Ag-SBA-15抗菌剂的制备及其性能研究

以板状和纤维状SBA-15为载体,采用正己烷为疏水溶剂、硝酸银的水溶液为亲水溶剂的双溶剂法制备了广谱抗菌剂板状Ag-SBA-15和纤维状Ag-SBA-15。以X射线衍射、扫描电子显微镜、透射电子显微镜和X射线能谱等手段表征了抗菌剂的结构和特性。通过试管稀释法考察了抗菌剂抗菌性能。结果显示,两种形貌SBA-15为载体制得的Ag-SBA-15都保持高度有序的二维六方相介孔结构,银颗粒在载体中均匀分散。试管稀释法测得由板状SBA-15制得抗菌剂对金黄色葡萄球菌的最小抑菌浓度达8ug/m L,而相应条件下由传统纤维状SBA-15为载体制得的抗菌剂最小抑菌浓度为32ug/m L。     

HCl对有序介孔氧化硅结构与形貌的影响

以三嵌段共聚物P123为有机模板导向剂、正硅酸乙酯TEOS为无机硅源, 在HCl存在的强酸性环境下, 采用水热法合成了有序介孔分子筛SBA-15. 采用XRD、SEM、TEM、N2吸附-脱附等手段对产物的结构与形貌进行了分析, 考察了HCl用量对有序介孔材料结构及形貌的影响. 结果表明, 在合成有序介孔氧化硅时, HCl发挥了催化和中间离子的双重作用, 促使棒状胶束形成六方有序排列, 降低SBA-15中微孔的数量, 而且对合成有序介孔氧化硅SBA-15的形貌有显著影响. 适宜的HCl用量对形成“珍珠链状”形貌的、热稳定性优良的SBA-15介孔材料具有重要作用.     

一步法直接合成有机季铵功能修饰的介孔分子筛SBA-15

以P123 嵌段共聚物为模板剂, 3-三甲基丙基氯化铵三甲氧基硅烷(TMAPS)为修饰剂, 酸性条件下一步法直接合成了有机季铵基团功能修饰的SBA-15, 并通过XRD、TEM、N2吸附-脱附、Raman 光谱等对功能化样品的结构和性质进行了表征, 对一步法合成TMAPS 修饰的SBA-15 的可能反应机理进行了探讨. 修饰后的SBA-15 仍然保持了二维六方特征介孔结构, 随着TMAPS负载量的增大, SBA-15 孔道有序度下降, 孔径、孔容和比表面积也随之下降. 有机季铵基团在SBA-15 孔道表面均匀分散, 可与HAuCl4通过快速离子交换制备Au 颗粒高度分散的Au-SBA-15.     

SBA-15的孔壁碳膜修饰对钴基催化剂结构与催化性能的影响

在惰性气体中焙烧SBA-15制得孔壁被碳修饰的SBA- 15C样品,以它和SBA-15为载体,采用等量浸渍法制备了负载型Co基催化剂,并运用X射线衍射、N2物理吸附、程序升温还原、NH3吸附量热等手段对样品进行了表征.结果表明,SBA- 15C仍保持原有的六方有序的中孔结构,但其孔壁经碳修饰后发生增厚,比表面积略有下降...     

pH值响应性毒死蜱/铜席夫碱配合物改性SBA-15的制备及缓释性能

以3-氨丙基三乙氧基硅烷（APTES）、水杨醛和铜离子为改性剂,通过后嫁接法制得铜席夫碱配合物改性SBA-15（Cu-SBA-15）,并以毒死蜱为模型药物,制备了毒死蜱/铜席夫碱配合物改性SBA-15缓释体系。利用TEM、SEM、XRD、N₂吸附-脱附、TG、FTIR和XPS对SBA-15、氨基改性SBA-15（NH₂-SBA-15）、水杨醛希夫碱改性SBA-15（SA-SBA-15）的形貌、结构和Cu-SBA-15的配位情况进行了表征,考察了SBA-15在改性前后对毒死蜱的吸附量和缓释性能,并着重探究了毒死蜱/铜席夫碱配合物改性SBA-15载药体系在不同pH值下的释药行为。结果表明,APTES和水杨醛能够通过后嫁接法修饰于SBA-15,修饰后仍保持十分有序的孔道结构。SBA-15通过改性后,其对毒死蜱的吸附量由100 mg·g^-1增加至195 mg·g^-1,且其对药物的缓释性能也得到改善。毒死蜱/铜席夫碱配合物改性SBA-15缓释体系显示出明显的pH值响应性,pH=3时的释药速率大于pH=11时,而在中性条件下的缓释效果相对最好。载药体系的释药行为可用Riger-Peppas动力学模型来描述,其药物释放由Fick扩散控制。     

