高岭土原位晶化产品及全合成Y型沸石的稀土离子的交换平衡

本文测定了钠式高岭土原位晶化产品及全合成Ｙ型沸石与稀土离子铽Ｔｂ（Ⅲ）的离子交换等温线和平衡数据，采用了三种不同的热力学方法处理平衡数据，求得该离子交换反应Ｎｄ→Ｔｂ的选择系数、修正选择系数、热力学平衡常数以及标准自由能、热焓、熵的改变量。对这种离子交换剂的结果及三种热力学处理方法进行了对比及讨论。     

Y型沸石和高岭土原位晶化产品的Tb／Tb同位素交换及Na／Tb、Tb／Na离子交换动力学

本文在前文［１］Ｙ型沸石和高岭土原位晶化产品上的Ｎａ／Ｔｂ离子交换平衡研究的基础上，进一步研究了这两种离子交换剂上Ｔｂ／Ｔｂ同位素交换及Ｎａ／Ｔｂ、Ｔｂ／Ｎａ正逆离子交换动力学，确定了反应机理，测得了铽的自扩散系数以及正道交换的积分粒内互扩散系数。对这两种离子交换剂所得结果进行了对比和讨论。     

Y型沸石和高岭土原位晶化产品的Tb／Tb同位素交换及NaTb,Tb／…

本文在前文＾［１］Ｙ型沸石和高岭土原位晶化产品上的Ｎａ／Ｔｂ离了交换平衡研究的基础上，进一步了这两种离了交换剂上Ｔｂ／Ｔｂ同位素交换及Ｎａ／Ｔｂ，Ｔｂ／Ｎａ正逆离子交换动力学，确定了反应机理，测得了铽的自扩散系数以及正逆交换的积分粒内互扩散系数。对这两种离交换剂所得结果进行了对比和讨论。     

Y型沸石上Na→Tb不完全离子交换反应的三种热力学处理

本文将四种不同硅铝比Y型沸石在303及333K的Na→Tb离子交换的平衡数据,按三种固相标准状态及参考状态不同的热力学处理方法处理,分析比较了处理结果,讨论了三种方法的优缺点。     

《离子交换平衡及动力学》一书出版发行

由兰州大学陶祖贻教授等人编著的《离子交换平衡及动力学》一书作为高等学校的试用教材,最近由原子能出版社出版发行。离子交换反应的理论主要包括研究交换平衡的热力学和研究交换反应速度的动力学。应该说,描述离子交换平衡的最合适也是最严格的方法是热力学,目前,离子交换反应的热力学研究已经取得了很大成绩,已经从二元离子交换体系发展到三元及多元体系,从     

二元及三元离子交换体系的统计热力学

本文用统计热力学方法对二元及三元离子交换体系进行了研究,得到了修正选择系数与交换剂组成关系的理论表达式,并得到二元交换体系的交换剂组分活度系数与组成的关系式,即Kielland公式。     

CuSO4—氨化P507—n—C6H14体系平衡常数的计算

用热力学方法研究了酸性磷取剂与金属体系间的平衡计算模型，萃取体系的水相采用Ｐｉｔｚｅｒ半经验公式求算γＣｕ＾２＋，有机相用热力学关系求出了水，正己烷和萃取剂的活度系数，实验结果用Ｓｃｈａｔｃｈａｒｄ－Ｈｉｌｄｅｂｒａｎｄ模型关系，并经回归处理，得到了萃取反应热力学平衡常数及萃合物的活度系数。     

钠型斜发沸石Na^＋—K^＋离子交换特性研究（Ⅰ）—离子交换过程热力学特性

测定出斜发沸石的阳离子交换容量为192．18mmol／100g沸石：通过10℃、25℃、50℃、75℃钠型斜发沸石Na^ —K^ 离子交换等温线、温度对选择性校正系数的影响及Kiclland图研究表明：钠型斜发沸石对钠钾混合体系中的钾具有很高的选择性，且随着温度的上升，沸石对钾的选择性下降，并回归出Langmuir模型：依据热力学平衡原理，导出了钠型斜发沸石Na^ —K^ 离子交换过程平衡常数表达式，并计算出该过程的焓、吉布斯自由能和熵变化，进一步验证该过程可自发进行，且为放热反应，低温有利于钾离子吸附。     

