儿茶素在离子交换纤维上的吸附动力学

儿茶素在离子交换纤维上的吸附动力学;离子交换纤维; 儿茶素; 吸附动力学; 反应级数; 反应速率常数     

离子交换法提取谷氨酸的研究

本文就离子交换法提取谷氨酸树脂的筛选，不同树脂对发酵液中谷氨酸静态吸附性能及其影响因素进行了系统地研究．旨在探索离子交换法提取谷氨酸的最佳工艺条件和开发新的离子交换树脂．     

水滑石的插层及其选择性红外吸收性能

离子交换;水滑石的插层及其选择性红外吸收性能     

离子交换法分离乳酸的研究

本文对离子交换法分离乳酸的离子交换树脂、交换相平衡和交换动力学进行了研究,并在离子交换柱上测定了南开大学化工厂生产的201×4树脂的交换曲线。实验结果说明,用离子交换法分离发酵液中乳酸是可行的。     

层状钠锰氧化物的制备及离子交换反应动力学

层状钠锰氧化物的制备及离子交换反应动力学     

碱性氨基酸离子交换平衡特性的研究

研究了碱性氨基酸与001×7阳离子交换树脂的离子交换平衡特性。测定了001×7树脂对碱性氨基酸两种价态离子的选择性吸附系数,并考察了pH和碱性氨基酸的浓度对平衡吸附量的影响,确定了离子交换的最佳pH 和碱性氨基酸的浓度。     

低浓度下离子交换树脂吸附氨基酸的机理

详细地研究了在低浓度下, 酸(碱)式或盐式强酸性阳离子和强碱性阴离子交换树脂吸附氨基酸的机理·结果表明, 氨基酸通过离子交换、离子转移和物理吸附等三种机理被离子交换树脂吸附。     

蛋白质的离子交换平衡及动力学

众所周知,离子交换色层是蛋白质分离的有效方法,而离子交换平衡及动力学是决定分离效果的重要因素。本文介绍了蛋白质在离子交换剂及水溶液之间分配的平衡关系式以及离子交换速度方程。此外,还讨论了实验方法。     

离子交换的专用术语

１９７２年，ＩＵＰＡＣ的ＡｎａｌｙｔｉｃａｌＣｈｅｍｉｓｔｒｙＤｌｖｌｓｌｏｎ，ＣｏｍｍｉｓｓｉｏｎｏｎＡｎａｌｙｔｉｃａｌＮｏｍｅｎｄａｔｕｒｅ（ＰｕｒｅＡｐｐｌ．Ｃｈｅｍ，２７（１９７２）６１９）推荐了离子交换的专用术语。鉴于２０多年来离子交换发展很快，在１９９４年召开的离子交换的命名、公式、定义及实验方法的国际专家讨论会（离子交换与吸附，１０（１９９４）５６３）建议对１９７２年的术语作相应的修订，本文介绍了该讨论会建议的离子交换的专用术语，包括基本定义，离子交换剂，平衡参数，扩散及离子交换色谱等五部分。其中某些术语是ＩＵＰＡＣ，ＡｎａｌｙｔｉｃａｌＣｈｅｍｉｓｔｒｙＤｉｖｉｓｉｏｎ，ＣｏｍｍｉｓｉｏｎｏｎＣｈｒｏｍａｔｏｇｒａｐｈｙａｎｄＯｔｈｅｒＡｎａｌｙｔｉｃａｌＳｅｐａｒａｔｉｏｎ和ＣｏｍｍｉｓｓｉｏｎｏｎＡｎａｌｙｔｉｃａｌＮｏｍｅｎｃｌａｔｕｒｅ在１９９３年推荐的（ＰｕｒｅＡｐｐｌ．Ｃｌｅｍ，６５（１９９３）８１９）。     

