Elution Behavior of Metal Ions with Mixed Glycine-Nitric Acid Eluents in Dowex 50W-X8 Column: Separation of Th(IV), Ce(IV), Bi(III), Fe(III), and Al(III)

Abstract

Distribution coefficients (K) determined by the batch technique in acidic glycine media using Dowex 50W-X8 cation exchanger (H⁺?form, 100–200 mesh size) revealed that this medium can effectively be employed to separate a number of tetravalent and trivalent metal ions from bivalent metal ions. In fixed glycine (0.40 M) and varying concentration of nitric acid (0.10 to 1.0 M), a number of mixtures containing two or three metal ions were resolved on columns using about 8 g of exchanger. In 0.40 M glycine-1.0 M HNO₃ medium, Th(IV)/Ce(IV) were separated from Al(III)/Fe(III)/Bi(III)/Co(II)/Ni(II)/Cu(II)/Zn(II)/Cd(II)/Hg(II)/Pb(II)/Ag(I) and also Al(III)/Bi(III) from a number of divalent metal ions. In 0.40 M glycine-0.50 M HNO₃ medium, the resolution of following ternary mixtures were also achieved: Th(IV)/Ce(IV)-Al(III)/Bi(III)-Fe(III)/Co(II)/Ni(II)/Cu(II)/Zn(II)/Cd(II)/Hg(II)/Pb(II)/Ag(I). Th(IV)/Al(III)/Fe(III)/Bi(III) were also separated from other divalent metal ions in 1.60 M glycine-0.50 M HNO₃ medium. The values of K, elution characteristics of metal ions, elution curves, and the results of the resolution of a number of mixtures of metal ions along with standard deviations are reported.     

Properties of Poly(vinyl chloride)/poly(ethylene oxide)/polyaniline Conductive Films: The Effect of Poly(ethylene glycol) Diglycidyl Ether

The effect of polyaniline and poly(ethylene glycol) diglycidyl ether on tensile properties, morphology, thermal degradation, and electrical conductivity of poly(vinyl chloride)/poly(ethylene oxide)/polyaniline conductive films was studied. The poly(vinyl chloride)/poly(ethylene oxide)/polyaniline conductive films were prepared using a solution casting technique at room temperature until a homogeneous solution was produced. Poly(vinyl chloride)/poly(ethylene oxide)/polyaniline/poly(ethylene glycol) diglycidyl ether conductive films exhibit higher electrical properties, tensile strength, modulus of elasticity but lower final decomposition temperature than poly(vinyl chloride)/poly(ethylene oxide)/polyaniline conductive films. Scanning electron microscopy morphology showed that the polyaniline more widely dispersed in the poly(vinyl chloride)/poly(ethylene oxide) blends with the addition of poly(ethylene glycol) diglycidyl ether as surface modifier.     

PBT共混改性研究最新进展

综述了最近几年国内外聚对苯二甲酸丁二醇酯(PBT)共混改性的研究进展,分类介绍PBT/聚烯烃、PBT/同系聚酯、PBT/液晶、PBT/弹性体、PBT/聚碳酸酯等不同共混体系,讨论了各体系中的相行为、相容性、热稳定性、力学性能等,并对该类共混物的发展趋势作了简要的分析。     

C_3S-S-H系统水化产物的热力学稳定性

依据高C3S水泥和混合材复合体系的组成特征,用热力学方法分析了C3S-S-H系统在不同n(Ca)/n(Si)组成时的水化反应.结果表明,C3S-S-H系统水化产物的稳定性由系统n(Ca)/n(Si)组成决定,当n(Ca)/n(Si)>1.88时,最稳定的水化产物是C2SH1.17;当1.25相似文献   

煤与天然气气流床共气化制合成气试验研究

为提高煤、天然气资源综合利用效率,优化合成气成分,进行了煤与天然气气流床共气化技术研究。介绍了煤与天然气气流床共气化的试验装置及工艺流程,考察了气化温度、压力、水煤浆浓度、CH4与煤比对共气化反应的影响。结果表明,气化温度和CH4与煤比是共气化反应的主要影响因素,较高的气化温度对共气化反应有利,气化温度为1 350℃时,共气化指标较好,有效气体积分数大于90%;随着CH4与煤比的增大,合成气n(H2)/n(CO)增高。CH4与煤比为0.9 m3/kg时,合成气中n(H2)/n(CO)约1.2。根据后续合成工艺要求,通过调节气化温度和CH4与煤比,可获得n(H2)/n(CO)在0.8~2.0的合成气。     

Synthesis and Characteristics of SiC/MnO2/PS/PC QuaternaryNanostructures for Advanced Nanodielectrics Fields

Silicon - This work aims to synthesize of silicon carbide(SiC)/manganese oxide(MnO2)/polystyrene(PS)/ polycarbonate(PC) quaternarynanostructures to use in various advanced electronics nanodevices....     

