Solid-phase extraction of trace Au(Ⅲ) with SDG and determination by the catalytic spectrophotometric method

The new catalytic kinetic spectrophotometric method for Au(Ⅲ) determination was developed and validated.It was based on the catalytic effect of gold on the oxidation of sudan red Ⅲ by ammonium peroxodisulfate ((NH4)2S2O8) with nitrilo triaeetic acid as an activator in microemulsion and H2SO4 medium.Under optimum conditions,there was the linearity of the calibration curve in the concentration range from 0 to 20 μg/L Au(Ⅲ) at 520 nm.The relative standard deviation was 3.0% with a correlation coefficient of 0.9986.The detection limit achieved was 9.75×10-5 μg/mL.A new method using a column packed with sulfhydryl dextrose gel (SDG) as a solid-phase extraetant has been developed for the preeoncentration and separation of Au(Ⅲ) ions.The method has been applied to the determination of trace gold with satisfactory results.     

Catalytic Spectrophotometry for Vanadium Determination Based on Oxidation of Arsenazo Ⅲ by Bichromate

ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅｄｅｔｅｒｍｉｎａｔｉｏｎｏｆｔｒａｃｅｖａｎａｄｉｕｍｒｅｃｅｉｖｅｄｅｘｔｅｎｓｉｖｅａｔｅｎｔｉｏｎｂｅｃａｕｓｅｏｆｉｔｓｉｎｃｒｅａｓｉｎｇｉｍｐｏｒｔａｎｃｅｉｎｂｉｏｃｈｅｍｉｃａｌａｎｄｅｎｖｉｒｏｎｍ...     

Preconcentrafion/separation and determination of mercury using microcrystalline phenolphthalein modified by ethyl violet

A novel method was developed for enrichment and separation of trace mercury using phenolphthalein modified by ethyl violet (EV).The effects of different parameters,such as stirring time, various metal ions and salts,and the amounts of phenolphthalein, NH4SCN,and EV on the extraction rate of mercury were studied,to select the experimental conditions.Under optimum conditions,mercury can be adsorbed on the surface of microcrystalline phenolphthalein by the intermolecular action strength.The possible reaction mechanism for the enrichment of mercury was discussed in detail.Hg(Ⅱ)could be completely separated from Fe(Ⅱ),Co(Ⅱ),Ni(Ⅱ),Mn(Ⅱ),Cd(Ⅱ),Cr(Ⅲ), and Al(Ⅲ) in the solution.The proposed method has been successfully applied to the determination of trace mercury in industrial wastewater with the recoveries 1.4%,1.1%,and1.2%,respectively.The analytical results were very satisfactory.     

Spectrophotometric Determination of Trace Amounts of Vanadium(Ⅴ) by Means of Its Catalytic Effect on Oxidation of Azomethine-H by Bromate

1ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅｂｉｏｌｏｇｉｃａｌｅｆｆｅｃｔｓｏｆｖａｎａｄｉｕｍｉｎｖｏｌｖｅｎｏｒｍａｌｉｚａｔｉｏｎｏｆｓｕｇａｒｌｅｖｅｌｓ,ｐａｒｔｉｃｕｌａｒｌｙｉｎｖａｒｉｏｕｓｅｎｚｙｍｅｓｙｓｔｅｍｓａｓａｎｉｎｈｉｂｉｔｏｒａｎｄ/ｏｒａｃｏｆａｃｔｏｒ[1].Ｖａｎａｄｉｕｍｉｓａｌｓｏａｎｅｓｓｅｎｔｉａｌｍｉｃｒｏａｍｏｕｎｔｅｌｅｍｅｎｔｆｏｒｈｕｍａｎａｎｄａｎｉｍａｌｓ,ａｎｄｉｔｓｐｒｅｓｅｎｃｅｉｎｔｈｅｒａｎｇｅ20～150ｎｇ/ｍｌｉｎｄｒｉｎｋｉｎｇｗａｔｅｒｈａ…     