离子交换法分离乳酸

本文在对多种吸附剂和离子交换树脂进行筛选的基础上，获得了一种对乳酸具有优良吸附性能的弱碱型离子交换树脂，测定了乳酸在该树脂上的离子交换平衡数据，建立了数学模型，研究了其它无机盐的存在对离子交换平衡的影响，同时测量了乳酸在该树脂上的交换速率和穿透曲线．上述研究对于乳酸分离，特别是从稀溶液中分离乳酸提供了一种新的方法，对其它有机酸的分离也具有参考意义．     

磷酸可待因在安伯来特IRP-69上的离子交换平衡特性研究

采用批式离子交换法研究了磷酸可待因在安伯来特IRP-69上的离子交换平衡特性、动力学及热力学特征.结果表明,在3个温度(298K、308K和318K)及研究的浓度范围内,离子交换吸附等温方程和Freundlich方程都能够对磷酸可待因在安伯来特IRP-69上的离子交换平衡等温线进行很好的拟合,其离子交换动力学特征基本符合二级动力学方程.磷酸可待因在安伯来特IRP-69上的离子交换行为的热力学参数(ΔH、ΔG、ΔS)都小于0.在3个温度(298K、308K和318K)下,同一初始浓度(350mmol/L)的磷酸可待因在安伯来特IRP-69上的平衡交换吸附量分别为1.1295mmol/g、1.1203 mmol/g和1.1129 mmol/g.     

Zeolite micromembranes

Free-standing silicalite-1 (Sil-1) zeolite micromembranes have been successfully fabricated onto silicon substrate. Gas permeation test using permanent gases (i.e., helium, hydrogen, argon and nitrogen) and hydrocarbons (i.e., methane and n-butane) indicates that the micromembranes have excellent permeance flux and high permselectivity.     

Mazzite型沸石分子筛

Mazzite型沸石具有相对较大的孔道,显示出较强酸性以及较好的热和水热稳定性,在加氢异构化催化剂等领域显示出好的应用前景.本文对Mazzite型沸石子分子筛在结构、合成、酸性和应用方面的研究进行了介绍.     

Zeolite LTA Nanoparticles Prepared by Laser-Induced Fracture of Zeolite Microcrystals

Zeolite LTA nanoparticles are prepared by laser-induced fragmentation of zeolite LTA microparticles using a pulsed laser. Zeolite nanoparticle formation is attributed to absorption of the laser at impurities or defects within the zeolite microcrystal generating thermoelastic stress that mechanically fractures the microparticle into smaller nanoparticle fragments. Experimentally, it is found that nanoparticles have a wide size and morphology distribution. Large nanoparticles (>200 nm) are typically irregularly shaped crystals of zeolite LTA, whereas small nanoparticles (<50 nm) tend to be spherical, dense, and amorphous, indicative of destruction of the original LTA crystal structure. Results of the fragmentation versus laser parameters show that shorter laser wavelengths are more efficient at producing zeolite nanoparticles, which is explained based on a larger cross section for optical absorption in the zeolite crystal. Increasing the laser energy density irradiating the sample was found to be a trade-off between increasing the amount of fragmentation and increasing the amount of structural damage to the zeolite crystal. It is suggested that in the presence of strongly absorbing defects, plasma formation is induced resulting in dramatically higher temperatures. On the basis of these results it is suggested the optimal laser processing conditions are 355 nm and 10 mJ/pulse laser energy for our LTA samples.     