SnO2 nanorod arrays: low temperature growth, surface modification and field emission properties

SnO(2) nanorod arrays have been deposited on 4 inch SiO(2)/Si and Si wafers and stainless steel substrates by plasma-enhanced chemical vapor deposition without any high temperature treatment or additional catalysis. The SnO(2) nanorods grow up from seed nanocrystals along the [110] preferential direction by a self-catalyzed vapor-solid growth mechanism. The surface of the SnO(2) nanorods was modified by ZnO, Pt and Ni nanocrystals. After surface modification, the field emission properties of the SnO(2) nanorod arrays are improved. The Ni nanocrystal with sharp tips and edges act as additional field emission sites to SnO(2) nanorods and thus the Ni/SnO(2)/SiO(2)/Si outperforms other samples due to the synergistic effects of good conductivity and hierarchical sharp apexes. The field enhancement factor of the Ni/SnO(2)/SiO(2)/Si increased around 3 times while the turn-on field of 8.0 V μm(-1) is about one third of the SnO(2)/SiO(2)/Si device.     

Highly active methanol decomposition catalyst derived from Pd‐hydrotalcite dispersed on mesoporous silica

Pd‐hydrotalcite (abbreviated as Pd(HT)) was dispersed on HMS (hexagonal mesoporous silica) by synthesizing Pd(HT) in an HMS suspension, and the resultant product (Pd(HT)/HMS) was used as a catalyst precursor for methanol decomposition to synthesis gas. The IR spectra of Pd(HT)/HMS showed all the bands of Pd(HT) and HMS with little shift, which indicated that Pd(HT) was synthesized in the Pd(HT)/HMS. Pd(HT)/HMS did not show the XRD pattern of Pd(HT) when the mass ratio of Pd(HT) to HMS was from 2/1 to 1/2. This indicated that Pd(HT) was formed in very small particles in the Pd(HT)/HMS after dispersion. Two endothermic peaks of Pd(HT) in the DTA curve shifted to lower temperatures in the Pd(HT)/HMS because the small Pd(HT) particles formed in the Pd(HT)/HMS were easily collapsed by heat treatment. Pd(HT)/HMS was thermally decomposed and reduced to form a supported Pd catalyst (abbreviated Pd(Mg(Al)O)/HMS) for methanol decomposition. Pd(Mg(Al)O)/HMS at 3.6 wt% showed a 52.5% conversion which was much higher than those over 3.6 wt% Pd(Mg(Al)O) (34.7%) and 3.6 wt% Pd/HMS (13.7%) for methanol decomposition at 523 K. The conversions of methanol over Pd(Mg(Al)O) and Pd/HMS increased with the increase in Pd loadings from 3.6 to 15 wt% and decreased when the Pd loadings were over 15 wt%. In contrast, the conversion over Pd(Mg(Al)O)/HMS increased with the increase in Pd loading even when the Pd loading was up to 30%. 30 wt% Pd(Mg(Al)O)/HMS showed a 91.7% conversion which was about twice that over 15 wt% Pd(Mg(Al)O) (47.1%) at 523 K. The Pd(Mg(Al)O)/HMS catalyst showed a larger BET surface area and Pd metal surface area than those of Pd(Mg(Al)O). By characterization using XPS analyses, the metal–support interaction between small Pd and small Mg(Al)O became stronger in the Pd(Mg(Al)O)/HMS catalyst. Large surface area, high Pd dispersion and strong metal–support interaction caused the high catalytic activity for methanol decomposition to synthesis gas over the Pd(Mg(Al)O)/HMS catalyst. This revised version was published online in July 2006 with corrections to the Cover Date.     

