

Extraction of cobalt(Ⅱ) from aqueous solution by N,N'-carbonyl difatty amides

The development of economic and environmentally friendly extractants to recover cobalt metal is required due to the increasing demand for this metal.In this study,solvent extraction of Co(Ⅱ) from aqueous solution using a mixture of N,N’-carbonyl difatty amides(CDFAs) synthesised from palm oil as the extractant was carried out.The effects of various parameters such as acid,contact time,extractant concentration,metal ion concentration and stripping agent and the separation of Co(Ⅱ) from other metal ions such as Fe(Ⅱ),Ni(Ⅱ),Zn(Ⅲ) and Cd(Ⅱ) were investigated.It was found that the extraction of Co(Ⅱ) into the organic phase involved the formation of 1:1 complexes.Co(Ⅱ) was successfully separated from commonly associated metal ions such as Fe(Ⅱ),Ni(Ⅱ),Zn(Ⅲ) and Cd(Ⅱ).Co(Ⅱ) stripping from the loaded organic phase was studied in aqueous solution.These results are useful to recover Co(Ⅱ) from aqueous solution utilising(CDFAs) as an extractant.     

BaxCe0.8Y0.2O3-α固体电解质的氧离子导电性

Ba_xCe_0.8Y_0.2O_3-α(x=1.03，1，0.98) solid electrolyte samples show a single phase of orthorhombic perovskite of BaCeO₃. The oxide-ion conduction and transport number were detected in the temperature of 600～1000℃ by electrochemical oxygen permeation (oxygen pumping)， and compared with the results from the oxygen concentration cell. The relation between the ingredient of Ba and oxide-ion conduction was also researched. It was found that these electrolytes exhibited the mixed oxide-ionic and electronic hole conduction under the experimental temperature and oxygen gas. The oxide-ion transport numbers are 0.1～0.6， which are close to the results of the oxygen con-centration cell. They increase as the decrease of Ba content in the samples.     

石英晶体微天平技术研究纳米TiO2表面Cu(Ⅱ)吸附与光化学还原过程

The adsorption and photochemical reduction process of Cu(Ⅱ) at the surface of nanocrystalline TiO₂ was investigated using in situ quartz crystal microbalance(QCM). It was found that the adsorption of Cu(Ⅱ) onto active sites of nanocrystalline fit the pseudo-second-order reaction better than the pseudo-first-order reaction, and that the rate constant of the reaction was estimated to be about 0.09 g·mmol₂·min₂. In addition, it was also found that the adsorption amount of Cu(Ⅱ) at the surface of TiO₂ was affected by pH、concentration and coexisting anions, and the saturated amount of adsorbed Cu(Ⅱ) was approximately 1.5 mmol·g^-1 at pH 4. During UV illumination, the frequency of QCM decreased gradually, which meant the photoreduction deposition of Cu(Ⅱ) from the solution, moreover, the rate of photodeposition of Cu(Ⅱ) increased with increasing pH of solution, and the rate of photoreduction enhanced obviously when the organics were introduced.     

TiO2胶粒在铝合金表面的电泳沉积及所制薄膜的光催化性能研究

TiO₂ membranes were prepared on aluminum-alloy thin plates by electrophoretic deposition and dip coating in a colloid solution of TiO₂, respectively. The photocatalytic activity of TiO₂ membrane was compared using ethylene as reactant, and the crystal and morphological structure of the membrane were characterized by XRD and SEM. The results showed that a more compact membrane with high loading of TiO₂ but lower photocatalytic activity of unit TiO₂ mass was obtained by electrophoresis compared with dip coating method. The addition of polyethylene glycol (PEG) to the sol of TiO₂ could improve the specific photocatalytic activity (ethylene conversion per unit mass TiO₂ and unit area of membrane piece) of the electrophoresis-membrane prepared from the sol, but could not change the specific photocatalytic activity of the dip-coating membrane from the sol. The ethylene conversion on the electrophoresis membrane prepared from the sol containing PEG (50 g·L^-1) was 9 times of that on the dip coating membrane. The effect of PEG on the properties of electrophoresis-membrane of TiO₂ was attributed to the change of electrokinetic properties of sol. Addition of PEG decreased ζ potential value of the sol and the mobility of the sol particle, increased viscidity of the colloid, thus decreasing both the electrophoresis deposition velocity of colloid particles and the electroosmosis velocity of diffuse layer of colloid particles. These favored the formation of a low compact and porous membrane on the electrode in electric field, and thus increasing the availability of TiO₂ in photocatalytic process.     

