氨基功能化SBA-15介孔分子筛的制备与表征

以3-氨丙基三乙氧基硅烷为偶联剂,采用后合成法对介孔分子筛(SBA-15)的表面进行改性,制得氨基功能化的介孔NH<,2>-SBA-15材料(简称NH<,2>-SBA-15),其结构和性能经FT-IR,元素分析,XRD,SEM及低温N<,2>吸附-脱附表征.结果表明,氨基成功地嫁接到SBA-15表面,含量高达3.47 ...     

功能化有序介孔二氧化硅材料在分析样品前处理中的应用

功能化有序介孔二氧化硅材料具有均一可调的介孔孔径、规则的孔道、稳定的骨架结构、易于修饰的内表面和较高的比表面积、高的吸附容量等特性,可用于生物、医药、环境样品等复杂基体中痕量分析物的高选择性分离与富集,因此在样品前处理中的应用特别引人瞩目。文中简要介绍了功能化有序介孔二氧化硅材料的制备方法,综述了功能化有序介孔二氧化硅材料在分离富集金属离子、有机污染物以及生物大分子样品前处理中的应用进展。     

有机功能化介孔氧化硅的制备和表征

有机功能化的介孔氧化硅在催化领域、吸附分离、生物化学和电子学等领域有广泛的应用前景。本文综述了近年来有机功能化介孔氧化硅的研究进展,主要介绍了有机功能化的介孔氧化硅的制备方法、种类和表征手段,并对其未来发展前景进行了展望。有机功能化的介孔氧化硅的制备方法主要有接枝法、共缩聚法、有序介孔有机硅法和自模板法,常用的表征方法有粉末X-射线衍射分析、低温N₂吸附-脱附、透射电镜、红外光谱、热重分析、元素分析和²⁹Si、¹³C交叉极化和魔角旋转核磁共振等。     

环氧基功能化SBA-15介孔分子筛的制备、表征及其固定化青霉素酰化酶

利用表面嫁接法和乙烯基环氧化法制备了环氧基团功能化介孔分子筛G-SBA-15和O-SBA-15,并对其结构和表面性质进行了表征.结果表明,G-SBA-15和O-SBA-15均具有良好的长程有序结构,二者环氧基团的含量分别为0.78 mmol/g和0.37 mmol/g,在O-SBA-15表面还存在一定数量的乙烯基基团.G-SBA-15和O-SBA-15用于固定青霉素酰化酶(pen ic illin G acylase,PGA),固定化酶PGA/G-SBA-15和PGA/O-SBA-15在37℃时水解青霉素G钾制备6-氨基青霉烷酸(6-APA)的表观活性分别为1075 IU/g和1761 IU/g.PGA/G-SBA-15经4次使用后表观活性趋于稳定,经10次使用后保持其初始活性的83.7%.PGA/O-SBA-15在重复使用中,表观活性出现持续衰减,10次使用后保持其初始活性的51.6%,PGA/G-SBA-15的操作稳定性明显好于PGA/O-SBA-15.     

功能化介孔二氧化硅的制备及其吸附分离水中铀的研究进展

铀是一种高效、清洁的核能燃料,但在核工业中不可避免地会产生含铀废水。如果不及时处理,泄漏到环境中,将对动植物和人类的健康构成威胁。因此,从能源回收和环境保护的角度来说,研究水溶液中U(Ⅵ)的分离工艺迫在眉睫。吸附技术因其可行性、效率高和操作简单等优点备受关注。功能化介孔二氧化硅材料具有比表面积大、孔容量大和吸附能力强等优点,是一种理想的吸附剂,在铀的吸附分离领域有着广泛的应用。本文在功能化介孔二氧化硅制备方法的基础上,结合X射线光电子能谱、傅里叶变换红外光谱、X射线吸收精细结构谱、X射线能谱分析和拉曼光谱等分析方法,对国内外目前水溶液中U(Ⅵ)吸附的表征及吸附机理进行了综述。虽然功能化介孔硅吸附铀已经取得了令人鼓舞和潜在的发展,但新型多功能吸附剂的设计和批量生产在实际环境的应用方面仍具有挑战性。     