我国离子交换膜的生产与应用

本文综述了国内离子交换膜的生产与应用，提出了离子交换膜今后发展的方向。     

Synthesis of LiAlTiO4 and its selectivity to Li+ exchange

The ion-exchanger LiAlTiO₄ of spinel type was prepared by the common precipitation/hydrothermal crystallization method, and was acid-modified. Its ion-exchange properties for alkali ions such as saturation capacity of exchange, distribution coefficient and pH titration curve were determined. LiAlTiO₄ was characterized by the X-ray diffraction method. The acid treatment of LiAlTiO₄ caused Li⁺ extraction ratio to change from 28% to 72%, while the dissolution of Al is less than 6.8%. This inorganic ion-exchanger (LiAlTiO₄-700) has a higher saturation capacity of exchange for Li than for other alkali ions, the saturation capacity of exchange for Li⁺ reaches 4.29 mmol/g (30.03 mg/g); LiAlTiO₄-700(H) has a higher selectivity of ion exchange for Li⁺ than for other alkali ions. These results show LiAlTiO₄-700(H) has better memory and selectivity of ion exchange, and higher capacity of ion exchange for Li⁺. It is a kind of prospective ionic sieve for Li⁺. __________ Translated from Chinese Journal of Applied Chemistry, 2005, 22 (7) (in Chinese)     

Li4Mn0.5Ti0.5O4合成与鉴定

Li4Mn0.5Ti0.5O4合成与鉴定;LiMnTi复合氧化物;尖晶石型结构;离子筛;离子交换;锂     

LiMg0.5Mn1.5O4的合成及对Li+的离子交换选择性

锂及其化合物在航空航天、化工、医药、空调、高能电池和热核反应等方面都有广泛应用，对锂及其化合物的需求与日俱增。我国液体锂资源非常丰富，开发利用其中的锂资源具有重要意义。从盐湖水、地下卤水、盐田母液、油气田水等咸水资源中提取锂的方法有碳酸盐沉淀法、离子交换法、萃取法等。离子     

Preparation and evaluation of composite ion-exchanger for the removal of cesium and strontium radioisotopes

Preparation conditions of composite ion-exchanger based on stannic molybdophosphate (SMP) and poly-acrylamide (PAA) have been described. Batch distribution coefficients for some ions were investigated at 25 °C. Sodium ion exchange capacity and breakthrough curves of cesium and strontium ions have also been determined. The results obtained from the experiments showed that the selectivity of SMP-PAA for cesium and strontium was greater than for other ions. Adsorption amounts of both ions were higher than 99% in demineralized water and their uptake rate were relatively rapid.     

合成钾型丝光沸石的酸改型及对K+的离子交换性

合成出钾型丝光沸石,对其进行了酸改型,测定了其对碱金属离子的饱和交换容量和分配系数、ｐＨ滴定曲线等离子交换性能,并对该沸石进行了Ｘ射红衍射分析和ＦＴ－ＩＲ分析。结果表明,该沸石对钾离子具有较强的交换选择性。     

阳离子交换色谱中色谱柱温度对碱金属与碱土金属离子保留的影响

研究了非抑制型阳离子交换色谱中色谱柱温度(25~50℃)对碱金属离子(Li+、Na+、K+、Rb+)和碱土金属离子(Mg2+、Ca2+、Sr2+)以及NH4+保留的影响。在Shim-pack IC-C1磺酸型阳离子交换柱上,以硝酸为流动相分离碱金属离子,以乙二胺或乙二胺-草酸(柠檬酸)为流动相分离碱土金属离子,随着色谱柱温度的升高,碱金属和碱土金属离子的保留时间均增长,其范特霍夫曲线具有良好的线性关系,斜率为负值,表明在此条件下碱金属和碱土金属离子的保留为吸热过程。在Shim-pack IC-SC1羧酸型阳离子交换柱上,以硫酸为流动相同时分离碱金属和碱土金属离子,随着色谱柱温度的升高,Mg2+、Ca2+的保留时间增长,而K+、Rb+的保留时间缩短,Li+、Na+、NH4+的保留时间基本不变。在此条件下,Mg2+、Ca2+、K+和Rb+的范特霍夫曲线具有良好的线性关系,其中Mg2+和Ca2+的曲线斜率为负值,K+和Rb+的曲线斜率为正值,表明Mg2+和Ca2+的保留表现为吸热过程,K+和Rb+的保留表现为放热过程。研究表明在不同固定相和流动相条件下,色谱柱温度对碱金属和碱土金属离子保留行为的影响不同。     

Calculation on ion exchange capacity for an ion exchanger using the potentiometric titration

