Induced Co-colouration and Induced Co-decolouration between Different Rare Earths in the System of 《Metal(Ⅱ)-Rare Earth(Ⅲ)-Chromophoric Reagent-Sensitizer》

In co-colouration systems of rare earth(Ⅲ) with a metal(Ⅱ), induced colouration and decolouration ef-fects between different rare earths have been discovered. A sensitive co-colouration system of 《Lead(Ⅱ)-RareEarth(Ⅲ)-Alizarin Violet-Sensitizer》 was chosen as a typical one to study; and neodymium, gadolinium andyttrium were used to represent light, middle and heavy rare earths respectively. Semiquantitative relationshipsfor the induced effects between yttrium and neodymium as well as between gadolinium and neodymium havebeen determined and discussed. In the presence of a sensitizer, these metal ions cannot always be coloured byalizarin violet when each of them is present alone, but a very sensitive co-colouration or co-decolouration mayoccur during their coexistence under certain conditions. If these metals exist as foreign ions in the photometricdetermination of another metal, serious unperceivable interference will possibly occur. Moreover, the condi-tions leading to induced co-colouration and co-decolouration are very complicated, so that close attention mustbe paid to this area in the photometric determination of certain metals.     

Elution of lead from vermiculite with environmentally benign reagents

The elution of lead from vermiculite was investigated by using a novel biodegradable chelating reagent,L-asparagic-N,N-diacetic acid(ASDA)and water soluble depolymerized pectic acid and comparing with a conventional chelating reatent,EDTA,as well as acetic acid.The influences of the reagent concentration,equilibrium pH and the suspension contact time on Pb extraction were examined.It is concluded that the acetic acid is not effective for Pb removal in any case due to its weak complexing ability with Pb.Although Pb is easier to be released by EDTA with stoichiometric amount,it is by no means the preferable alternative for the purpose because of its low biodegradability.On he other hand,ASDA and depolymerized pectic acid have the potential application because they are not only effective for Pb elution but also environmentally friendly.     

Crystal structure and thermal stability of martensite in Cu-25Al-3Mn alloy

The martensite structure in Cu-25Al-3Mn alloy and its thermal cycling and aging behavior are studied. It is convinced that the M2H martensite can be obtained by water-quenched, and the atoms distribution on the basal plane of the mart ensite is: Ⅰ(corner)-Al; Ⅱ(center of the plane)-Cu; Ⅲ(middle of b- side)-22/25Cu+3/25Mn. The lattice parameters are determined to be a=0.445 9 nm, b=0.527 9 nm, c=0.424 1 nm, β=88.64°. The triangle and other complicated configurations consisting of the variant group in the martensite are discovered. It is showed that the tested alloy has a high thermal stability when aging at average temperature in the parent phase, and the thermoelastic martensite amount is up to 90% af ter aging for 96 hat 400 ℃. The thermal cycling has a little influence on the transform ation temperature (Ms). When the number of thermal cycles is up to 1000, the increasing of Ms is only 8 ℃.     

Separation of indium (Ⅲ), gallium (Ⅲ), and zinc (Ⅱ) with Levextrel resin containing di(2-ethylhexyl) phosphoric acid (CL-P204): Part I. Selection of separation conditions

A kind of Levextrel resin separation process was developed for separation of indium (Ⅲ), gallium (Ⅲ), and zinc (Ⅱ) from aqueous sulfate solution with Levextrel resin containing di(2-ethylhexyl) phosphoric acid (CL-P204). The aim of the research is to collect preliminary results for a pilot-scale production. Properties of adsorbing indium (Ⅲ), gallium (Ⅲ), and zinc (Ⅱ) from sulfate solution with the Levextrel resin were first studied by batch operation and column operation. The optimum pH, adsorption capacities and concentrations of stripping agents for indium (Ⅲ), gallium (Ⅲ) were tested. The separation order of indium (Ⅲ), gallium (Ⅲ), and zinc (Ⅱ) from sulfate solution with CL-P204 Levextrel resin was found that indium (Ⅲ) could be first separated by adsorbing at the acidity of 1.0 mol/L whereas gallium (Ⅲ) and zinc (Ⅱ) could not, and they were adsorbed together by adsorbing at pH = 2.8, then separated from each other by stripping with 0.1 and 0.5 mol/L hydrochloric acid, respectively. T     