Competitive bulk liquid membrane transport of Co(Ⅱ),Ni(Ⅱ),Zn(Ⅱ),Cd(Ⅱ),Ag(Ⅰ),Cu(Ⅱ)and Mn(Ⅱ),cations using 2,2'-dithio(bis)benzothiazole as carrier

A series of competitive metal-ion transport experiments has been performed.Each involved transport from an aqueous source phase across an organic membrane phase into an aqueous receiving phase.The source phase contained equimolar concentration of Co（Ⅱ）,Ni（Ⅱ）,Zn（Ⅱ）,Cd（Ⅱ）,Ag（Ⅰ）,Cu（Ⅱ） and Mn（Ⅱ） metal cations.The transport experiments of metal cations were carried out by 2,2’-dithio（bis）benzothiazole（DTB） in chloroform（CHCl₃）.The source phase being buffered at range pH of 4-6.5 and receiving phase being buffered at pH 3.The obtained results show that the selectivity and the efficiency of Ag（I） transport from aqueous solutions are observed in this investigation.The effect of concentration of palmitic acid in the transport efficiency of Ag（Ⅰ） ion was also conformed.     

叠氮化钠与烟草多酚氧化酶相互作用的光谱学研究

N₃^- is a kind of ligand with very strong power for coordination, and is able to bind with many kinds of metal ions or metalloproteins. The metal ions in metalloproteins usually locate at the active site of them, and the combination of other chemical compound(s) to them will cause great influence on the structure and function of them. In addition, the combination can also provide information of the structure of the active site of the enzymes, and that of the higher-order structure of the enzyme. In this paper, we studied the interaction between N₃^- and PPOⅡ from Nicotina Tobacco by the determination of changes in enzymatic activity, UV-Vis, fluorescence spectra and FT-IR. The results showed that N₃^- can activate PPOⅡ with a near linear increase in enzymatic activity to the concentration of N₃^- when the [N₃^-]/[PPOⅡ](molar/molar) is less than or equal to 1.0, and that the enzymatic activity begins to decrease from 1.0 to 4.0; N₃^- didn’t coordinate directly with Cu²⁺ in the active site, but may interact with the side chain groups with positive charges, and further resulted in the increase in α-helix and the slightly decrease in β-turn, random coil and extended chain; the Cu²⁺ may locate deeply in the inner part of PPOⅡ, and coordinates strongly with nitrogen atoms in imidazole of histidine; N₃^- can quench the fluorescence of PPOⅡ, and make the microenvironments of Trp residues more polar after the interaction between N₃^- PPOⅡ.     

Study on supported combined liquid membrane containing HEH（EH）P and HNO3 for trivalent gadolinium transfer

A novel kind of supported combined liquid membrane（SCLM） has been studied for the Gd（Ⅲ） transfer.SCLM contained polyvinylidene fluoride membrane（PVDF） as the liquid membrane support and renewal solution including HNO₃ solution as the stripping solution and 2-ethyl hexyl phosphonic acid-mono-2-ethyl hexyl ester（HEH（EH）P） as the carrier dissolved in kerosene. The mixed solution of carrier and kerosene was membrane solution.The optimum transport conditions of Gd（Ⅲ） were that concentration of HNO₃ solution was 4.00 mol/L,concentration of carrier was 0.16 mol/L,and volume ratio of membrane solution to stripping solution was 30:30 of the renewal phase,and pH value was 4.80 of the feed phase.Under the optimum condition studied, when initial concentration of Gd（Ⅲ） was 1.00×10^-4 mol/L,the transfer rate of Gd（Ⅲ） was 96.8%during 130 min.     