Impact,Thermal, and Morphological Properties of Poly(Lactic Acid)/Poly(Methyl Methacrylate)/Halloysite Nanotube Nanocomposites

Poly(lactic acid)/poly(methyl methacrylate) blends containing halloysite nanotube (2 and 5 phr) and epoxidized natural rubber (5–15 phr) were prepared by melt mixing. The impact strength of poly(lactic acid)/poly(methyl methacrylate) blend was slightly improved by the addition of halloysite nanotube. Adding epoxidized natural rubber further increased the impact strength of poly(lactic acid)/poly(methyl methacrylate)/halloysite nanotube nanocomposite. Single T_g of poly(lactic acid)/poly(methyl methacrylate) is observed and this indicates that poly(lactic acid)/poly(methyl methacrylate) blend is miscible. The addition of halloysite nanotube into poly(lactic acid)/poly(methyl methacrylate) slightly increased the T_g of the blends. The epoxidized natural rubber could encapsulate some of the halloysite nanotube and prevent the halloysite nanotube from breaking into shorter length tube during the melt shearing process.     

MCM-41负载Lewis酸催化合成2-甲基吲哚

以苯肼和丙酮为原料,在负载有各种Lewis酸的MCM-41分子筛催化下采用Fischer吲哚合成法合成2-甲基吲哚,在比较了AlCl3/MCM-41、ZnCl2/MCM-41和FeCl3/MCM-41对反应的选择性和收率后发现,负载量为4mmol/g的ZnCl2/MCM-41具有对反应较好的选择性,目标产物收率达到了76.2%。     

SiO2负载铬基催化剂催化四氢萘合成α-四氢萘酮

以硝酸铬或重铬酸钾为Cr源,采用浸渍法制备了SiO₂负载的Cr基催化剂［Cr(Ⅲ)/SiO₂和Cr(Ⅵ)/SiO₂］,并用共浸渍法制备了K₂O改性的Cr(Ⅲ)/SiO₂催化剂［K-Cr(Ⅲ)/SiO₂］。分别以叔丁基过氧化氢和O₂作氧化剂,考察了三种催化剂催化四氢萘合成α-四氢萘酮的反应性能。结果表明,以叔丁基过氧化氢作氧化剂时,Cr(Ⅲ)/SiO₂表现出最高的反应活性和选择性,K-Cr(Ⅲ)/SiO₂与Cr(Ⅵ)/SiO₂活性相近。紫外可见漫反射光谱表征结果表明,Cr(Ⅲ)/_SiO2具有最高的低价Cr物种（Cr［L］）和高价Cr物种（Cr［H］）比例,K₂O的引入抑制了Cr［L］物种的生成。推测以叔丁基过氧化氢作氧化剂时,四氢萘氧化生成α-四氢萘醇是反应速率控制步骤,Cr［L］物种可能是催化该反应的活性中心。以O₂作氧化剂时,Cr(Ⅲ)/SiO₂与Cr(Ⅵ)/SiO₂催化剂性能相近,说明O₂在相界面传质和（或）在催化剂表面吸附可能是反应的控制步骤。     

Solubility behavior of ternary systems of lipids in supercritical carbon dioxide

In this review, the phase behavior of lipids in ternary and higher systems was analyzed to determine the effect of operating parameters and feed composition on solubility behavior and separation efficiency. The ternary systems studied included two triglycerides (TG) (trilaurin (LLL)/tripalmitin (PPP), trimyristin (MMM)/PPP and LLL/MMM), two fatty acids (FA) (oleic acid (OA)/linoleic acid (LA)), two fatty acid methyl esters (FAME) (methyl myristate (MeM)/methyl palmitate (MeP) and methyl oleate (MeO)/methyl linoleate (MeL)), FA/TG (OA/triolein (OOO)) and FAME/FA (MeO/OA) in SCCO₂. The quaternary and quinary systems analyzed contained three TG (LLL/MMM/PPP), three glycerides (monoolein (MO)/diolein (DO)/OOO) and four TG (PPP/palmitoyl-dioleoylglycerol (POO)/oleoyl-dipalmitoylglycerol (PPO)/OOO), respectively, in SCCO₂. While solubility of the less soluble component increased in ternary systems of solid triglycerides in SCCO₂, that of the more soluble component decreased or was not affected. Solubility diminution was observed for both solutes in some liquid mixtures such as fatty acid (oleic acid/linoleic acid) and fatty acid ester (methyl oleate/methyl linoleate) mixtures. Solubility enhancement for one of the mixture components was also observed (for example, for oleic acid in the presence of methyl oleate). Separation efficiency was lower than that predicted by binary data when the solubility of the less soluble solute was enhanced in the mixture, whereas it was improved if the solubility of the more soluble component was enhanced as observed in quaternary glyceride mixtures.     