Sensitizing Effect of Mixed Surfactants on the Colouration of Scandium(Ⅲ)with Phenylfluorone or Its Derivatives

In the presence of mixed micelle of a cationic and a nonionic surfactants,the reaction of scandium(Ⅲ)with phenylfluorone or its derivatives results in a very sensitive colouration:furthermore this chromophoricsystem tolerates the existence of a considerable amount of masking agents,so that many interfering ions can bemasked and its selectivity would be further improved.After studying the optimum conditions and main charac-ters of some similar systems,the system of Sc(Ⅲ)—Orthonitrophenyuorone—CetyltrimethylammoniumBromide(CTMAB)—Triton X-200 is chosen for the spectrophotometric determination of microamount ofscandium.The proposed method shows not only high sensitivity(with a molar absorptivity of 2.12×1~sLmol~(-1)·cm~(-1))and selectivity,but also high tolerance of chromophoric conditions.Beer's law is obeyed over arange of 0～6.0 μg Sc/25ml.If the dual-wavelength method is applied,a much higher molar absorptivity o|"3.04×10~5L·mol~(-1)·cm~(-1)than those of other systems ever reported in the literatures can be attained:more-over.its linear range is extended to 0～8.0 μg Sc/25ml and its reproducibility is also improved.     

Separation of indium(Ⅲ),gallium (Ⅲ),and zinc(Ⅱ)with Levextrel resin containing di(2-ethylhexyl)phosphoric acid(CL-P204):Part Ⅰ. Selection of separation conditions

A kind of Levextrel resin separation process was developed for separation of indium (Ⅲ), gallium (Ⅲ), and zinc (Ⅱ) from aqueous sulfate solution with Levextrel resin containing di(2-ethylhexyl) phosphoric acid (CL-P204). The aim of the research is to collect preliminary results for a pilot-scale production. Properties of adsorbing indium (Ⅲ), gallium (Ⅲ),and zinc (Ⅱ) from sulfate solution with the Levextrel resin were first studied by batch operation and column operation. The optimum pH, adsorption capacities and concentrations of stripping agents for indium (Ⅲ), gallim (Ⅲ) were tested. The separation order of indium (Ⅲ), gallim (Ⅲ), and zinc (Ⅱ) from sulfate solution with CL-P204 Levextrel resin was found that indium (Ⅲ) could be first separated by adsorbing at the acidity of 1.0 mol/L whereas gallium (Ⅲ) and zinc (Ⅱ) could not, and they were adsorbed together by adsorbing at pH = 2.8, then separated from each other by stripping with 0.1 and 0.5mol/L hydrochloric acid, respectively. The recoveries of three metal ions were all higher than 99%. The cyclic properties of this resin are well.     

Comparative study on biosorption of Pb(Ⅱ) and Cr(Ⅵ) by Synechococcus sp.

The comparative study on adsorptions of Pb(Ⅱ) and Cr(Ⅵ) ions by free cells and immobilized cells of Synechococcus sp.was performed,in which different aspects including Zeta potential of the cells,the influence of pH,temperature and initial concentration of metal ions,as well as adsorption kinetics and mechanism were referred.The lyophilized free cells have a surface isoelectric point at pH 3,and the correlative experiment indicates that there is an electrostatic adsorption feature of Cr(Ⅵ) and Pb(Ⅱ).The immobilization of the free cells by Ca-alginate does not significantly modify the adsorption features of the biosorbent.The absorption processes of Cr(Ⅵ) and Pb(Ⅱ) on both free and immobilized cells are apparently affected by pH and the initial concentration of metal ions in the bulk solution,but are much weakly affected by temperature in the test range of 10-50 ℃.The slow course of biosorption follows the first order kinetic model,the adsorption of Pb(Ⅱ) obeys both Langmuir and Freundlich isotherm models,while the adsorption of Cr(Ⅵ) obeys only Freundlich model.FT-IR results indicate that carboxylic,alcoholic,amide and amino groups are responsible for the binding of the metal ions,and reduction of Cr(Ⅵ) to Cr(Ⅲ) takes place after Cr(Ⅵ) adsorbs electrostatically onto the surface of the biosorbents.     