微乳法制备纳米TiO2 /SiO2的结构及光催化研究

Nanosized TiO₂ and TiO₂/SiO₂ particles were prepared by hydrolysis of tetrabutyl titanate (TBOT) and tetraethyl orthosilicate (TEOS) in the TX-100 reverse microemulsion. These particles were characterized by TG-DSC, XRD, FTIR, TEM，N₂ adsorption-desorption. Their photocatalytic activity was tested by degradation of methyl orange. The result shows that TiO₂/SiO₂ nanoparticles are with a monodispersed spherical phase and a uniform size distribution，and TiO₂ particles are dispersed on the surface of SiO₂. The band for Ti-O-Si vibration in FTIR was observed, the Ti-O-Si bond increased the stability of anatase TiO₂, suppressed the phase transformation of titania from anatase to rutile. And due to the addition of SiO₂, the average size of titania decreased from 38 nm in pure TiO₂ to 5 nm in TiO₂/SiO₂. It was found, under UV light irradiation, TiO₂/SiO₂ particles showed higher activity than pure TiO₂, and TiO₂/SiO₂(1/1) particles showed the highest photocatalytic activity on the photocatalytic decomposition of methyl orange, which was influenced by crystal structure, particle size, crystallinity and Surface area Characteristics.     

EFFECT OF DILUENTS ON CRYSTALLIZATION OF POLY(VINYLIDENE FLUORIDE) AND PHASE SEPARATED STRUCTURE IN A TERNARY SYSTEM via THERMALLY INDUCED PHASE SEPARATION

The phase diagram of a ternary system of PVDF,dibutyl phthalate (DBP) and di(2-ethylhexyl) phthalate (DEHP) was determined in terms of a pseudo binary system with the same polymer concentration and different DBP content in diluent mixture.The experimental results showed that as the DBP content increased in diluent mixture,the phase separation changed from liquid-liquid phase separation to solid-liquid phase separation,and both the cloudy point for L-L phase separation and crystallization temperature shif...     

CeOHCO3和CeO2束状纳米结构的制备及表征

The cantaloupe-like particles of CeOHCO₃ were synthesized in aqueous solution by using cetyltrimethylammonium bromide (CTAB) as soft template. Then, the bunchiness rods of CeO₂ were obtained by calcining CeOHCO₃ at 450 ℃. The results of thermogravimetric/differential thermal analysis reveal that an endothermic reaction with decomposition is involved in the transformation process from CeOHCO₃ to CeO₂. By scanning electron microscopy and X-ray diffraction analysis, it is found that the orthorhombic phase CeOHCO₃ particles are constituted of short nanorods with diameters ranging from several tens nm to over 100 nm, and the cubic phase CeO₂ rods are composed of small particles with diameter ca. 15 nm. From the results of UV-Vis absorption and photoluminescence analysis, it is found that the CeO₂ possess abundant defects, and the band gaps of the CeO₂ and CeOHCO₃ are ca. 2.70 eV and 3.87 eV, respectively.     

离子层气相反应法(ILGAR)制备CuInS2薄膜的研究

CuInS₂ thin films have been prepared by ion layer gas reaction (ILGAR) using C₂H₅OH as solvent, CuCl and InCl₃ as reagents and H₂S gas as sulfuration source. The effects of cationic concentrations and numbers of cycle on the properties of CuInS₂ film were investigated. The chemical composition, crystalline structure, surface topography, deposited rate, optical and electronic properties of the films were characterized by X-ray diffractrometry (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), ultraviolet-visible spectrometry (UV-Vis) and Hall System. The results show that the crystalline of CuInS₂ thin films and the deposition rate have been improved with the increase of cationic concentration, while CuxS segregation phases appear with further increasing cationic concentration. The deposition rate is close to constant as cationic concentration is fixed. CuInS₂ thin film derived form lower cationic concentration is uniform, compact and good in adhesion to the substrates. The absorption coefficient of CuInS₂ thin films is larger than 10⁴ cm^-1, and the band gap E_g is in the range of 1.30～1.40 eV. The dark resisitivity of the thin film decreases from 50 to 10 Ω·cm and the carrier concentration ranges are over 10¹⁶ cm^-3.     