Electrochemical behaviour and glass formation in molten bisulphates

Molten bisulphates form an interesting class of low-temperature fused salts which quench to form glasses; some technical and theoretical applications of these systems are discussed. The NaHSO₄KHSO-₄ eutectic (46.5% KHSO₄, m.p. 125°C,T _g 25°C) is easy to study since at lower temperatures decomposition of the melt is retarded and supercooling readily occurs. The solvent properties of this eutectic towards both inorganic and organic solutes have been investigated. The oxidation states available to transition and post-transition metals were studied spectrophotometrically and voltametrically; the results show a very restricted pattern of redox chemistry. The (abbreviated) electrochemical series is V(V)/V(IV)>Mn(III)/Mn(II)>H(I)/H₂(O)>Ag(I)/Ag(O)>Mo(VI)/Mo(V)> Hg(I)/Hg(O)>Cu(II)/Cu(O)>Zn(II)/Zn(O). The Hammett acidity function,H ₀, was measured as in the range –1 to –2. Various factors influencing redox reactions in the melt are discussed.     

n(CH3)/n(Si)对甲基硅树脂防水性能的影响

以甲基三乙氧基硅烷和二甲基二乙氧基硅烷或羟基硅油为原料,分别制备了n(CH3)/n(Si)值为1·2、1·4、1·6的甲基硅树脂;考察了n(CH3)/n(Si)值对甲基硅树脂防水性能的影响。结果表明,以甲基三乙氧基硅烷和二甲基二乙氧基硅烷制备的甲基硅树脂,当n(CH3)/n(Si)值为1·2时,具有良好的防水性能;以甲基三乙氧基硅烷和羟基硅油为原料制备的甲基硅树脂,随着n(CH3)/n(Si)值的增大,经其处理的试件的吸水率比减小,与水的接触角增大;综合考虑吸水率比和耐碱性能,n(CH3)/n(Si)值为1·4的硅树脂具有最优的防水性能,并有望具有较持久的防水保护功能。     

β-cyclodextrin as a Partial Replacement of Phosphorus Flame Retardant for Poly(Lactic Acid)/Poly(Methyl Methacrylate): A More Environmental Friendly Flame-Retarded Blends

β-Cyclodextrin was used together with isopropylated triaryl phosphate ester flame retardant to improve the flame resistance of poly(lactic acid)/poly(methyl methacrylate). Poly(lactic acid)/poly(methyl methacrylate)/flame-retardant blend (with and without β-cyclodextrin) was evaluated using limiting oxygen index, Underwriters Laboratories-94 vertical burning test, scanning electron microscopy, and thermogravimetric analysis (in O₂ and N₂). The addition of β-cyclodextrin was able to reduce the amount of flame retardant required for poly(lactic acid)/poly(methyl methacrylate) blends to achieve self-extinguishing properties. The poly(lactic acid)/poly(methyl methacrylate)20/flame-retardant/β-cyclodextrin blends achieved Underwriters Laboratories-94, V-0, and limiting oxygen index value of 29.3%. A compact and wide coverage of char layer was formed on the burning surface of poly(lactic acid)/poly(methyl methacrylate)20/flame-retardant/β-cyclodextrin blends.     

500t/a中试规模制备小颗粒4A沸石的研究

在500 t/a的中试设备上,以全化学合成法进行了小颗粒4A沸石合成的中试放大实验。采用正交实验方法考察了原料配比A〔n(SiO2)/n(Al2O3)〕、B〔n(Na2O)/n(Al2O3)〕、C〔n(H2O)/n(Al2O3)〕及晶化时间D(t)对产品性能的影响。通过方差分析,确定出其最佳工艺条件为:n(SiO2)/n(Al2O3)=1.8～1.9,n(Na2O)/n(Al2O3)=3.2～3.4,n(H2O)/n(Al2O3)=80～100,t=20 min。工艺验证实验结果表明,该条件下的中试产品钙交换能力≥295 mg CaCO3/g干基,符合QB1767—2003的一级品标准。     

