FRACTIONATION OF LITHIUM ISOTOPES IN ION EXCHANGE CHROMATOGRAPHY WITH TITANIUM PHOSPHATE EXCHANGER

ABSTRACT

Ion exchange chromatography of lithium was carried out to study the lithium isotope effect in an aqueous ion-exchange system, using titanium phosphate exchangers granulated with polyvinyl chloride or an inorganic binder. The sample granulated with PVC showed significant isotope fractionations when a 0.05 M (NH₄)₂CO₃ solution was used as an eluent. The lighter isotope ⁶Li was preferentially fractionated into the exchanger phase. The isotope separation factor was roughly evaluated as 1.007, which is smaller than that (1.017) obtained by batch experiment in a preceding paper. The smaller separation factor could be explained by the fact that the number of sites effective for Li⁺ exchange is less than the number evaluated from the ion exchange capacity. The exchanger granulated with an inorganic binder did not show lithium isotope fractionation in spite of its large capacity for retention of lithium.     

TEMPERATURE EFFECT ON ION EXCHANGE SORPTION OF PHOSPHATE

Phosphate sorption on the strong basic anion exchanger Amberlite IRA-400 (Cl^? form) is studied as a function of temperature ( 25^°C–50^°C), at two initial pH values (5 and 9 ) in the concentration range 120–190 ppm. Chloride released/phosphate sorbed ratios increase with the increase both in temperature and pH and decrease with the increase in the concentration of solution. It is suggested that phosphate sorption takes place initially as HPO₄ ^2? followed by H₂PO₄ ^?. The data is explained with the help of a modified Langmuir and mass law action equations. Various thermodynamic parameters (ΔG^°,ΔH^° and ΔS^°) are presented. The differential isosteric heat of adsorption, is computed at different temperatures, showing the sorption of phosphate to be endothermic on the anion exchanger Amberlite IRA-400.     

SYNTHETIC INORGANIC ION EXCHANGE MATERIALS. XLIII. ION EXCHANGE MECHANISM OF LITHIUM IONS ON CUBIC TANTALIC ACID

ABSTRACT

Ion exchange reaction of lithium ions on cubic tantalic acid (C-TaA) was studied on the basis of pH titration curve for Li+ at 30, 45 and 60°C. The selectivity coefficients were plotted against equivalent fraction of lithium ions in the exchanger at a given temperature, which refers to the Kielland plot The selectivity coefficient on C-TaA was independent of the equivalent fraction of lithium ions in the exchanger up to a certain point and then decreased rapidly due to a phase transition. The results indicate that the reaction was preceded by an ion exchange mechanism for early stage and then phase transition to the hexagonal system.     

磷酸盐玻璃中Tb^3＋离子的敏化发光与能量传递

研究了磷酸盐玻璃中Ｔｂ＾＋离子的敏化发光。结果表明；磷酸盐玻璃中Ｄｙ＾３＋，Ｃｅ＾３＋和Ｔｂ＾３＋产生敏化发光。确立了双掺Ｔｂ＾３＋和Ｄｙ＾３＋玻璃中Ｄｙ＾３＋－Ｔｂ＾３＋敏发化光的声子支助共振能量转移模型，双掺Ｔｂ＾３＋和Ｃｅ＾３＋玻璃中Ｃｅ＾３＋的激光发能通过无辐射能量共振转移每化发光，计算出Ｃｅ＾３＝－Ｔｂ＾３＋的有量传递效率，为确定最佳稀土离子掺加量提供了依据。     

离子交换树脂对有机废水中铜离子的吸附

选用多种大孔强酸型离子交换树脂,用于吸附浓集含有机物废水中的铜离子,通过测定各种树脂对铜离子的去除率、不同铜离子浓度和溶液pH值对去除率的影响,以及各树脂再生性能的比较,表明“争光”、“强酸1号”和PK208树脂性能最为突出,效果明显优于其它几种树脂,可用于吸附处理有机废水中的铜离子。     