Extraction equilibria and kinetics of Ti(Ⅳ) from leached chloride liquors of ilmenite

Extraction of titanium(Ⅳ)from real chloride leach liquor of ilmenite was carried out with 0.1 mol L~(-1)di-(2-ethylhexyl)phosphoric acid(HDEHP)in kerosene.Equilibrium and kinetics studies for Ti(Ⅳ)were carried out in the presence of impurities that were leached with Ti(Ⅳ).Parameters affecting extraction rate of Ti(Ⅳ)from chloride media in the presence of Fe(Ⅲ),Mg(Ⅱ),and Al(Ⅲ)were studied to evaluate the stoichiometry of extracted Ti(Ⅳ)species.It is found that the extraction rate of Ti(Ⅳ)is dependent on the extractant concentration and pH of solution.Under the optimum conditions,more than 95%Ti(Ⅳ)can be extracted.On the basis of slope analysis method,the extracted species of Ti(Ⅳ)appears to be[TiO(H_2A_2)_2]_(org),where H_2A_2 refers to HDEHP.Further,the kinetic studies of the extraction process of Ti(Ⅳ)and other metal ion impurities were carried out by a Lewis cell with a constant interfacial area of 16.7 cm~2.Analysis of the experimental results suggests that TiO~(2+)extraction rate by HDEHP is the first with respect to hydrogen ion concentration and HDEHP concentration.The results are interpreted by a reaction mechanism where the extraction process is controlled by a diffusion process at the interface rather than in the bulk phase.     

Adsorption of Au(Ⅲ) by amino-modified monodispersed PGMA microspheres and deposition of gold nanoparticles

Monodispersed poly(glycidyl methacrylate)(PGMA) microspheres with various amounts of amino groups(PGMA-NH_2) were used to adsorb Au(Ⅲ) from simulated wastewaters. Gold nanoparticle-coated PGMA functional microspheres can be directly obtained via the adsorption process. The adsorption kinetics follows pseudo-second model, and 10 min is enough for reaching at equilibrium. The adsorption isotherm follows Langmuir model, and the adsorption amounts for Au(Ⅲ) are 8.25 and 21.75 mol·kg^-1 at 298 and 328 K, respectively. The relative separation coefficients between Au(Ⅲ), Pt(Ⅵ), Pd(Ⅱ)and Co(Ⅱ), Cu(Ⅱ); Ni(Ⅱ), Fe(Ⅲ) are all higher than 100 when 1 < pH < 3. Furthermore, the characterization analysis of X-ray diffraction(XRD), thermogravimetrydifferential scanning calorimetry(TG-DSC), scanning electron microscopy-energy dispersive spectroscopy(SEM-EDS), transmission electron microscopy(TEM) and Fourier transform infrared spectroscopy(FTIR) confirms that AuCl_4^-has been reduced to Au^0 nanoparticles and deposited onto the surface of PGMA-NH_2. The current work shows a good prospect for PGMA-NH_2 to be a valid adsorbent for the recovery of gold and the possible fabrication of gold nanoparticles by reduction-deposition process without any reductant.     