磺酸基团功能化的碳-硅介孔复合材料的制备及其在生物柴油绿色合成中的应用(英文)

利用化学浸渍法将蔗糖负载到 SBA-15 介孔材料孔道内部, 高温炭化形成的多聚苯环经发烟硫酸气相磺化处理后, 得到磺酸基团功能化的新型碳-硅介孔复合材料. 发烟硫酸气相磺化处理是该材料合成的关键步骤. X 射线衍射、扫描电镜和氮气吸附结果表明, 碳-硅介孔复合材料经磺酸化处理保持了高度有序的介孔结构. 热重、傅里叶变换的红外光谱及吡啶吸附红外光谱结果证明, 磺酸功能基团成功的嫁接于碳-硅介孔复合材料孔道的内表面, 反应活性中心为 Br?nsted 酸, 酸密度在 0.09~0.70 mmol/g 可以有效调变. 当碳负载量为 35% 时, 该复合材料在生物柴油的绿色合成中显示出最优的催化性能, 且可重复使用 3 次以上.     

SBA-15固载金属氧化物介孔材料的研究进展

介孔分子筛SBA-15具有独特的物理化学性质和广阔的应用前景,成为目前众多研究领域的一个研究热点。本文结合我们自己的工作和国内外相关研究,较全面地阐述了近年来几种SBA-15固载金属氧化物介孔材料的研究状况,并展望了今后其研究、发展方向和应用前景。     

磺酸功能化三维有序大孔材料的制备与催化性能研究

采用模板法, 用正硅酸乙酯和3-巯丙基-三甲氧基硅烷的混合溶胶, 在聚苯乙烯胶晶间隙中原位转化, 除去模板后用双氧水将巯基氧化成磺酸基, 首次成功地制备了大孔规整排列的3DOM SiO₂-SO₃H材料. 样品用SEM, EDS, FT-IR等方法进行了测试表征. 结果表明, 所得到材料的三维大孔结构规整性十分好, 大孔孔径大约250 nm, 并由大约80 nm的小孔相连; 磺酸基很好地嵌入孔壁基质中, 吡啶吸附测定显示了典型的质子酸特征, 而且酸中心随硫含量增加而增多. 对乙酸与正丁醇的酯化反应显示了良好的催化性能, 磺酸含量越大, 催化活性越高. 这一研究为开发新型高效的固体酸催化剂提供了很有意义的结果.     

硼酸功能化介孔纳米材料的制备及其对糖肽的富集研究

制备了一种硼酸功能化介孔纳米材料, 利用硼酸基团可以和糖肽中糖链上的顺式邻位或间位羟基发生反应形成环状二酯对糖肽进行富集, 考察并比较了不同的孵育时间、孵育缓冲液、清洗方式以及洗脱液对糖肽富集的影响, 优化了该材料富集糖肽的条件, 建立了一种硼酸功能化介孔纳米材料用于选择性富集糖肽并用基质辅助激光解吸附电离-四极离子阱-飞行时间质谱(MALDI-QIT-MS)进行糖肽分析的方法.     

