硅酸钠与有机硅氧烷前驱体合成有机官能化硅基介孔材料

采用有机硅氧烷（RTES）与硅酸钠（Na2SiO3)共水解缩聚合成有机官能化的 MSU型硅基介孔材料，当前驱体中RTES和硅酸钠的摩尔比为0.1:0.9时合成了R－ MSU（R＝甲基，氨基）分子筛，通过现代分析技术证明有机官能团均进入材料骨架 。选用CH3－MSU合成体系，考察了合成温度、前驱体与模板剂摩尔比及前驱体中有 机硅氧烷含量等反应参数对材料织构性能的影响，发现通过简单地调节反应参数， 能较好地控制材料的结构和表面特性。     

Ethanol Washing Effect on Textural Properties of the Sodium Silicate-Derived Silica Xerogel

This study deals with the use of ethanol as washing solvent in the preparation of the silica gels from sodium silicate in order to enhance the textural properties, especially surface area. We here examined the effect of ethanol-washing on surface area, micro- and mesopore volume, and average pore size. The silica xerogels prepared from sodium silicate solution exhibited an extremely high surface area of 1139 m2/g by washing their hydrogels with ethanol. Compared to water-washed xerogels, ethanol-washed xerogels showed higher surface areas, total pore volumes, and larger average pore sizes. Unlike the surface area of water-washed xerogel, that of the ethanol-washed xerogel was not affected by the silica concentration of initial solution. This study indicates that the textural properties of sodium silicate-derived xerogels are further enhanced by using ethanol as washing solvent.     

Differential Scanning Calorimetry at Hydrothermal Conditions of Amorphous Materials Prepared by Drying Sodium Silicate Solutions

Concentrated sodium silicate solutions with a molar SiO₂:Na₂O ratio of 3.3 and a SiO₂ content of 27 mass% were dried up to 63 d at temperatures between 40 and 100°C to residual water contents between 12 and 38 mass%. The dried solid materials were investigated by differential scanning calorimetry (DSC). Pressure tight autoclave crucibles were applied to suppress evaporation and boiling of the samples during heating. Two thermal events are discussed with respect to glass transition. This revised version was published online in August 2006 with corrections to the Cover Date.     

Composite Silica Particles Using a Mixture of Organosilane Monomers

Composite silica particles were synthesized by a two-step (acid-base) process in an aqueous solution with a mixture of organoalkoxysilane monomers. The two-step process separates the hydrolysis and condensation procedures to easily control condensation rate. In this study, the silane monomers used were phenyltrimethoxysilane (PTMS), vinyltrimethoxysilane (VTMS), methyltrimethoxysilane (MTMS), and tetraethyl-orthosilicate (TEOS). The physical properties of the resultant composite particles were investigated with the change in the molar ratio of monomers. The size of the particles increased with increasing the molar ratio of R_aSi(OR)₃/R_bSi(OR)₃ or R_aSi(OR)₃/TEOS (R_a: phenyl; R_b: vinyl, methyl).     

利用廉价硅酸盐为硅源合成介孔SiO2球

利用廉价的硅酸盐为二氧化硅前驱体,以非离子和阳离子表面活性剂为混合模板剂合成微米级的介孔二氧化硅。控制非离子和阳离子表面活性剂的量可以得到分散性较好的介孔二氧化硅球,其平均颗粒直径为2．5μm,平均孔径为3．25nm,比表面为1379m^2／g,孔体积高达1．12cm^3／g。实验讨论了两种表面活性剂的比例对介孔二氧化硅形貌和介相结构的影响,并用混合模板机理解释了不同形貌形成的原因。     

Growth Mechanism of Large Monodispersed Silica Particles Prepared from Tetraethoxysilane in the Presence of Sodium Dodecyl Sulfate

Monodispersed silica particles up to ca. 1.2 μm in diameter were prepared by hydrolysis of tetraethoxysilane in the presence of sodium dodecyl sulfate (SDS). The particle size was increased with an increase of SDS added. The geometrical standard deviation of the particles was decreased with an increase of SDS. In the earlier reaction stage, double spherical particles by the coalescence of the particles were frequently observed when large amounts of SDS were added. Particle size was gradually increased after the coalescence occurred and spherical particles were finally obtained. The results of Nielsen’s chronomal analysis suggest that the polynuclear layer growth took place after the coalescence of the particles in the presence of larger amount of SDS.     