聚硅酸镁盐絮凝剂对印染废水的脱色研究

文章以硅酸钠、硫酸镁和硫酸铝为原料,制备复合型聚硅酸镁盐絮凝剂。重点研究了聚硅酸镁（PMSS）和聚硅酸铝镁（PAMSS）,并与单一镁盐和铝盐进行了对比试验。研究结果表明：在pH=12条件下,PAMSS[n（Mg）／n（A1）／n（Si）=O．5：0．5：1]和PMSS[n（Mg）／n（Si）=1：1]色度去除率均可达到95％以上,并且PAMSS[n（Mg）／n（A1）／n（Si）=O．5：0．5：1]在pH（6～14）范围内都具有良好的脱色效果。在碱性条件下,PAMSS是一种高效的无机高分子絮凝剂。     

高替代率竹焦油酚醛树脂的合成工艺研究

竹焦油是竹炭产业的副产物之一,富含酚类物质,可部分替代昂贵苯酚合成竹焦油酚醛树脂(BPF)。以n(苯酚)/n(甲醛)、竹焦油替代率、n(NaOH)/n(苯酚)和反应时间为试验因素,以BPF的黏度和游离酚含量、相应胶合板的胶接强度和甲醛释放量为考核指标,采用正交试验法优选合成高替代率环保型BPF的最佳工艺条件。结果表明:当n(苯酚)/n(甲醛)=2.0、竹焦油替代率为50%、n(NaOH)/n(苯酚)=0.35和反应时间为60 min时,由BPF胶粘剂压制而成的胶合板,其胶接强度和甲醛释放量分别达到GB/T 9846.3—2004标准中Ⅰ类胶合板和E0级的指标要求。     

氮杂环苯基吡啶类铱配合物合成及器件性能

通过对2-甲基-8-(2-吡啶基)苯并呋喃[2,3-B]吡啶辅助配体进行修饰,在吡啶的4号位引入吸电子基团苯基,并对其进行全氘代,同时对5-甲基-2-对甲苯基吡啶主配体的两个甲基进行全氘代,分别合成了两种铱磷光配合物Ⅳ和Ⅳ-d₂₀,采用元素分析、质谱和核磁共振氢谱对其结构进行了表征与确认。利用UV-Vis 光谱、荧光发射光谱(PL)和循环伏安法对其光物理性质及能级结构进行了研究。结果表明：铱配合物的Ⅳ和Ⅳ-d₂₀光致发光光谱发射波长分别为546.85nm和548nm;它们的HOMO和LUMO能级分别为-5.237ev和-2.645ev、-5.082ev和-2.50ev,都是潜在的黄绿色磷光材料。以铱配合物Ⅳ和Ⅳ-d₂₀为客体,制备了结构为ITO/HT:NDP-9(100nm,2%)/HT(130nm)/EB(10nm)/GH:化合物Ⅳ或Ⅳ-d₂₀(40nm,5%)/HB(10nm)/ ET:Liq(35nm,50%)/Liq(10nm)/Al(150nm)的OLED器件,并研究了它们的器件性能。结果表明：铱配合物Ⅳ-d₂₀表现出更优异的器件性能。电流密度为20mA/cm₂^时,铱配合物Ⅳ-d₂₀的器件发射波长为552nm,CIE 坐标为 (0.422,0.569),电流效率为 87.00cd/A,外量子效率(EQE)高达23.82%。     

Comparison of ethylene polymerization catalyzed over Cr(VI)/silica and Cr(II)/silica catalysts

Summary Ethylene polymerization and the morphology of produced high density polyethylene (HDPE) catalyzed over. Cr(VI)/silica and Cr(II)/silica were studied. Cr/silica catalyst with Cr loading of 1 wt % has been prepared by impregnating an aqueous solution of CrO₃ onto silica having specific surface area of 301 m²/g and pore volume of 1.64 ml/g. The rate profiles and the morphologies of polyethylene polymerized over Cr(VI) and Cr(II)/silica were different. The process of active site formation influences the rate profiles. The shape of polyethylene particles polymerized with Cr(II)/silica resembled the original shape of catalyst particles. However, Cr(VI)/silica catalyst particles were fractured inhomogeneously during the polymerization. The variation of molecular weight and molecular weight distribution at various polymerization times indicated that the formation of active sites of Cr(VI)/silica was accomplished gradually during polymerization.