Synthesis of Zeolite ZSM-2 Using Zeolite NaX as Seeds

Introduction Oxygen and nitrogen have been produced tradition-ally by cryogenic distillation of air. Methods for the non-cryogenic separation based on selective adsorption have been developed and commercialized since the 1970s and have led to a cost-effective process for this important separation.1 Low-silica zeolites are important materials for producing oxygen by selective adsorption of nitrogen. In 19891990, a new generation of lith-ium-based adsorbents was developed.2,3 Highly lithium exc…     

Zeolite inclusion complexes

Zeolites provide the largest and most useful family of porous host crystals, stable in the presence or absence of guest molecules. An account is given of their structural characteristics in terms of intracrystalline channels and cavities of molecular dimensions; their total intracrystalline pore volumes; and the intracrystalline distribution patterns of guest molecules, often present as clusters or filaments. The way in which the shape and size of the molecules relate to the shape and size of the apertures or windows giving access to the cavities, together with other factors such as cation location, then determine molecule sieving behaviour, which is discussed with reference to several types of zeolite sieve. The relation between diffusivity and molecular dimensions is also illustrated. A comparison between zeolites and clathrate host lattices shows that there are strong similarities of several kinds. Zeolites may form inclusion complexes with metals, salts and polar or non-polar molecules, examples of which are briefly considered, together with isotherms for some of these types of complex. An account of equilibrium and its formulation demonstrates the thermodynamic background and illustrates the degree of success which has been obtained in describing isotherms in terms of various models.     

介孔沸石材料

介孔沸石材料是含有丰富介孔的结晶沸石,不仅保留了沸石材料优良的酸性和水热稳定性,而且由于介孔的引入改善了其对大分子的吸附和扩散性能,在催化领域特别是涉及大分子的催化反应中是极有应用前景的材料。本文综述了介孔沸石材料的制备方法并进行了比较分析,概述了近年来介孔沸石材料在不同催化反应中的应用,探讨了介孔沸石材料今后的研究方向。     

MFI沸石纳米片及b轴取向MFI沸石薄膜的制备

我们通过自下而上（bottom-up）的方法制备了高宽深比、高结晶度的b轴方向上超薄的MFI沸石纳米片,为制备b轴取向MFI沸石薄膜提供了基础。采用滑动涂覆法（slip coating method）在玻璃片载体上制备了厚度约为100 nm的b轴取向MFI纳米片晶种层。采用无模板剂二次生长法,抑制晶种层面外孪晶生长,实现了晶种层的面内外延生长。在合成体系的n_SiO2：n_Na2O：n_{C2 H5 OH}：n_{H2 O}=1：0.03：1.3：0.89、晶化时间48 h、晶化温度180℃时,制备了厚度约为200 nm的连续致密的b轴取向MFI沸石膜,与基于四丙基氢氧化铵（TPAOH）的常规合成溶液水热二次生长制备的MFI沸石膜相比,厚度降低了90%,并且保持了晶种层的b轴取向性。     

Y沸石水热转晶为ECR-1沸石的研究

ECR-1具有十二元孔道, 其通常是在有机模板存在下合成的, 我们曾报道了在无有机模板剂的条件下合成沸石ECR-1, 本文报道在无有机模板剂存在的条件下Y沸石水热转晶为沸石ECR-1的研究结果. 因为Y沸石具有合成简单、价格低廉和不使用有机模板等特点, 所以对由Y沸石转晶为ECR-1的研究, 对其在工业上的应用具有重要意义.     

Preparation of Zeolite X Membranes on Porous Ceramic Substrates with Zeolite Seeds

Zeolite X membranes were investigated by in-situ hydrothermal synthesis on porous ceramic tubes precoated with zeolite X seeds or precursor amorphous aluminosilicate, and porous α-Al2O3 ceramic tubes with a pore size of 50-200 nm were employed as supports. Zeolite X crystals were synthesized by the classic method and mixed into deionized water as a slurry with a concentration of 0.2-0.5wt%, having a range of crystal sizes from 0.2 to 2μm. Crystal seeds were pressed into the pores near the inner surface of the ceramic tubes, and crystallization took place at 95℃ for 24-96 h. It was also investigated that Boehmite sol added with zeolite X seeds was precoated on ceramic supports to form a layer of r-Al2O3 by heating, and hydrothermal crystallization could then take place to prepare the zeolite membranes on the composite ceramic tubes. The crystal species were characterized by XRD, and the morphology of the supports subjected to crystallization was characterized by SEM. The composite zeolite membranes hav