SOLVENT EXTRACTION OF Fe(Ⅲ) FROM SULFATE SOLUTIONS WITH TERTIARY AMINE

The tertiary amine can be used to extract Fe(Ⅲ) very effectively in the pH range resulting inpartial hydrolysis of Fe~(3+) ions.The iron extracted into the organic phase can be strippedrather easily with dilute H_2SO_4 or even with H_2O.Fe(Ⅲ) is extracted into the tertiary aminesulfate solution in the form of[(R_3NH)_2Fe(OH)(SO_4)_2]_2 complex by adduct formation.Equa-tion was derived to represent the chemical reactions involved during extraction.From theinfrared spectrum studies on the extraction species in waxy solid form separated from the so-lution,sulfate group is a bidentate ligand to the iron atom.The extraction species has beenconsidered to contain (FeOH)_2 unit based on the ultra violet spectra.The possible structure ofthe extraction species has been proposed.     

Electrochemical investigation on the formations of Dy-Ni alloy films in dimethylformamide

The electrochemical properties of Dy(Ⅲ), Ni(Ⅱ) and Dy(Ⅲ) Ni(Ⅱ) in dimethylformamide were studied by cyclic voltammetry on Pt or Cu electrode. Black, metallic lustered, compact and well adhesive Dy-Ni alloy films can be co-deposited on Cu electrode by sweeping-potential-deposition method within some potentials. SEM, EDAX and XRD were used to analyze the alloy films. The Dy content in the Dy-Ni alloy film is up to 56.91%(mass fraction) and the DyNi alloy films are amorphous.     

Corrosive electrochemistry of jamesonite

The corrosive electrochemistry of jamesonite (Pb4FeSb6S14 ) was studied by the electrochemical methods of cyclic voltammetry, polarization, and AC impedance. The electrochemical processes of jamesonite were controlled by the corrosive reactions, growth of the metal-deficient and sulfur-riched layer, passivation and breakdown of elemental sulfur film on the electrode surface. The corrosive potential(φcorr) moves negatively, its corrosive current increases, and hydroxyl action becomes stronger with the rising pH value. The charge transfer resistance increases and the capacitance decreases due to the gradual growth of the metal-deficient and sulfur-riched layer on the mineral surface from -378 to 122mV (vs SHE). Element sulfur layer is formed at the potential of 122 mV. The charge transfer resistance increases and its capacitance rises slowly due to the gradual breakdown of sulfur film at voltage from 222mV to 422mV. S2O3^2- and SO4^2- ions occur when the electrode potential is over 422 mV. Under basic condition, the hydrophobic hydroxyl precipitate occurs on jamesonite surface, so that its collectorless floatability is poor. Under the condition of pH6.86, it can be deduced that the potential range of collectorless floatability of jamesonite is from 22 to 422mV due to the passive action of the hydrophilic sulfur on jamesonite surface, and its optimum range of floatable potential is between 122 and 322mV.     

Simultaneous Determination of Zirconium and Hafnium by Dual System and Dual Wavelength Spectrophotometry

A dual system and dual wavelength spectrophotometry(DSDWS)used to simultaneously determine Zrand Hf were proposed.《Zr(Hf)-xO-CTMAB》and《Zr(Hf)-CAB-CDMAA-Triton X-100》were chosenas a pair of chromophoric systems.The difference of chromophoric behaviours between Zr and Hf is in-creased by the addition of hydrogen peroxide as masking agent and by adjustment of acidity.The apparentmolar absorptivities of Zr and Hf are 2.0×10~5 and 5.0×10~4 L·mol~(-1)·cm~(-1)respectively.The proce-dure is simple and rapid.     

Kinetic and thermodynamic studies of adsorption of gallium(Ⅲ) on nano-TiO_2

Nano-TiO2 was employed for the adsorption of gallium from aqueous solution in batch equilibrium experiments to investigate its adsorption properties. It was found that the adsorption efficiency of Ga(Ⅲ) was more than 96% at pH 3.0. The adsorption capacities and rates of Ga(Ⅲ) onto nano-TiO2 were evaluated as a function of solution concentration and temperature. The results were analyzed using the Langmuir adsorption isotherms. Adsorption isothermal data could be well interpreted by the Langmuir model. The mean energy of adsorption, 15.81 kJ·mol-1, was calculated from the D-R adsorption isotherm. The kinetic experimental data properly correlate with the pseudo-second-order kinetic model. The thermodynamic parameters for the process of adsorption have been estimated. The △ H Οand △ GΟvalues of gallium(Ⅲ) adsorption on nano-TiO2 showed an endothermic and spontaneous nature of adsorption.     