分子内桥连有机钴配合物的合成及热稳定性研究

The intramolecularly bridged alkyl cobaltic complexes are one of important coenzyme B₁₂ model coplexes. In this paper, study on the thermolytic reaction of aqua(3-bromopropyl)cobaloximes in solution revealed that a new intramolecularly bridged alkyl cobaloximes complex was formed and the reaction is influenced by tempertature and solvent. Adding cyclodxtrin has no obvious effect to the rate of the reaction, but various products with different axial bases were obtained. The intramolecularly bridged alkyl cobaloxime complex (bromo(O-trimethylene-dimethy- lglyoxime)(dimethylglyoximate)cobalt(Ⅲ)) was characterized by EA and ESI-MS. Thermogravimetric analysis of this complex found that a carbon radical that from homolysis of the Co-C bond is retained in the proximity of Co^Ⅱ- complex, which is very similar to the behavior of coenzyme B₁₂.     

Schiff 碱双核配合物的磁性及催化性能的研究

This paper reports the catalytic properties of “porphyrin-like” Schiff base mononuclear complexes MH₂L {M=Mn(Ⅱ), Fe(Ⅲ)Cl, Cr(Ⅲ)Cl, Cu(Ⅱ), Co(Ⅱ), Ni(Ⅱ), Zn(Ⅱ); L=bis[N, N′-ethylene-2, 2′-(phenylmethylene)bis(3,4-dimethylpyrrole-5-aldimino)]} and dinuclear complexes MnML [M=Mn(Ⅱ), Fe(Ⅲ)Cl, Cr(Ⅲ)Cl, Cu(Ⅱ), Co(Ⅱ), Ni(Ⅱ), Zn(Ⅱ)] for cyclohexane monooxygenation with PhIO and magnetic properties of the dinuclear complexes. The magnetic investigations (4～300 K) of the dinuclear complexes revealed that their antiferromagnetic spin exchange with J ranged from -10.49 to -0.482 cm^-1 except MnZnL and antiferromagnetic spin exchange decreased in the following order: Mn^Ⅱ-Cu^Ⅱ > Mn^Ⅱ-Ni^Ⅱ > Mn^Ⅱ-Mn^Ⅱ > Mn^Ⅱ-Fe^Ⅲ > Mn^Ⅱ-Co^Ⅱ > Mn^Ⅱ-Cr^Ⅲ. The results of catalyzed oxidation of cyclohexane indicated that the catalytic property of the dinuclear complex was better than that of the corresponding mononuclear complex. It was found that there was the synergism decreased in the order: Mn-Fe > Mn-Cr > Mn-Cu > Mn-Mn > Mn-Co> Mn-Ni > Mn-Zn. It seems that this synergism increases with the increase of the number of unpaired d electrons and the magnetic exchange between the two metals in these dinuclear complexes.     

