介孔分子筛SBA-15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,较全面地介绍了近年来SBA-15的研究状况,并展望了今后的发展方向和应用前景.     

Protein adsorption on the mesoporous molecular sieve silicate SBA-15: effects of pH and pore size

A mesoporous molecular sieve silicate, SBA-15, with three pore sizes (38.1 A, 77.3 A, and 240 A) has been synthesized using a non-ionic, tri-block copolymer as a template in a sol-gel method. The effects of synthesis conditions on the pore size and pore-size distribution of this adsorbent have been described. The adsorption of proteins on these crystalline, ordered, materials has been studied. The kinetics of adsorption and equilibrium capacity have been probed with three proteins of different dimensions. The effects of electrostatic interactions and protein size are illustrated. It has been shown that SBA-15 materials can be tailored to show size selectivity for proteins, and very high capacities (450 mg/g) can be obtained. Furthermore, the rates of adsorption are shown to be dependent on the pore size, protein structure and solution pH.     

SBA-15介孔分子筛的乙基化修饰

20世纪90年代初,美孚公司的研究者们用烷基季铵盐阳离子表面活性剂作模板剂,在碱性条件下合成出M41S系列介孔分子筛。近几年,合成出了MCM,HMS,MSU、SBA等硅基分子筛系列。由于介孔材料表面有许多端羟基,可用来固定活性基团,使其在吸附、分离、催化和主客体化学等方面具有广泛的潜在应用价值。对介孔材料孔道进行有机改性的无机-有机复合材料的研究正在兴起,本文采用分步合成法,以乙基三乙氧基硅烷为偶联剂,     

SBA-15介孔分子筛负载型过渡金属催化燃烧脱除乙腈废气

制备了具有规则孔道结构和较高比表面积的SBA-15介孔分子筛,采用真空旋转蒸发法将过渡金属(Cu,Co,Cr和Mn)负载到SBA-15表面,得到负载型过渡金属催化剂,并将其用于含氰废气催化燃烧的实验中,考察了其催化活性.催化剂的理化性能通过X射线衍射(XRD)、氮气吸附-脱附、透射电子显微镜(TEM)、H2-程序升温还...     

Acidity enhancement of SBA mesoporous molecular sieve by modification with SO4/ZrO2

The SO₄²⁻/ZrO₂ modified SBA mesoporous molecular sieves were prepared and characterized by XRD, N₂ adsorption, TG/DTG/DTA and IR pyridine chemisorption. The acidity of the molecular sieve was greatly enhanced after modification, and IR pyridine chemisorption results revealed that Lewis acidity was dominant in these samples. The catalytic activities of the modified molecular sieves towards strong and medium strong acid catalyzed reactions were lower than those of bulk SO₄²⁻/ZrO₂, but higher than those of Al-containing SBA molecular sieve from direct synthesis, whereas the activities of all these catalysts for weak acid catalyzed reaction were close to each other.     

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.     

苯基改性的中孔分子筛SBA-15的合成及其磺化

 在酸性条件下用正硅酸乙酯(TEOS)和苯基三乙氧基硅(PTES)直接缩合制备了苯基改性的中孔分子筛Ph-SBA-15,并用紫外光谱、红外光谱、X射线衍射、透射电镜和核磁共振等对改性后的样品进行了表征. 结果表明,在300 ℃下焙烧后,模板剂被脱除,而苯基可完整保留,苯基改性的SBA-15分子筛具有有序结构. 进一步用氯磺酸磺化改性后,可得到苯磺酸化的分子筛,其酸度可达4.19 mmol/g.     

改善SBA-15介孔材料水热稳定性的简单溶剂热后处理方法

提出了一种有效改善SBA-15介孔材料水热稳定性的简单溶剂热后处理方法. SBA-15材料经环己烷、甲苯和正丁醇等有机溶剂在157和190 oC密闭容器中分别处理6–24 h后,可呈现很好的水热稳定性.它们在800 oC经100%水蒸气处理12 h,依然能保持很好的有序介孔结构,比表面积可高达192–281 m2/g.其中,经环己烷190 oC溶剂热处理24 h的样品表现出最优的水热稳定性.溶剂热处理能显著提升材料孔壁中类似Si(OSi)2(OH)2和Si(OSi)3OH结构的Si–OH基间脱水,形成稳定的Si(OSi)4结构,从而有效减少了SBA-15材料孔壁的缺陷.由此,介孔材料的水热稳定性得到明显改善.溶剂热处理对SBA-15材料水热稳定性的这种提升作用与所用溶剂性质、处理温度以及SBA-15前驱体的类型密切相关.其中,以低沸点的非极性溶剂处理焙烧后的SBA-15材料表现出最好的稳定化效果.该方法具有简单、低能耗的特点,其在制备高水热稳定的有序硅基介孔材料上有很好的潜在应用价值.     