铝热自蔓延法制备低氧高钛铁合金及表征

以金红石、钛精矿、Al为原料采用铝热自蔓延法制备出低氧高钛铁。研究相关反应体系的热力学及动力学问题,考察配料比、熔渣类型、发热剂等对铝热自蔓延过程的影响,采用XRD,SEM以及化学分析等技术对高钛铁合金进行表征。结果表明:反应体系的绝热温度大于1800K,反应能自我维持进行;Al还原TiO2反应的表观活化能为93.676kJ.mol-1,反应级数为0.01,Al还原TiO2和Fe2O3的表观活化能为300.740kJ.mol-1,反应级数为1.20;合金主要由TiFe2、TiFe以及Fe2TiO0.13等钛铁低氧固溶体相组成,夹杂相存在是导致合金中氧含量高及微观缺陷存在的直接原因;合金中钛、铝、铁、硅含量分别为:60.0%～62%、7.0%～11.0%、21.0%～25.0%以及3.0%左右;合金中的氧被有效去除,最低为1.85%。     

Tungstophosphoric heteropolyacid supported onto neutral alumina： characterization and synthesis of acetals and ketals

Tungstophosphoric acid （HPW） catalyst supported on the neural alumina was studied. It was prepared by means of an equilibrium and incipient wetness impregnation technique. Solution of HPW in 50% V/V ethanol-water was used to impregnate Al2O3 at 25℃. It was found that the catalyst containing 30% PW by calcination at 500℃ showed a higher catalytic activity in the synthesis of acetals and/or ketals. In the following condition, that is, the molar ratio of aldehyde/ketone to glycol being 1：1.5, the mass fraction of the catalyst used was 0.5%, and the reaction time was 1.0 h; the yields of ketals and acetals could reach up to 60.5%-86.7%. Moreover, it could be easily recovered and reused.     

催化动力学分光光度法测定痕量铕

利用过氧化氢氧化丽春红褪色,以Eu3+为催化剂,建立一种新的测定铕的动力学分光光度法。在6.0×10-2mol/L的盐酸介质中,Eu3+-H2O2-丽春红体系的最大吸收峰位于450nm,Eu3+量在0～22μg/25mL范围内与吸光度差值△A呈良好的线性关系,其回归方程为△A=0.0221C+0.0241(C=μg/25mL),相关系数r=0.9968,方法检出限为2.42μg/L。本方法用于水样中铕的测定,13次测定相对标准偏差为0.49%～1.76%,加标回收率为95.20%～101.3%。     

Catalytic spectrophotometric determination of trace selenium in microemulsion after separation and enrichment by SDG

1. Introduction Selenium is both a micronutrient and toxic ele-ment for living beings, depending on the concentra-tion level. The metal plays an important role in physiological systems including normalization of sugar levels, participation in various enzyme sys-tems as an inhibitor and cofactor and catalyst at the oxidation of various amines. It is also an essential element for cell growth at μg?L?1 levels. However, an excess of selenium in food or pharmaceutical preparations is hazardous to…     

铂钯精矿湿法分离Bi、Fe富集贵金属工艺

以铜阳极泥分铜液还原所得铂钯精矿为原料,根据其矿物特性选择HCl作为浸出剂湿法脱除Bi、Fe等主要贱金属元素,富集Au、Ag、Pt、Pd等贵金属;通过热力学计算绘制Bi(Ⅲ)、Fe(Ⅲ)在盐酸体系的组分分布图,实验考察了HCl浓度、Cl-浓度、反应温度和时间等因素对Bi、Fe浸出率的影响.结果表明:在HCl浓度为2 m...     

用钒(V)-PAR-NH_2OH-DDMAA混合显色体系测定钒

研究了钒(V)-PAR-羟胺-DDMAA(Dodecyldimethylamino acetic acid)混合显色配位体系的特性.该体系在0.5～0.9mol/L硫酸溶液介质中,其最大吸收峰λ_(max)为560nm波长处,在560nm波长处空白值几乎等于零,摩尔吸光系数∈_560为3.7× 10~4L·mol~(-1)·cm~(-1).配合物的组成比,V(v):PAR:NH_2OH:DDMAA为1:1:1:1:1.0～30μgV~(5+)+/25ml范围内.服从比尔定律,用该方法直接测定钨精矿和钨矿中微量钒,获得了满意的结果.     