N2O活化的Fe/ZSM-5表面活性氧的表征(英)

Temperature-programmed reduction (H₂-TPR) was employed to quantitatively characterize the active oxygen species generated from a high Fe-loading Fe/ZSM-5 catalyst exposed to N₂O at 250 ℃. [Fe-O-Fe]²⁺ dimer was determined as the active iron complex for N₂O decomposition to produce the active oxygen. Reduction of Fe³⁺ to Fe²⁺ by H₂ in the dimer and removal of OH^- groups from Fe²⁺ dimer by heating Fe/ZSM-5 to 700 ℃ were the prerequisites for the formation of this active Fe complex. A linear correlation with a slope of 1.0 between the amount of [Fe-O-Fe]²⁺ and that of active oxygen species was observed. Maximum amount of active oxygen species can be generated by reducing Fe/ZSM-5 catalyst with H₂ at the temperatures over 500 ℃ and then heating the resulting product in Ar to 700 ℃, followed by N₂O exposure at 250 ℃. The ratio of the total number of oxygen atoms (Ode) deposited by interaction of [Fe-O-Fe]²⁺ with N₂O to the amount of [Fe-O-Fe]²⁺ was 2. However, not all the deposited oxygen atoms were active oxygen (O_a); the ratio of O_a and O_de was 0.5. The iron dimer complex composing active oxygen is a five-atom ion [Fe₂O₃]²⁺; the most probable structure is as follows:     

Development and Application of a Two-Phase Clean-Up System in Food Samples Prior to Fluorescence Analysis of Aflatoxins

A new method based on the use of a two-phase separation system is proposed for the clean-up of aflatoxins after their extraction from food samples. After extraction from the sample with an appropriate solvent, aflatoxins contained in organic solvent diffuse to the aqueous phase. At that stage their relative concentration is measured fluorimetrically at 350 nm (λ_exc). Different organic solvents were tested, and the composition of the aqueous phase was varied. The data obtained showed that the best efficiencies were observed with toluene and PBS-65% methanol. The method was simpler and shorter, and capable of monitoring aflatoxins in samples with a LOD equal to 0.3 μg kg⁻¹ (AFB₁). However, the proposed method shows limited selectivity and could thus serve as a screening method for total aflatoxins or be combined with chromatographic techniques for individual aflatoxin determination.     

La2(CO3)3纳米线的微乳液法制备与表征

La₂(CO₃)₃ nanowires were prepared in the nonionic surfactant microemulsion(Triton X-100/cyclohexane/water)system. Transmission electron microscopy (TEM) and selected area electronic diffraction (SAED) were used to characterize the shape and size of the products. The results showed that the pH value and concentration of mother solution, temperature and aging time all could affect the morphology and size of the La₂(CO₃)₃ nanowires. The lengths of the nanowires were more than 10 μm and the diameters were in the range of 30～200 nm.     

Nafion? / TiO2复合膜的质子传导性能研究

Nafion^® / TiO₂ composite membranes were prepared by in-situ chemical reaction method using Ti(OC₄H₉)₄ and Nafion^® 117 as raw materials. The membranes were characterized by UV, FTIR-ATR and XRD, respectively. Methanol permeability and water uptake were investigated as a function of TiO₂ contents. The conductivity of the membranes was measured under water vapor pressure (2.644 7 kPa) or in dry atmospheres. The XRD results showed that the titanium dioxide in Nafion^® membranes were crystallized in anatase phase with an average crystaline diameter of 3.0 nm. The water uptake of the composite membranes was larger than that of the pure Nafion^® membrane when the TiO₂ loading was within 14wt%. The methanol permeability of the membrane decreased as the TiO₂ loading increased. The addition of 3wt% TiO₂ to Nafion^® membranes improved the conductivity in dry measurement conditions. The proton conductivity of the composite membrane increased greatly after the hydrothermal treatment at 160 ℃ for 2 hours.     

STUDY ON TRANSPORT AND SEPARATION OF MO(Ⅵ) ION BY USING ELM OF TOA-SPAN 80-OXYLENE

A new ELM was prepared for the study on transport of Mo(Ⅵ) ion. Under the experimental conditions, Mo(Ⅵ) can be transported completely and separated from the co-lons.The emulsion liquid membrane(ELM) with Tri-n-octylamine(TOA) as a carrier used for the transport of Mo(Ⅵ) ions and its separation from some cations have been reported in this paper. The transport percentage of Mo(Ⅵ) ion through ELM in 5 min corresponds to that of the literature in 165 min.