We calculated the characteristics of a phosphoric cation exchanger and studied an accurately computable method for ion exchange capacity for a type of potentiometric titration curve. The ion exchanger was prepared by phosphorylation of a styrene‐divinylbenzene copolymer. The ion exchange capacity was 5.7 meq/g. The experimental pK values versus χ in a phosphoric cation exchanger can explain a linear equation. The ΔpK values were obtained from the slope of a linear equation. The ΔpK values were the differences of pK values between the apparent equilibrium constant at complete and zeroth neutralization of the ion exchanger. The experimental pK values at χ = 0.5 (χ:degree of neutralization of ion exchanger) showed good agreement with the theoretical data. When it was titrated with NaOH and Ba(OH)₂ solutions, a good agreement between experimental and theoretical pK values for various χ was found in all potentiometric titration curves. The potentiometric titration curve near the inflection point in the case of divalent ions was changed more sharply than that for monovalent ions. The plot of ∂pH/∂g versus g (number of moles of alkali to 1 g of ion exchanger) was fitted to the Lorenzian distribution, from which ion exchange capacity was accurately evaluated. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 3181–3188, 2000     

Separation of europium, cobalt and zinc on zirconium tungstate ion exchanger

Summary Amorphous zirconium tungstate inorganic ion-exchanger has been prepared under optimum conditions and characterized by IR, X-ray and thermal analysis. Surface area and capacity are determined. It has characteristic IR absorption peaks at 3242, 1628, 955, 868 and 432 cm^-1 and is thermally stable up to 450 °C. Its surface area was 16 m²/g with an exchange capacity of 0.541 meq/g. The sorption of radioactive europium from different media at ambient temperature by the zirconium tungstate (ZW) exchanger has been studied. The aim was to optimize the conditions for sorbing Eu from radioactive waste and cleaned the ZW from for recycling. The effect of contact time, metal concentration, pH and temperature has been measured. Percentual uptake of Eu(III) reaches 95% for HCl at pH 4 and increases with temperature indicating an endothermic sorption process. Uptake of Zn(II) and Co(II) on ZW from acetic acid was found to be 42% and 24% for cobalt and zinc, respectively. Desorption after saturation and the effect of other radioactive ions on the percentual uptake of Eu on ZW were investigated. A solution of 3M HCl releases 90%, 25% and 13% of the loaded Eu(III), Co(II) and Zn(II), respectively.     

Preparation, Properties and Mechanism of Inhomogeneous Calcium Alginate Ion Cross-linking Gel Microspheres

Inhomogeneous calcium alginate ion cross-linking gel microspheres,a novel ion absorbent,were prepared by dropping a sodium alginate solution to a calcium chloride solutioin via an electronic droplet generator.Calcium alginate microspheres have uniform particle sizes.a smooth surface and a microporous structure.The electrode probe reveals the inhomogeneous distribution of calcium ions with the highest concentration on the surface,and the lowest concentration in the cores of the spheres.As a novel ion adsorbent,calcium alginate gel microspheres have a lower limiting adsorption mass concentration,a higher enrichment capacity and a higher adsorption capacity for Pb^2 than usual ion exchange resins.The highest percentage of the adsorption is 99.79%.The limiting adsorption mass concentration is 0.0426mg/L.The adsorption capacity for Pb^2 is 644mg/g,Calcium alginate gel microspheres have a much faster ion exchange velocity than D418 chelating resin and D113 polyacrylate resin.The moving boundary model was employed to interpret the ion exchange kinetics process,which indicates that the ion exchange process is controlled by intraparticle diffusion of adsorbable ions.So the formation of inhomogeneous gel microspheres reduces the diffusion distance of adsorbable ions within the spheres and enhances the ion exchange velocity.Alginate has a higher selectivity for pb^2 than for Ca^2 and the selectivity coefficient KCa^Pb is 316. As an ion cross-linking gel,calcium alginate inhomogeneous microspheres can effectively adsorb heavy metal Pb^2 at a higher selectivity and a higher adsorption velocity.It is a novel and good ion adsorbent.     

固态法制备含钼组分碱金属离子Y分子筛性质的比较

利用固态离子交换法制备含钼组分碱金属离子Y分子筛 ,红外光谱和X射线衍射表明碱金属离子的交换度随离子半径增大而变小。含钼组分分子筛催化剂显现出很高的合成醇选择性 ,且随碱金属离子碱性增加 ,高碳醇比例增加。