表面高巯基功能化介孔材料的制备及对Hg~(2+)的吸附性能

在酸性条件下,以三嵌段非离子表面活性剂P123为模板剂,四氧基硅烷(TEOS)预水解后与3-巯基丙基三乙基硅(MPTES)共聚,合成了具有不同巯基官能团比例x[n(MPTES)/n(TEOS+MPTES)]的功能化介孔材料(SBA-SH-x),其结构和性能经FT-IR,元素分析,SEM,TEM,小角X-ray和N2吸附-脱附表征。结果表明:x10%,SBA-SH-x为六方p6mm介观结构;10%x15%,SBA-SH-x为立方Ia3d介孔结构;x20%,SBA-SH-x为无序结构。SBA-SH-x在水溶液中吸附Hg2+的研究结果表明:SBA-SH-10和SBA-SH-15对Hg~(2+)吸附性能较好。     

Assembly of heteropoly acid nanoparticles in SBA-15 and its performance as an acid catalyst

Keggin‐type 12‐tungstophosphoric acid (TPA) nanocrystals have been assembled inside the pores of mesoporous silica through a vacuum impregnation method by using large‐pore SBA‐15 as a nanoreactor. The product was characterized by Brunauer–Emmet–Teller particle size distribution (BET‐PSD), NMR and FT‐IR spectroscopy, X‐ray diffraction (XRD), tranmsission electron microscopy (TEM), differential thermal analysis (DTA) and FT‐IR of adsorbed pyridine. The experimental results illustrate that the TPA nanocrystals are excellent Brønsted acid catalytic materials at room temperature.     

Mesoporous silica SBA-15 functionalized with phosphonate and amino groups for uranium uptake

Mesoporous silicas have a very attractive ability of sorption and enrichment of metal ions due to their huge surface area and facile functionalization by organic ligands.In this work,phosphonate-amino bifunctionalized mesoporous silica SBA-15(PA-SBA-15) as U(VI) sorbent was fabricated through post-grafting method.The obtained mesoporous silica was characterized by SEM,XRD,NMR and nitrogen sorption/desorption experiments,which revealed the existence of ordered mesoporous structure with uniform pore diameter and large surface area.The adsorptivity of PA-SBA-15 for U(VI) from aqueous solution was investigated using batch sorption technique under different experimental conditions.The preliminary results show that the U(VI) sorption by PA-SBA-15 is very quick with equilibrium time of less than 1 h,and the U(VI) uptake is as large as 373 mg/g at pH 5.5 under 95 ℃.The sorption isotherm has been successfully modeled by the Langmuir isotherm,suggesting a monolayer homogeneous sorption of U(VI) in PA-SBA-15.The sorption is pH-dependent due to the pH-dependent charge of sorbent in the aqueous solution.The thermodynamics research shows that the sorption is a feasible and endothermic process.Based on these results,PA-SBA-15 could be a promising solid phase sorbent for highly-efficient removal of U(VI) ions from waste water and enrichment of U(VI) from a solution at a very low level.     

含钨SBA-15介孔分子筛催化剂的表面酸性和羟基分布

分别以浸渍法和水热晶化法制备了SBA-15介孔分子筛孔中插入氧化钨和碳化钨的催化剂,采用NH3-TPD测定了表面酸性和总酸量,并采用FT-IR研究了它们的表面羟基分布情况.NH3-TPD结果表明,浸渍法制备的含氧化钨的SBA-15介孔分子筛催化剂表面只有SBA-15介孔分子筛的弱酸位,而含碳化钨的SBA-15介孔分子筛催化剂表面还出现了W2C的强酸位.水热晶化法制备的含氧化钨的SBA-15介孔分子筛催化剂表面SBA-15介孔分子筛的弱酸位随W含量的增大略有增强, W含量较高时还出现了钨物种的强酸位;含碳化钨的SBA-15介孔分子筛催化剂表面除了SBA-15介孔分子筛的弱酸位外, W含量较低时有W2C的强酸位, W含量较高时有W2C和WC两种强酸位.傅里叶变换红外光谱结果表明,浸渍法和水热晶化法制备的含氧化钨和碳化钨的SBA-15介孔分子筛催化剂除表面自由硅羟基外,还存在着α, β和γ三种不同类型的氢键羟基,并且氢键羟基和催化剂的制备方法以及催化剂的W含量都有一定的关系.     