Microporous Silica Particles Prepared by the Salt-Catalytic Sol-Gel Process with Extremely Low Content of Water

Microporous silica was synthesized by the salt catalytic sol-gel process with extremely low content of water to tetramethoxysilane. Silica particles were precipitated even when the extent of hydrolysis was very low, since ammonium carbonate as a salt catalyst made the polycondensation faster than an acid catalyst. Microporous silica with a high surface area (680 m² g^–1) was obtained by combustion of methoxy groups at 450°C. The methoxy groups can be removed by the post-hydrolysis before heating. A high specific surface area (>750 m²g^–1) of microporous silica was obtained with pore diameter between 1.2 and 2.0 nm.     

Rapid Scheme of Silicate Analysis Based on The Lithium Metaborate Fusion Followed By Atomic Absorption Spectrometry I. Determination of Silica

Abstract

A method for the rapid determination of silica in silicates is given based on the superior lithium metaborate fusion with a view to the development of a total atomic absorption scheme of silicate analysis using this fusion. Interferences usually associated with solutions of this nature are studied. Results are given for several standard silicate samples.     

立方介孔相含钕氧化硅的合成与表征

以十六烷基三甲基溴化铵为结构导向剂，通过水热法合成了具有立方结构的含钕Nd-MCM-48介孔分子筛材料。XRD和TEM测试表明当n_Nd/n_Si<0.05时可以获得典型的长程有序介孔立方结构相，随n_Nd/n_Si比的增加，晶胞参数的增大和红外吸收光谱(FT-IR)的变化为Nd进入介孔分子筛骨架中提供了有力证据。N₂吸附-脱附实验给出了其BET表面积为1 195 m²·g^-1，BJH平均孔径为3.6 nm。紫外-可见漫反射光谱(UV-Vis)证明钕氧形成一种八面体结构。X射线光电子能谱(XPS)进一步证明钕主要以三价形式存在于立方介孔分子筛骨架中。     

碳氟基团修饰的疏水微孔二氧化硅膜制备与表征

采用三氟丙基三乙氧基硅烷（TFPTES）和正硅酸乙酯（TEOS）作为前驱体,通过溶胶-凝胶法制备了三氟丙基修饰的SiO2膜材料。利用扫描电镜、N2 吸附、 红外光谱仪以及视频光学接触角测量仪对膜的断面形貌、孔结构以及疏水性能进行了表征。结果表明,随着三氟丙基三乙氧基硅烷加入量的增大,膜的疏水性逐渐增强,膜的孔结构基本保持不变。当TFPTES/TEOS的摩尔比例达到0.6时,膜对水的接触角达到 111.6°±0.5º,膜材料仍保持良好的微孔结构,其孔体积为0.19cm3•g-1,孔径为0.97nm。     

苯基修饰的疏水微孔二氧化硅膜的制备与表征

采用苯基三乙氧基硅烷(PTES)和正硅酸乙酯(TEOS)作为前驱体,通过溶胶-凝胶法制备了苯基修饰的SiO2膜材料。利用扫描电镜、N2吸附、视频光学接触角测量仪、热重分析、红外光谱等测试手段对膜的孔结构以及疏水性能进行了表征,最后还研究了修饰后膜材料在室温条件下的单组份气体渗透和分离性能。结果表明,随着PTES加入量的增大,膜材料的疏水性逐渐增强,当PTES/TEOS和H2O/TEOS的化学计量比分别达到0.6和9.6时,膜材料对水的接触角达到115±0.5°,仍保持良好的微孔结构,其孔体积为0.17cm3/g,孔径为0.4-0.5nm。室温下氢气在修饰后SiO2膜的输运既遵循发生在微孔孔道的表面扩散机理也遵循发生在较大孔道或者微缺陷的努森扩散机理,膜材料的H2渗透率达到1.49×10-6mol?m-2?Pa-1?s-1,H2/CO2 和H2/SF6的理想分离系数分别达到4.64和365.59     