Extraction of palladium（Ⅱ） with OTMSO from acidic media

The extraction of palladium(Ⅱ) from acidic media with cyclic sulfoxide deriva-tive-α-octyl-tetrahydrothiophene-Ⅰ-oxide (OTMSO) was investigated. The extraction efficiency of palla-dium(Ⅱ) with OTMSO is 97.1% at 0.3mol·L~(-1) OTMSO. The plots of the extraction efficiency for palla-dium(Ⅲ) appear to lie on a convex curve having a minimum of extraction efficiency at 1-2 mol·L~(-1) HCl. Theextraction reaction of palladium(Ⅱ) with OTMSO is endothermic, and ΔH_(OTMSO)~=12.2kJ·mol~(-1). The coor-dination number was studied with slope method. The result indicates that coordination number is 2. FT-IRspectra were used to analyze the structure of complex and coordinated atom in complex. Pd is coordinated withboth oxygen and sulfur atom in S=O group in OTMSO. The situation and intensity of peaks contributed bycomplex prepared from various acidity were different. The recovery of palladium(Ⅱ) with OTMSO from scrapcontaining palladium was discussed. After silver and bismuth were removed, the feed solution w     

Electrochemical properties of M1Ni_(3.5)Co_(0.6)Mn_(0.4)Al_(0.5)–x wt%Mm_(0.89)Mg_(0.11)Ni_(2.97)Mn_(0.14)Al_(0.20)Co_(0.54)composites

In order to improve the overall electrochemical properties of AB5-type storage alloys, the new type composite alloys M1Ni3.5Co0.6Mn0.4Al0.5–x wt% Mm0.89-Mg0.11-Ni2.97Mn0.14Al0.20Co0.54(x = 0, 5, 10; M1 means mischmetal) were prepared by means of ball milling. The composite alloys are shown to be single La Ni5 phase by X-ray diffraction(XRD) patterns. The maximum discharge capacity slightly increases from 315 m Ah g-1for M1Ni3.5Co0.6Mn0.4Al0.5to 324 m Ah g-1(x = 5) and325 m Ah g-1(x = 10). The addition of AB3-type La–Mg–Ni-based alloy has a positive effect on the cycle stability.With the addition of Mm0.89Mg0.11Ni2.97Mn0.14-Al0.20Co0.54 alloy, the exchange current density(I0), the limiting current density(IL), and the diffusion coefficient of hydrogen(D) of the alloy electrodes increase, leading to a corresponding improvement of the high rate dischargeability.     

Influences of complex modification of P and RE on microstructure and mechanical properties of hypereutectic Al-20Si alloy

P and RE complex modification of hypereutectic A1-Si alloys was conducted. The influences of P, RE content on the microstructure and mechanical properties of alloys were investigated. The complex modifications of P and RE make the coarse block primary silicon obviously refined and the large needle eutectic silicon modified to the fine fibrous or lamella ones. P mainly refines the primary silicon, but excess P is unfavorable to the refinement of primary silicon. RE can well refine the primary and eutectic silicon, but its modification effect on the eutectic silicon is more obvious. P can repress the modification of RE on the eutectic silicon The alloys with the additions of 0.08% P and 0.60% RE have the optimal microstructure and the highest mechanical properties. Compared with the unmodified alloy, the primary silicon of alloys can be refined from 66.4 μm to 23.3μm and the eutectic silicon can be refined from 8.3 μm to 5.2μm. The tensile strength is improved from 256 MPa to 306 MPa and the elongation is improved from 0.35% to 0.48%.     

