Li＋交换的几种分子筛的氮氩分离性能

采用水溶液离子交换法制备了高Li＋交换度的4A、13X和LSX分子筛,并在25 ℃下测定了它们的静态吸附等温线和动态穿透曲线.研究发现,高Li＋离子交换度的4A、13X和LSX分子筛都具有较大的氮吸附容量和较高的氮氩分离选择性,说明高Li＋离子交换度的4A、13X和LSX分子筛是较好的氮氩分离吸附剂.从动态穿透曲线结果来看,所研究的三种分子筛都有一个最优的吸附分离压力,在本文研究的压力范围内,这个最优压力在0.6 MPa附近.对比高锂交换度的三种分子筛,以高锂交换度的LSX分子筛的氮氩吸附分离性能最好.     

增添表面结构化学教学内容的建议

固体物质的体相结构和性质在其表面上有所反映和继承。表面原子排列的图象,理论上可以根据晶体结构加以推断。但是实际上,表面原子往往倾向于进入新的平衡位置,从而使表面层内原子间的距离、配位数、配位多面体的型式以及化学键的性质等发生变化,甚至重建表面结构。因此,不能简单地把表面看作体相的中止,把表面结构看作体相结构的简单延     

Ca2+交换的几种分子筛的氮氩分离性能

采用水溶液离子交换法制备了Ca2+交换的4A,13X和LSX分子筛,并在25 ℃下测定了它们的静态吸附等温线和动态穿透曲线.研究发现, Ca2+交换的4A,13X和LSX分子筛对氮的吸附性能都明显优于其相应的钠型分子筛,而它们对氩的吸附量变化不大,说明Ca2+交换的这三种分子筛是较好的氮氩分离吸附剂.从动态吸附的结果来看,所研究的各种分子筛都有一个最优的吸附分离压力,在本论文研究的压力范围内,这个最优压力在0.6 MPa附近.由穿透曲线可推算出混合气体的吸附量,通过氮和氩在混合气体中的吸附量和相应纯气体吸附量的对比可以得出,对于氮氩吸附选择性较高的分子筛,氮的存在对氩的吸附量有较大的影响.     

复合载体TiO2/SiO2的气相吸附法制备及MoO3在其表面上的分散状态

用气相流动吸附法制备了TiO_2/SiO_2复合载体,用浸渍法制备了MoO_3/(TiO_2/SiO_2)催化剂。应用XRD和LRS等技术研究了TiO_2在SiO_2表面及MoO_3在TiO_2/SiO_2表面上的分散状态。结果表明,TiO_2在复合载体中的含量低于其分散阈值时,它在SiO_2表面呈单层但非密置单层分散;MoO_3在催化剂中的含量低于其分散阈值时,它在复合载体表面亦呈单层但非密置单层分散。TiO_2与SiO_2之间、MoO_3与TiO_2/SiO_2之间相互作用都较弱。TiO_2在SiO_2表面的分散可改善MoO_3的分散状态,提高MoO_3在SiO_2表面上的分散阈值。     

钇离子在氯化物熔盐中的电化学还原

利用循环伏安法、计时电位法和卷积伏安法研究了钇离子在LiCl-KCl熔盐体系中,钼电极上的阴极过程。结果表明,钇离子的电化学还原反应是简单的一步反应,阴极过程在较低扫描速度下接近于可逆过程,且受扩散控制。阴极产物为固态钇。     

PAN基中空纤维炭膜炭化条件的研究

研究了以ＰＡＮ其中空纤维膜为基质制备中空纤维央膜的过程。考察了ＰＡＮ厚膜的预氧化和炭化条件对中空纤维炭膜Ｈ２，Ｎ２气体渗透性和选择性的影响。结果表明，预氧化温度和时间对Ｈ２，Ｎ２气体的渗透速率有一定影响；     

Synthesis of N,N,N-4,4＂-Di-（4-methylphenyl）-2,2＇：6＇,2＂- terpyridine-N,N,N-tris（isothiocyanato） Ruthenium（Ⅱ） and Application to Colorimetric Hg^2＋ Sensor

A terpyridine derivative DPTP [di-（4-methylphenyl）-2,2＇：6＇,2＂-terpyridine] was conveniently synthesized from 2-bromopyridine via halogen-dance reaction, Kharash coupling and Stille coupling reaction. Then its corresponding ruthenium complex Ru-DPTP [N,N,N-4,4＇＇-di-（4-methy,phenyl）-2,2＇：6＇,2＂-terpyridine-N,N,N-tris（is,-thi,cyanat,）- ruthenium（H） ammonium] was obtained and fully characterized by IR, UV-Vis, ESI MS and elemental analysis. The MLCT absorption band of Ru-DPTP was blue-shifted from 570 to 500 nm upon addition of Hg^2＋. Among a series of surveyed metal ions, the complex showed a unique recognition to Hg^2＋, indicating that it can be used as a selective colorimetric sensor for Hg^2＋.     

Study on Properties of TBP-HNO3 Complex Used for Direct Dissolution of Lanthanide and Actinide Oxides in Supercritical Fluid CO2

The tri-n-butyl phosphate-nitric acid （TBP-HNO3） complex prepared by contacting the pure TBP with the concentrated HNO3 can be used for direct dissolution of lanthanide and actinide oxides in the supercritical fluid carbon dioxide （SCF-CO2）. Properties of the TBP-HNO3 complex have been studied. Experimental results showed that when the initial HNO3/TBP volume ratio was varied from 1 ： 7 to 5 ： 1, the concentration of HNO3 in the TBP-HNO3 complex changed from 1.95 to 5.89 mol/L, the [HNO3]/[TBP] ratio of the TBP-HNO3 complex changed from 0.61 to 2.22, and the content of H20 in the TBP-HNO3 complex changed from 2.02% to 4.19%. All of the density, viscosity and surface tension of the TBP-HNO3 complex changed with the concentration of HNO3 in the complex, and were higher than those of the pure TBE The protons of HNO3 and H2O in the complex underwent rapid exchange to exhibit a singlet resonance peak in nuclear magnetic resonance spectra. When the TBP-HNO3 complex was dissolved in a low dielectric constant solvent, small droplets of HNO3 were formed that can be detected by NMR.     

Phase Equilibrium System of CsCl-YCl3-（9.5%）HCL-H2O at T=298.15 K and Its Compounds

Introduction In a series of papers the authors reported the spec-troscopy results on upconversion luminescence of the double salts between the alkali metal (Rb,Cs) halide and rare earth metal trihalide (REX3).1-4 Consequently, ex-tensive syntheses of new double salts and studies on optical properties of such species have received much more attention.5-12 Although a number of these double salts have been synthesized, the formation in alkali metal halide/rare earth metal halide double salts s…     

POSITRONIUM EMISSION FROM SURFACE OF Si SUBSTRATES PASSIVATED BY HF ETCHING

In order to develop a low-temperature heat-treatment technique for the prepa-ration of Si substrates to be used in-situ in molecular beam epitaxy (MBE), surface defects of the HF etched and passivated substrates were investegated with a slow positron beam analysis, the analysis system was equipped on-line with the molecu-lar beam epitaxy device. The fraction of positronium (Ps) emission from Si surface at different temperatures was estimated by a "peak-method", after comparing with the reflection high energy electron diffraction patterns, it was concluded that for a HF treated specimen a clean and stable passivated surface suitable to MBE can be obtained by an in-situ low-temperature (about 550℃) treatment. However, the pa-rameters of HF treatment (etching time, HF concentration, etc.) should be precisely adjusted in order to avoid the production of excessive damages on Si surfaces.