负载型P-Mo-V/SBA-15催化剂上的甲烷选择氧化反应

以磷钼钒杂多酸(H₅PMo₁₀V₂O₄₀)为前驱体、介孔SBA-15为载体, 采用浸渍法制备不同负载量的P-Mo-V氧化物催化剂. 在甲烷选择氧化反应中, 考察了负载量、反应温度、空速等对甲烷转化率和产物选择性的影响. 结果表明, 催化剂对甲烷选择氧化制甲醛具有较高活性, 甲烷转化率随负载量的增大和反应温度的升高而提高, 甲醛的选择性随负载量的增大先升后降. 反应温度为640 ℃、空速为48300 L•kg^－1•h^－1、氧化物负载量w＝2.89%时, 甲醛的时空产率最高(295 g•kg_cat^－1•h^－1). 多种表征表明, 氧化物负载量w≤2.89%时, P-Mo-V氧化物在载体介孔孔道内以高分散形式存在. 催化剂的酸性和氧化还原性质与负载量相关, NH₃-TPD和H₂-TPR的测试结果表明, 较弱的酸性位和较低还原温度的活性组分有利于甲烷选择氧化制甲醛.     

A small-angle neutron scattering study of the ethyl (n-octyl) phosphate micelles in water

Summary Mixed-double chain anionic surfactants, barium- and lithium-salts of ethyl(n-octyl) phosphate (EOP), which are asymmetric in the molecular shape, and a series of identical chain di-n-alkyl phosphate lithium salts have been synthezized. The limiting partial molar volume of a PO ₄ ^– group (23.43±0.41 cm³ mol^–1) for use in small-angle neutron scattering analysis was determined by density measurements of a series of identical chain di-n-alkyl phosphate lithium salts. For lithium EOP-D₂O system, a critical micellar concentration (2.3 wt%) was determined by³¹P NMR spectra. The micellar shape and size in the EOP-water binary system has been investigated by using small-angle neutron scattering (SANS) spectra. It has been found that the micelles of barium EOP in water have the shape of a prolate spheroid and aggregation numbers (n) equal to 48 at 23°C and 52 at 50°C. For the lithium EOP-micellar system, it has been found that the minimum micelle with an aggregation numbern=21 is spherical and micellar growth and variation from the spherical to the prolate shape might occur with an increase in concen tration above the CMC.     

适合SBA-15介孔材料工业化生产的改良方法

在SBA-15介孔材料100L中试和2m3工业放大合成基础上,采用多次水解合并晶化、母液循环使用和以工业正硅酸乙酯(TEOS)原料为硅源三种改良方法,提高SBA-15材料的合成效率,减少废酸水排放和降低原料成本.结果表明,母液经加热蒸除乙醇至5%和工业原料TEOS经蒸除沸点低于163oC的前馏分后使用,在有效保证合成出结构性能良好SBA-15材料的同时,可使生产效率提高1倍,分别减少50%和90%三嵌段共聚物和盐酸用量,且几乎无废水排放,最终节约SBA-15原料成本约60%.这些改良方法有利于SBA-15材料工业生产时的环境保护和成本控制,具有很高可行性.     

Preparation, Characterization and Catalytic Performance of La-SO4/SBA-15 in Esterification of Acetic Acid with n-Butanol

La-SO42-/SBA-15 was synthesized with various amounts of lanthanum via incipient-wetness impregnation. Characterization was done by X-ray diffraction（XRD）, transmission electron micrographs（TEM）, nitrogen adsorption, FTIR spectroscopic analysis, thermogravimetric analysis, and the total amount of acidity of catalyst was estimated by TPD of NH3. The results indicate that lanthanum has been incorporated into SBA-15 molecular sieve. The prepared materials（La-SO42-/SBA-15） keep the highly ordered mesoporous two-dimensional hexagonal structure and do not change the mesoporous channel structure of the support SBA-15. The catalyst showed best catalytic activity in the synthesis of n-butyl acetate. The optimum conditions of the esterification by orthogonal experiments were studied： the molar ratio of n-butanol to acetic acid 1：1.2, the amount of catalyst 7.5%, reaction time 80 min. The yield of n-butyl acetate could reach 93.2% under the optimum conditions. The catalyst was recyclable, cost effective and environmental friendly.     