Synthesis of spherical silica particles by sol‐gel method and application

Spherical silica particles were synthesized using the sol‐gel method by hydrolyzing tetraethyl orthosilicate (TEOS) with an alkali catalyst, and it was investigated how the experimental conditions (the reaction temperature, the concentration and dropping rate of the hydrolysis catalyst solution) affected the size and morphology of silica particles. Furthermore, the silica particles were doped with sodium fluoride to measure their ion release ability. The mean diameters of the silica particles changed according to the reaction temperature and the dropping rate of the hydrolysis catalyst, namely the higher the reaction temperature or the slower the dropping rate the smaller are the mean diameters. The surface area of the silica particles was significantly different depending on the dropping rate of the hydrolysis catalyst, namely the slower the dropping rate the larger the specific surface area. The specific heat capacity and thermal reduction (TG) of the silica particles were significantly different according to the reaction temperature, namely the higher the reaction temperature the lower the specific heat capacity and the TG. It was found that the fluoride‐retaining ability was proportional to the surface area of silica particles. The fluoride ion release was equilibrated on elapsing 5 min. Copyright © 2008 John Wiley & Sons, Ltd.     

低胶体浓度条件下合成二氧化硅纳米管

在低胶体浓度条件下合成了单手螺旋二氧化硅纳米管,该纳米管可以吸收水及有机溶剂。     

Synthesis,Characterization and Applications of Immobilized Iminodiacetic Acid-Modified Silica

Porous immobilized iminodiacetic acid modified silica of the general formula S—(CH₂)₃—N(CH₂COOH)₂, (where S represents [Si—O] _n siloxane network) has been prepared by replacement of the iodide in 3-iodopropyl modified silica with diethyliminodiacetate. The immobilized-diethyliminodiacetate ligand system (S-DIDA) was then hydrolyzed by hydrochloric acid to produce the immobilized iminodiacetic acid ligand system (S-IDA). The iodo functionalized modified silica (S-I) was prepared by polycondensation of Si(OEt)₄ and (MeO)₃Si(CH₂)₃I. The XPS and CP/MAS ¹³C NMR spectra showed that not all iodine atoms are replaced and that the hydrolysis of ethyl acetate groups are incomplete upon treatment with HCl. The immobilized iminodiacetic acid ligand system exhibits high potential for the uptake of various di- and trivalent metal ions such as (Mn²⁺, Fe³⁺, Co²⁺, Ni²⁺, Cu²⁺ and Zn²⁺). Complexation of the iminodiacetate ligand system for the metal ions at the optimum conditions was found in the order: Cu²⁺ > Fe³⁺ > Ni²⁺ > Co²⁺ > Mn²⁺ > Zn²⁺. Stability studies of the iminodiacetate ligand system showed that a degradation of the siloxane network and leaching of some species occurred upon treatment with strong acid and base aqueous solutions.     

介孔分子筛MSU-1的合成

MSU X介孔分子筛具有三维立体交叉排列的蠕虫状孔道结构,有利于客体分子在其孔道内扩散[1]。目前合成MSU X的原料[2 4]TEOS水解速度慢,合成过程较易控制,但价高、易燃、有刺激性。本文采用文献[5 7]法,以水玻璃、A(EO)9为原料,在酸性至近中性的范围里合成了MSU 1介孔分子筛,与TEOS为原料的MSU 1合成进行了比较,考察了pH值和不同类型表面活性剂(脂肪醇聚氧乙烯醚和烷基酚聚氧乙烯醚)对产物结构性质的影响。1　实验部分1 1　试剂和仪器水玻璃(SiO2%≈26、Na2O%≈8),工业级,青岛海洋化工厂生产;脂肪醇聚氧乙烯醚非离子表面活性…     