Relationship between the types of binary alloy phase diagrams of Ⅷ and IB group elements and the Mendeleev numbers

The relationship between the types of binary alloy phase diagrams of VIII and IB group elements and the Mendeleev numbers was discussed for the first time using the VIII and IB group elements as solvent metals (A) and the other elements as solute metals (B), basesd on their alloy phase diagram types. The Mendeleev numbers of the solvent metals and the solute metals were expressed as MA and MB, respectively. A two-dimension map of MA/MB was drawn. It is indi-cated that there is an oblique line in the map, which divides the binary alloy phase diagram types of solvent metals intotwo symmetry parts, the phase diagram types of the other elements with solvent metals located at the above or down ofthe line respectively, while on the line, ΔM= 0. The phase diagrams between the solvent metals basically are simple systems, mainly belong to the types of continues solid solution and the peritectic (about 40% for each type). The solvent metals can be divided into three groups: Co, lr, Rh, Ni, Pt, and Pd as the first group; Ag, Au, and Cu as the second group;and Fe, Os, and Ru as the third group. The characteristics of the phase diagrams formed between the elements in each group were discussed. About 80% phase diagrams belong to complex systems and less than 20% belong to the simple systems. The regular variation of the chemical scale, the metallic radii of the atoms, the number of valence electrons, and the first ionization energy with the Mendeleev numbers and the crystal structure were introduced as well.     

Complex Solid Superacid Catalyst WO_3-ZrO_2-SO_4~(2-) Structure of Acid Sites on the Catalyst

A new type of complex solid superacid catalyst WO_3-ZrO_2-SO_4~(2-)with an acid strength H_0≤-16.04 wasprepared by kneading Zr(OH)_4 or amorphous ZrO_2 with tungstic acid(H_2WO_4)(W/Zr=0.15),followed byexposing this complex hydroxides to 0.5 tool/L H_2SO_4,calcining in air at 700～800℃ for 3h.This catalystpossesses both strong Bronsted acidity and strong Lewis acidity experimentally showed by IR observation ofpyridine absorbed on it.XPS and AES techniques were employed to examine the valence states of tungsten,zirconium,sulfur and their interactions.The structure of sulfur species was studied by infrared spectroscopyand a structure model of active site was proposed upon these results.     

Effect of the Mass Ratio of CaCO3 to CaHPO4·2H2O on in Situ Synthesis of Hydroxyapatite Coating by Laser Cladding

Hydroxyapatite coatings were fabricated on Ti substrates by laser cladding (LC) using mixed powders of CaCO3 and dicalcium phosphate dihydrate (DCPD, CaHPO4·2H2O). The effect of the mass ratio of CaCO3 to DCPD on phase and microstructure formation of the coatings was investigated. The reactions between CaCO3 and DCPD can produce high crystallized hydroxyapatite (HA, Ca5(PO4)3(OH)) in the coatings as well as tetracalcium phosphate (TTCP, Ca4P2O9), α-tricalcium phosphate (α-TCP, α-Ca3(PO4)2), β-tricalcium phosphate (β-TCP, β-Ca3(PO4)2) and Ca2P2O7. The Ca/P molar ratio (CMR) of the mixed powders (CMRP) has a great influence on the contents of the phases in the coating. HA can be produced in the coating only when the CMRP is higher than 1.54, and its content increases slowly as the CMRP increases. The coating contains only about 25wt% HA when CMRP reaches 2.00, and there exists large amount of TTCP in the coating. So a post heat treatment with furnace cooling is recommended to increase the amount of HA in the coating. All the coatings have porous structures because the reactions between the powders produce lots of gases during LC. The pore size in the coating fabricated by the powders with CMR equal to 2.00 is about 100-300 mm. CMRP also has a great influence on the bond strength, porosity and cracks of the coatings. Along with the increase of the CMRP, the bond strength and porosity decrease, whereas the number of cracks increases