THE REMOVAL OF STRONTIUM AND CESIUM FROM SIMULATED HANFORD GROUNDWATER USING INORGANIC ION EXCHANGE MATERIALS

ABSTRACT

A number of inorganic ion exchange materials that are commercially available or under development were evaluated for the removal of strontium and cesium from a simulated groundwater found in the Hanford waste storage area using a groundwater simulant spiked with either 89Sr or 137 Cs. The most promising materials for strontium were found to be a sodium titanosilicate from Texas A&M University closely followed by two titanium silicate pharmacosiderites obtained from AlliedSignal. The most promising materials for the selective removal of cesium from the simulant was again the sodium titanosilicate followed by an alumina-pillared montmorillonite clay obtained from Laporte Industries Ltd. The ion exchange kinetics were shown to be very rapid for both the titanosilicate and the pharmacosiderite, whilst the alumina-pillared montmorillonite had slower kinetics more comparable to those of the zeolite AW500.     

循环水中总无机磷测定方法的改进

对钼兰比色法测定循环水中总无机磷酸盐的方法进行了改进。原钼兰比色法测定循环水中总无机磷的还原剂采用对人体有害的硫酸肼,改用抗坏血酸作还原剂,结果准确度高,偏差小,加标回收率在96．38％～98．64％。     

溶解和离子交换反应中K+的快速测定

离子溶液中快速传递及反应动力学过程的跟踪研究在实验上较为困难 ,为此基于离子选择性电极建立溶液中离子活度即时采集系统 ,并结合活度系数模型准确计算离子浓度 .该方法测定速度快 ,最小间隔为 1s,且所得离子浓度最大偏差小于 2 % .用此方法测定了硫酸钾溶解过程以及钛酸钾离子交换反应过程中钾离子浓度的变化 ,获得传统方法难以测定的数分钟内相关动态过程受溶剂、pH值的影响结果 .该方法可推广应用于研究其他各种动态过程 (如溶解、结晶、沉淀、离子交换、吸附和扩散等过程 )     

SYNTHESIS AND ION EXCHANGE PROPERTIES OF NOVEL INORGANIC ADSORBENTS TINaV)-NITRILOTRIS(METHYLENE)TRIPHOSPHONATES

ABSTRACT

Several new tin(IV) nitrilotris(methylene)triphosphonates of different composition have been synthesized by the reaction of a tin tetrachloride and nitrilotris(methylene)triphosphonic acid [N(CH₂PO(O)OH)₃] and a gel method of their preparation in granular form (as spherical beads) was developed. The solids were characterized by elemental analysis, TGA, FT-IR, MAS ³¹PNMR and X-ray spectroscopy. The ion exchange behavior of tin(IV) nitrilotris(methylene)triphosphonates towards alkali, alkaline earth and some transition metal ions in individual and complex solutions were studied. It was found that these exchangers contain highly acidic adsorption sites, which enables them to operate efficiently even at pH close to 0, High affinity of the tin(IV) nitrilotris(rnethylene)triphosphonates for lead, cadmium, copper in acid solutions makes them promising for treatment of some technological solutions and waste.     

NH4+型斜发沸石对Cu2+的离子交换平衡特征

研究了NH4 型斜发沸石对Cu2 的离子交换平衡特征,计算了不同条件下达到离子交换平衡时,NH4 型斜发沸石对Cu2 的选择性校正系数Kc和交换平衡常数Ka,得出了lnKa与实验温度倒数1/T之间的线性关系,并绘制了离子交换等温线.在此基础上,导出了反应标准摩尔焓变(Δr Hmθ)、反应标准摩尔Gibbs自由能变(Δr Hmθ)和反应标准摩尔熵变(Δr Smθ).结果表明:达到离子交换平衡时,NH4 型斜发沸石对Cu2 的最大交换度仅为0.703,Δr Hmθ为7.101 kJ/mol,Δr Gmθ＜0,Δr Smθ＞0,即该过程是吸热和熵增加反应,且该反应在20 ℃能自动发生,但升高温度有利于NH4 型斜发沸石交换Cu2 .     