载有卟啉的介孔SBA-15表面光电压的性质研究

用表面光电压谱(SPS)和场诱导表面光电压谱(FISPS)技术对比研究了卟啉和介孔SBA-15及载有卟啉的介孔SBA-15的表面光伏特性.固载后同时显示了卟啉和介孔的光电压性质,但是光电压响应强度减弱,这是因为卟啉和介孔之间发生了电子传递的缘故.在外电场诱导下,它们的光伏响应强度随外加正电场光伏响应强度的增加而增强,随外加负电场光伏响应强度的增加而减弱.而装载后的SBA-15在334和425 nm处的光伏响应信号随外加电场的变化而有不同的变化.     

磺酸基功能化的有序SBA-15-SO3H介孔分子筛的合成及其在苯酚叔丁基化反应中的应用

通过一步法合成了SBA-15-SO3H介孔分子筛,用XRD,TEM,低温N2吸附和吡啶吸附红外光谱等方法进行了表征,并研究了其在苯酚叔丁基化反应中的催化性能.结果表明,SBA-15-SO3H保持了母体SBA-15高度有序的六方介孔结构,具有较强的酸性和热稳定性,且在苯酚叔丁基化反应中表现较好的催化活性和2,4-二叔丁基苯酚选择性.     

(SBA-15)-ZnS主-客体纳米复合材料的制备与表征

本研究在SBA-15分子筛孔道中制备了纳米ZnS。Zn_{2+首先通过离子交换交换到SBA-15中,通过水热法在SBA-15分子筛孔道中制备了纳米ZnS。(SBA-15)-ZnS复合物由粉末X-线衍射,傅立叶变换红外光谱,低温氮气吸附-解析附技术,固体扩散漫反射光谱以及发光研究进行了表征。粉末X-线衍射研究说明在制备主-客体纳米复合材料中分子筛骨架未被制备过程所破坏,保持完整且结晶度仍很高。傅立叶变换红外光谱表明制备的材料骨架完好。77 K低温氮气吸附-解析附研究表明所制备的复合材料孔体积,孔尺寸以及表面积相对于SBA-15分子筛降低,证明客体ZnS已成功地组装入分子筛孔道中。所制备的纳米复合材料固体扩散漫反射吸收光谱相对于体相ZnS显示出蓝移表明,ZnS已限制在分子筛的孔道中且复合材料中分子筛的孔道对ZnS具有明显的立体限域效应,ZnS成功地组装在SBA-15分子筛的孔道中。发光研究表明,(SBA-15)-ZnS样品出现明显发光现象。主-客体复合材料具有良好的发光性能,有望在发光材料领域中获得应用。}     

Modification of mesoporous silicate SBA-15 with tris[bis(trimethylsilyl)amido]samarium and its utility in Tishchenko reaction

Treatment of mesoporous silicate SBA-15 with Sm[N(SiMe₃)₂]₃ led to the formation of a novel organolanthanide/inorganic hybrid material [SBA-15]Sm[N(SiMe₃)₂]_x via abstraction of N(SiMe₃)₂ by terminal silanol groups and subsequent surface silylation. The hybrid material was characterized by elemental analyses, IR spectroscopy, X-ray diffraction, and nitrogen sorption, indicating a successful tailoring inside the silicate SBA-15 and the maintenance of the well-ordered mesostructure. This hybrid material is a promising heterogeneous catalyst for the Tishchenko reaction, where it is superior to the homogeneous correspondent in deactivation behavior, reusability and relative tolerance to oxygen, particularly in the control of selectivity of mixed Tishchenko reaction due to the steric hindrance and the diffusion control derived from the surface confinement.     

SBA-15负载金属[Co(Ⅱ),Zn(Ⅱ)]酞菁催化剂的制备及其催化氧化性能

以1,8-二氮杂双环[5,4,0]十一碳烯-7为催化剂,4,5-二丁氧基邻苯二甲腈为原料,用液相法合成了两种金属酞菁配合物——β-八(丁氧基)酞菁钴(1)和β-八(丁氧基)酞菁锌(2),其结构经UV-Vis和IR表征。采用浸渍法将1和2分别负载到有序介孔分子筛SBA-15上制得SBA-15负载金属酞菁催化剂SBA1-15和SBA2-15。以0.1 mol.L-1亚硫酸钠的氧化反应为探针反应,研究了常温常压、氧气气氛下,SBA1-15和SBA2-15的催化氧化活性,并考察了SBA1-15的用量对其催化活性的影响及重复利用性。结果表明,两种催化剂均具有良好的催化性能,在用量相同时,SBA1-15的催化氧化性能优于SBA2-15;SBA1-15的质量为溶液质量的0.16‰时,催化活性最佳,且可以重复使用。     

Immobilization of acetylcholinesterase on screen-printed electrodes: comparative study between three immobilization methods and applications to the detection of organophosphorus insecticides

The analytical performance of three acetylcholinesterase (AChE) screen-printed biosensors designed for the detection of pesticides are evaluated. Bioencapsulation of the enzyme in a sol-gel composite and immobilization by metal-chelate affinity were compared with the entrapment of the enzyme in a photopolymerisable polymer. A very low amount of enzyme ranging between 0.8 and 1.2 mIU was immobilized on the electrode surface in each approach. The sensors exhibited a storage stability of over 6 months when the enzyme was encapsulated in a polymer film. Pesticide concentrations in the range of 10⁻⁸ to 10⁻⁹ M paraoxon, dichlorvos and chlorpyrifos ethyl oxon could be detected according to each configuration by following an incubation time of 20 min.     