Initial stages of SBA-15 synthesis: an overview

This work presents an overview of the data obtained for SBA-15 synthesis under the reaction conditions using synchrotron based small angle X-ray scattering and small angle neutron scattering. Three major stages in the synthesis of SBA-15 materials proceeding according to the cooperative self-assembly mechanism have been identified, and the structures of the intermediates species have been established. Our in situ time-resolved neutron scattering experiments demonstrate that only spherical micelles of the templating agent are present in the synthesis mixture during the first stage of the reaction. According to the neutron scattering and X-ray scattering data, in the second stage of the reaction the formation of hybrid organic-inorganic micelles is accompanied with the transformation from spherical to cylindrical micelles, which takes place before the precipitation of the ordered SBA-15 phase. During the third stage, these micelles aggregate into a two-dimensional hexagonal structure, confirming that the precipitation takes place as the result of self-assembly of the hybrid cylindrical micelles. As the synthesis proceeds, the voids between the cylinders are filled with the silicate species which undergo condensation reactions resulting in cross-linking and covalent bonding, leading to the formation of highly ordered SBA-15 mesostructure. This work demonstrates that valuable structural information can be obtained from X-ray and neutron scattering characterisation of complex systems containing periodic phases with d-spacing values up to 30 nm, and that both techniques are powerful means for in situ monitoring of the formation of nanostructured materials.     

介孔分子筛SBA-15的脂肪酶固定量分析测定

利用吸附法将假丝酵母脂肪酶(candida rugosa lipase,CRL)固定在介孔分子筛SBA-15上,对比了由单波长紫外分光光度法、双波长紫外分光光度法和二辛可宁酸法(bicinchoninic acid method, BCA)法测定的酶蛋白浓度及酶蛋白固定量.结果表明: SBA-15对紫外吸收有明显干扰,单波长紫外法测定结果远大于双波长紫外法和BCA法,双波长紫外法和BCA法测定结果较接近.利用BCA法测定了不同浓度CRL在介孔分子筛上的固定量,考察了固定化酶的泄漏量.在编号分别为Lu001和LLSD1的介孔分子筛SBA-15上的载酶量分别为16.6和114.12 mg/g.在缓冲溶液中SBA-15固定化酶的泄漏率只约为0.5%,可作为良好的酶固定化载体.     

硅烷偶联剂改性SBA-15固载Keggin型杂多酸催化合成柠檬酸三丁酯

以3-(甲基丙烯酰氧)丙基三甲氧基硅烷(MEMO)表面改性的介孔分子筛SBA-15为载体,制备了一系列介孔分子筛/硅烷偶联剂@杂多酸复合催化剂SBA-15/MEMO@HnXW12O40(X=P⁵+,Si⁴⁺,B³⁺;n=3,4,5),并利用FTIR、P-XRD、TEM、N2吸附-脱附对其结构进行表征。以SBA-15/MEMO@HnXW12O40(X=P⁵⁺,Si⁴⁺,B³⁺;n=3,4,5)为负载型杂多酸催化剂对柠檬酸三丁酯的催化合成进行研究,分别考察了酸醇摩尔比、催化剂用量、反应温度、反应时间对催化合成柠檬酸三丁酯酯化率的影响,并获得合成柠檬酸三丁酯的最佳工艺条件。结果表明:当负载型硅钨酸催化剂的负载量为50%、催化剂用量为3.8%、酸醇摩尔比为1∶4、反应温度为140℃、反应时间为6 h、环己烷用量为5 mL时酯化率可达97.56%,重复使用7次后酯化率仍可达62.67%。