制备型离子交换填料综合评估指标体系的构建

填料评估指标体系的构建是填料综合评估的前提。根据生化分离中对填料的要求,本文将离子交换填料的评估指标分成两方面：即稳定性能与操作性能,其中稳定性为达成性指标,操作性为评优指标。后者可以用产率来概括,由３个因素构成,即动态吸附容量、得率和循环时间。得率可通过回收率和分离度来反映,循环时间可通过流速与再生系数反映。上述结构组成离子交换填料评估指标体系。文献统计及实验数据分析证实了指标集构建的合理性。     

交变电场下离子交换色谱分离过程

以牛血清白蛋白在阴离子交换剂DEAE -SepharoseFastFlow上的吸附和解吸过程为例 ,考察了交变电场下离子交换色谱过程的吸附和洗脱过程及其传质特性 .结果表明 :在本文实验条件下 ,交变电场电流强度的变化对离子交换吸附平衡无显著影响 ,而外加电场在介质孔内所产生的电渗流可加速待分离组分进出固相介质的传递过程 ,显著提高色谱填充床的动态吸附容量 ,改善洗脱峰的特性     

THERMODYNAMICS OF ALKALI AND ALKALINE EARTH METAL ION - EXCHANGE ON CERIUM(IV) HYDROGEN PHOSPHATE

ABSTRACT

Thermodynamics of alkali and alkaline earth metal ions/hydrogen ions exchange on a fibrous cerium(IV) hydrogen phosphate have been investigated. Selectivities for alkali and alkaline earth metal ions increase in the order; Na⁺<<K⁺<Rb⁺<Cs⁺ and Mg²⁺<Ca²⁺<Sr²⁺<Ba²⁺, respectively. The enthalpy changes for alkali metal and Ba2+ ions/H⁺ exchange are negative, those for the other alkaline earth metal ions/H⁺ exchange are positive, indicating that the enthalpy changes for monovalent ions are more favorable than those for divalent ions. In comparison with ions of the same valency, the enthalpy change decreases with the atomic number of the metal ion corresponding to a decrease in the entropy change of dehydration in response to enthalpy-entropy compensation.     

漏钠对除盐离子交换的影响及防止

“漏Ｎａ”将导致一级除协水电导率升高和影响阴床出水中ＨＳｉＯ３含量的升高。本文讨论了“漏Ｎａ”产生的原因和防止方法。     

SHELL-PROGRESSIVE MODEL WITH CHANGING BULK CONCENTRATION AND EXCHANGER VOLUME IN ION EXCHANGE

A mathematical model of the shell progressive mechanism with changing bulk solution concentration and exchanger volume in ion exchange is presented and its conformity with experimental results is demonstrated.     

二氧化硅对循环水中无机磷测定的影响及消除方法

考察工业循环水中高含量二氧化硅对无机磷测定结果的影响，找出消除二氧化硅干扰的良好方法，保证无机磷分析的准确性。     

EFFECTIVE DIFFUSION COEFFICIENTS OF COPPER IN MACROPOROUS CHELATING ION EXCHANGE RESIN D751

Kinetic data on the macroporous chelating ion exchange resin D751 containing iminodiacetic acid as ligand are presented. The experimental systems are R-Na / Cu(N0₃)₂, R₂Cu/HNO₃and R-(Na+H) / Cu(NO₃)₂. Sorption and desorption rates of copper were measured in batch experiments by using a three-necked flask as the reaction vessel. The effective diffusion coefficients of copper have been calculated.     

纯水在电泳涂装中的应用和离子交换制取法

介绍了纯水在阴极电泳涂装中的用途、对纯水水质的要求和离子交换制取法的原理、影响因素和操作建议.