Catalytic-kinetic spectrophotometric determination of vanadium （V） based on the Celestine blue-bromate-vanadium （V）-citric acid reaction

A novel sensitive and relatively selective kinetic method is presented for the determination of V(V) based on its catalytic effect on the oxidation reaction of Celestine blue by potassium bromate in the presence of citric acid as an activator.The reaction was monitored spectrophotometrically by measuring the decrease in absorbance of Celestine blue at a maximum absorption wavelength of 540 nm between 0.5 and 9 min(the fixed-time method) in an H3PO4 medium at 45°C.The effect of various parameters such as con...     

Preparation of SO2-4/TiO2-WO3 solid superacid and its catalytic activity in acetalation and ketalation

SO2-4/TiO2-WO3 was prepared and its catalytic activity under different synthetic conditions was discussed with esterification of n-butanoic acid and n-butyl alcohol as probing reaction. The optimum conditions are found that the mass fraction of H2WO4 used in the compound is 12.5%, the calcination temperature is 580℃, the calcination time is 3 h, and the soaked consistency of H2SO4 is 1.0 mol.L-1. Then SO2-4 /TiO2-WO3 was applied as the catalyst in the catalytic synthesis of eight similar important ketals and acetals under the optimum conditions and revealed high catalytic activity. On condition that the molar ratio of aldehyde/ketone to glycol is 1:1.5, the mass fraction of the catalyst used in the reactants is 0.5%, and the reaction time is 1.0 h, the yields of ketals and acetals can reach 64.2%-95.1%. Moreover, it can be easily recovered and reused.     

V(Ⅴ)-Fe(Ⅲ)-S(Ⅵ)-H2O系热力学研究与钒铁分离方法理论

针对酸浸液钒铁分离的难题,绘制298 K时V(Ⅴ)-Fe(Ⅲ)-S(Ⅵ)-H2O系中存在的各种离子随pH以及浓度变化的热力学平衡图,全面分析钒、铁物种随pH和钒、铁、硫浓度的变化规律,在此基础上提出相应的钒铁分离方法并进行理论分析。结果表明:强酸条件(?1相似文献   

Mg-Zn-Ca系富Mg侧三元化合物及其300℃固态相平衡

采用合金平衡组织结构分析法,利用扫描电镜组织观察、电子探针定量成分分析以及X射线衍射和透射电子衍射结构分析,对Mg-Zn-Ca系富Mg区域300°C的相平衡关系及平衡相成分进行研究。结果表明：300°C时,2个三元化合物T1和T2都可与Mg基固溶体相平衡。T1相是一个线性化合物相,成分为15%Ca（摩尔分数）,20.5%～48.9%Zn,余量为Mg。T1相为六方晶体结构,晶格常数为：a=0.992～0.945nm,c=1.034～1.003nm,随T1相中Zn含量的增加而减少。化合物T2相也是六方结构,成分为26.4%～28.4%Mg,63.2%～65.5%Zn以及7.1%～8.4%Ca。300°C时,Zn在Mg基固溶体中的溶解度随Ca的加入而增大,最大溶解度达到3.7%。在Mg-Zn-Ca系中300°C等温截面相图的富Mg区域存在着三相区α-Mg＋Mg2Ca＋T1,α-Mg＋T1＋T2,α-Mg＋T2＋MgZn和MgZn＋T2＋Mg2Zn3。     

Removal of vanadium from ammonium molybdate solution by ion exchange

The separation techniques of vanadium and molybdenum were summarized, and a new method of removal V(Ⅴ) from Mo(Ⅵ) by adsorption with chelate resin was presented. Nine kinds of chelate resins were used to investigate the adsorbent capability of V(Ⅴ) in ammonium molybdate solution with static method. The test results show that DDAS, CUW and CW-2 resins can easily adsorb V(Ⅴ) in ammonium molybdate solution, but hardly adsorb Mo(Ⅵ). The dynamic experimental results show more than 99.5% of V(Ⅴ) can be adsorbed, and the adsorption rate of Mo(Ⅵ) is less than 0.27% at 294-296 K for 60 min at pH 7.42-8.02. The mass ratio of V to Mo decreases to l/5 0000 in the effluent from 1/255 in the initial solution. The loaded resin can be desorbed by 5% NH3·H2O solution, and the vanadium desorption rate can reach 99.6%. The max concentration of vanadium in desorbed solution can reach 20 g/L, while the concentration of molybdenum is less than 0.8 g/L.     