Determination of Iron in Layered Crystal Sodium Disilicate and Sodium Silicate by Flame Atomic Absorption Spectrometry with Boric Acid as a Matrix Modifier

As a novel type builder for phosphate-free detergent1,2, layered crystal sodium disilicate has many advantages over other builders for phosphate detergents. The raw material of layered crystal sodium disilicate is sodium silicate. Because of the effects o…     

油页岩灰渣提取硅酸钠制备纳米二氧化硅

以油页岩灰渣提取的硅酸钠为原料,采用溶胶-凝胶法并结合多种纳米粉体分散技术,制备了分散性好、粒径均一的纳米SiO2,其平均粒径约为10 nm。 制备过程中聚乙二醇（PEG）的加入能够有效的降低纳米SiO2的表面能,减少粒子的团聚, PEG的最佳浓度为3.0%;超声振荡的空化作用所释放出的巨大冲击波和微射流,能有效地击散纳米SiO2团聚体,其最佳超声时间为0.5 h;硅酸湿凝胶与正丁醇共沸蒸馏能有效脱除凝胶中的水,防止干燥过程中颗粒间硬团聚。     

以廉价国产化试剂合成大孔径高度有序介孔氧化硅分子筛

新一代大孔径（１～３０nm）介孔分子筛在大分子转化、吸附、生物大分子分离以及电磁、传感器、光电子等领域均具有广泛的应用前景犤１～４犦。由昂贵的长链有机季铵盐阳离子表面活性剂为模板合成的MCM－４１介孔分子筛，由于其孔径小，水热稳定性差，受到了较大的限制。与其相比，以嵌段高分子共聚物为模板剂合成的介孔分子筛SBA－１５具有孔径均一，有序度高，并且其孔径大以及水热性能良好等优点，近年来得到了广泛的研究犤５～９犦。其骨架上修饰有机硅烷，可用于重金属的分离、回收，以及蛋白质的控释与分离。利用主－客体方法在SB…     

三维规则排列的大孔SiO2材料的制备及表征

 以聚苯乙烯微球离心后形成的三维规则排列的胶晶作模板，以正\r\n硅酸乙酯、水、乙醇和盐酸等配制的溶胶填充微球间的间隙，然后原位\r\n形成凝胶，最后通过焙烧除去微球得到三维规则排列大孔二氧化硅材料\r\n．以苯乙烯为原料，过硫酸钾为引发剂，在70℃下搅拌28h后得到含聚\r\n苯乙烯微球（直径约为600nm）的母液．将母液在900～1000r／min的转\r\n速下离心12～24h得到紧密堆积排列的胶晶．以正硅酸乙酯作为硅源，\r\n按n（Si（OEt）4）∶n（EtOH）∶n（HCl）∶n（H2O）＝1∶3．9∶0．\r\n3∶1．8制成透明的SiO2溶胶．溶胶浓度控制在0．5～1．0mol／L．滴\r\n加在胶晶上的溶胶靠毛细管的作用力填充入微球间隙．重复填充多次（\r\n一般不超过5次）．焙烧在流量为1L／min的空气中进行，升温速度控制\r\n在5℃／min以下．在300℃下恒温5h以除去聚苯乙烯微球，在570℃下焙\r\n烧5h．焙烧后的样品表面可观察到五颜六色的彩光．SEM分析结果表明\r\n，球形孔（孔径约500nm）大小均匀，排列整齐，保持了微球的紧密堆\r\n积排列结构．孔与孔之间由小孔窗相互交连，孔壁比较充实，壁厚约为\r\n130nm．     

Semi-Micro Preparation and Characterization of Bonded Phase ODS-Silica Prepared from Rice Husk Silica

Bonded phase ODS-silica has been prepared using purified silica prepared from rice husk by burning, reflux with sodium hydroxide solution and precipitation as a gel. The gel was spray dried, further purified by washing with concentrated hydrochloric acid then distilled water prior to vacuum drying and silanization and end-capping. The product’s physical and chromatographic properties are reported.