表面含磷酸的介孔分子筛P-SBA-15的合成及其性能评价

采用后合成法,将磷酸固载在纯硅介孔分子筛SBA-15表面上。利用X射线衍射（XRD）、红外光谱（IR）、氮气吸附 脱咐法（BET）分析方法表征催化剂的物理性能。结果表明,催化剂P-SBA-15在高温焙烧后保持了稳定的介孔分子筛SBA-15结构,该催化剂的比表面积和孔径分别为605.45m2/g和5.576nm（磷硅摩尔比5%）。选用十一碳烯酸与异丙醇的酯化反应对催化剂P-SBA-15的催化反应性能进行评价,同时与其他几种微孔沸石分子筛催化剂催化性能相比表明,磷酸改性的介孔分子筛P SBA 15是合成十一烯酸异丙酯较为理想的固体酸催化剂,考察了催化剂的稳定性。     

Ru/SBA-15的制备及其对水煤气变换反应的催化作用

制备了中孔分子筛SBA-15,以SBA-15为载体采用真空浸渍法制备了负载型Ru基水煤气变换反应的催化剂。利用透射电子显微镜、X-射线粉末衍射等方法对样品进行了表征。结果表明,合成的SBA-15分子筛孔径约为8 nm,粒径约为1 nm的Ru纳米粒子均匀分布在分子筛孔道中,添加适量的La2O3助剂可以显著提高催化剂的低温活性。当Ru和La2O3的负载量分别为4%和8%时,R4L8/SBA-15催化剂对CO转化率在255℃和265℃下分别达到56%和98%。     

PW_(11)/SBA-15介孔杂化材料的直接合成与表征

采用三嵌段共聚物EO20PO70EO20(P123)为模板剂,正硅酸乙酯(TEOS)和缺位Keggin型多金属氧酸盐Na7PW11O39(PW11)为无机前驱体,由共缩合法一步合成了PW11/SBA-15介孔杂化材料.通过红外(IR)光谱、紫外-可见漫反射光谱(UV-Vis/DRS)、X射线衍射(XRD)、低温N2吸附、透射电子显微镜(TEM)等手段对杂化材料和合成过程进行了表征.结果表明:杂化材料中不仅多金属氧酸盐的Keggin单元保留完整,且共价键联于介孔孔道内部,而且样品基本具有规整有序的六方介孔结构.TEOS预水解时间的长短对有序结构的构筑有明显影响,随预水解时间延长,样品的介观有序性增加.这是因为多金属氧酸盐对模板剂P123有盐析作用,其作用大小与多金属氧酸盐前驱物的溶解度有关.     

Preparation, Characterization and Catalytic Performance of La-SO42-/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.     

萘在介孔分子筛MCM-41与SBA-15上的吸附特性研究

对低浓度气相萘在两种常见介孔分子筛MCM-41和SBA-15上的吸附特性进行研究。得到了萘在两种吸附剂上的吸附等温线和不同初始浓度下的穿透曲线,并分别与吸附等温线模型(Langmuir、Freundlich、D-R)和恒定浓度波动力学模型进行了拟合。结果表明, Langmuir模型能很好描述低浓度气相萘的吸附等温线(R²均在99%以上);具有微孔结构的SBA-15对萘的吸附能力要优于仅具备介孔结构的MCM-41。动力学模型在初始浓度较低时能较好地预测萘在吸附剂上的穿透曲线,且在SBA-15上的相关系数高于MCM-41;萘在2.76 mol/L时具有较大介孔的SBA-15的总传质系数K_a更高,表明萘在SBA-15上的总传质阻力更低,更能较快达到传质平衡。     

Effects of Morphology and Structural Characteristics of Ordered SBA-15 Mesoporous Silica on Release of Ibuprofen

Three kinds of highly ordered SBA-15 mesoporous materials with different pore sizes and morphologies denoted as LPS-SBA-15 (stick-like with pore size 7.28 nm), CPS-SBA-15 (stick-like with pore size 5.96 nm) and T-SBA-15 (tablet-like with pore size 4.64 nm) have been prepared, characterized and employed as carrier materials. The release behaviors of the ibuprofen in a simulated body fluid from these mesoporous silica materials were studied. The influences of pore size and exterior morphologies of mesoporous silica on the release behaviors of ibuprofen have been investigated. It has been found that the release becomes fast with increasing of pore size and slow with extending of transport pathway, and that the release rate of ibuprofen from the three kinds of SBA-15 is LPS-SBA-15 > T-SBA-15 > CPS-SBA-15. The results show that the inner structure as well as the exterior morphologies of SBA-15 mesoporous silica can seriously affect the release behaviors of ibuprofen.