Study on Quenching Effect of Holmium (Ⅲ) Ion in Chemiluminescence System of Luminol H_2O_2-Cr(Ⅲ) by Flow Injection Technique

1 ＩｎｔｒｏｄｕｃｔｉｏｎＡｔｐｒｅｓｅｎｔ ,ｔｈｅｒｅａｒｅｍａｎｙｒｅｐｏｒｔｓａｂｏｕｔｔｈｅｄｅｔｅｒｍｉｎａｔｉｏｎｏｆＨｏ(Ⅲ ) [1 ,2 ],ｗｈｉｃｈ ,ｈｏｗｅｖｅｒ ,ｈａｖｅｓｅｌｄｏｍｂｅｅｎｉｎ ｖｏｌｖｅｄｗｉｔｈｃｈｅｍｉｌｕｍｉｎｅｓｃｅｎｃｅ (ＣＬ)ａｎａｌ ｙｓｉｓ .Ｉｎｔｈｉｓｐａｐｅｒ ,ａｎｅｗＣＬａｎａｌｙｔｉｃａｌｍｅｔｈｏｄｆｏｒｔｈｅｄｅｔｅｒｍｉｎａｔｉｏｎｏｆＨｏ(Ⅲ )ｉｏｎｂｙｆｌｏｗｉｎｊｅｃｔｉｏｎｔｅｃｈｎｉｑｕｅｉｓｐｒｅｓｅｎｔ ｅｄ .Ｉｔｉｓｂａ…     

Quantification of trace amounts of impurities in high purity cobalt by high resolution inductively coupled plasma mass spectrometry

An analytical method using high resolution inductively coupled plasma mass spectrometry (HR-ICP-MS) for rapid simultaneous determination of 24 elements (Be, Mg, Al, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Ga, Ge, As, Se, Mo, Ag, Cd, Sn, Sb, Ba, Pt, Au, and Pb) in high purity cobalt was described. Sample digestions were performed in closed microwave vessels using HNO3 and HCl. The matrix effects because of the presence of excess HCl and Co were evaluated. The usefulness of high mass resolution for overcoming some spectral interference was demonstrated. The optimum conditions for the deter- mination were tested and discussed. The standard addition method was employed for quantitative analysis. The detection limits were 0.016-1.50 μg?g?1, the recovery ratios were 92.2%-111.2%, and the RSD was less than 3.6%. The method was accurate, quick, and convenient. It was applied to the determination of trace impurities in high purity cobalt with satisfactory results.     

对碘偶氮氯膦用于微量铂系元素测定的应用研究

根据对碘偶氮氯膦在微量铂系元素Ru、Rh、Os、Ir、Pt等离子的存在下与氧化剂KIO4(KBrO3)之间的褪色反应建立了这5种铂系元素的催化光度分析新方法;而对碘偶氮氯膦在硝酸介质中能与钯形成稳定的蓝色络合物又建立了分光光度法测定微量钯的新方法.作者研究了此系列反应的最佳条件及用于各种铂系元素测定的方法和应用.     

纳米SCR催化剂Ce-V/TiO_2的制备与研究

采用溶胶-凝胶法和浸渍法制备选择性催化还原(SCR)脱硝反应复合纳米催化剂Ce-V/TiO_2,在不同的实验条件下制备出一系列的TiO_2凝胶用作催化剂载体.然后通过浸渍法依次负载CeO_2和V_2O_5于多孔TiO_2载体.用氨气作为还原性气体,对选择性催化还原NOx进行实验研究.在不同的TiO_2载体煅烧温度、CeO_2和V_2O_5负载量以及催化还原反应温度等条件下,对催化剂的表面结构和催化性能采用BET、XRD、SEM等手段进行表征分析.结果表明,纳米Ce-V/TiO_2固溶体复合催化剂以及对其制备工艺技术参数的优化可增大催化剂的比表面积和微孔体积,使催化剂的催化活性有很大的提高.此外,相当数量的多孔纳米TiO_2大大增加了光催化活性的有效面积,有利于增大与反应物的接触面积和提高光催化活性.当载体TiO_2 的煅烧温度和催化还原反应温度为500 ℃时,5%Ce-10%V/TiO_2催化剂反应的NO_x转化率可达96.2%.     

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.