疏水性Cosalen/SBA-15的制备及在甲苯选择性氧化中的应用

以介孔分子筛SBA-15为载体, 先采用γ-氨丙基三乙氧基硅烷(APTES)进行氨基硅烷化修饰, 然后经甲基三乙氧基硅烷(MTES)疏水修饰后固载双水杨醛缩乙二胺合钴配合物(Cosalen). 采用傅里叶变换红外光谱、 紫外-可见漫反射光谱、 X射线光电子能谱、 元素分析、 等离子体发射光谱、 X射线衍射和氮气物理吸附等手段对制备的固载型催化剂Cosalen/SBA-15进行了物相结构和修饰程度的表征, 并考察了样品对甲苯、 苯甲醛和苯甲醇的吸附性能及在甲苯液相氧化反应中的催化性能. 结果表明, 固载型催化剂Cosalen/SBA-15的介孔结构和孔道有序性保持良好, Cosalen通过与氨基配位固载在修饰后的载体SBA-15上, 且高度分散, 氨基硅烷化和甲基修饰明显增强了其表面疏水性能, 对苯甲醛和苯甲醇的吸附量降低. 疏水性Cosalen/SBA-15协同N-羟基邻苯二甲酰亚胺(NHPI)催化甲苯液相分子氧氧化反应, 无溶剂体系在130 ℃下反应2 h, 甲苯转化率达到16.0%, 产物中苯甲醛和苯甲醇的总选择性为32.0%, 在一定程度上抑制了极性产物深度氧化为苯甲酸. 高温不利于苯甲醛和苯甲醇选择性的提高, 降低温度至110 ℃, 甲苯转化率达到12.9%时, 苯甲醛和苯甲醇的总选择性提高到43.9%.     

Co-NH2-SBA-15的制备及其脱硫性能研究

采用水热合成法制备介孔分子筛SBA-15,用（CH₃COO）₂Co对其进行超声浸渍改性,并用硅烷偶联剂APTS将氨基引入SBA-15分子筛中,制备出Co-NH₂-SBA-15吸附剂,考察了常温条件下H₂S的吸附性能。通过SEM、XRD、FT-IR、BET、XPS等表征手段对吸附剂进行表征。结果表明,氨基与金属同时负载在分子筛表面,氨基与硅物质的量比为0.20,Co负载质量分数为8%的SBA-15吸附效果最好,当原料气H₂S体积分数为227 μL/L,温度25 ℃,气体流量75 mL/min时,穿透硫容和饱和硫容达0.151和0.190 mmol/g,且吸附剂可再生利用。SBA-15表面嫁接氨基并浸渍金属改性的手段不仅提高了吸附容量,同时提高了分子筛的稳定性。     

一种合成六方板状Zr-Ce-SBA-15介孔材料的新方法

以P123为模板剂, 正硅酸乙酯为硅源, 氯化氧锆和硝酸亚铈为无机前驱盐, 在不外加无机酸的条件下, 利用无机前驱盐自身水解产生的弱酸性环境, 通过水热合成路线一步合成了具有大的径轴比、短孔道、六方板状形貌的Zr-Ce-SBA-15介孔材料. 利用粉末X射线衍射(XRD)、透射电子显微镜(TEM)、扫描电子显微镜(SEM)、电感耦合等离子体原子发射光谱(ICP-AES)和氮气吸附等手段对所合成的样品进行了表征. 结果表明, 合成的材料具有类似于SBA-15的二维六方介孔结构, 孔径、孔容和比表面积分别为5.6 nm, 0.96 cm3/g和776 m2/g. 与常规SBA-15相比, 这种短孔道、大径轴比的六方板状介孔材料在吸附、分离及催化等领域中能更有效地促进分子的扩散传递.     

担载钒氧化物催化剂对丙烷选择氧化性能

用等体积浸渍法制备了SBA-15担载的钒基氧化物催化剂,使用X射线衍射（XRD）分析、氮气吸附、紫外激光拉曼、傅里叶变换红外（FTIR）光谱和紫外-可见漫反射（UV-Vis DRS）光谱对催化剂的结构进行了表征,并评价了催化剂对丙烷选择氧化的活性与选择性.实验结果表明SBA-15载体对丙烷选择氧化的活性优于常规的SiO₂载体.SBA-15担载的低载量催化剂是高分散的催化剂体系,在低钒载量（n（V）/n（Si）<2.5%）时,催化剂具有规则的六方介孔结构.低钒载量（n（V）/n（Si）<0.1%）时,隔离四配位的钒氧化物是丙烷选择氧化生成醛类化合物的活性物种;高钒载量（n（V）/n（Si）>2.5%）时,聚合六配位的钒氧化物和微晶钒氧化物是丙烷脱氢或深度氧化的活性物种.     

高度有序介孔氧化硅材料SBA-15：高浓度氨基官能化及氨基及氨基团的可利用性

采用简单的方法合成高浓度氨基修饰的高度有序氧化硅材料并深入研究氨基官能化材料的孔结构以及氨基的存在状态和可利用性。结果表明,氨基基团共价连接到SBA-15的孔表面,即使初始合成体系中的APTES（氨丙基三乙氧基硅烷）浓度高达30mol%时材料依然保持高度的有序性。合成体系中APTES浓度为20％的样品还保持良好的介孔结构,比表面积为680 m²·g^-1,孔容为0.89 cm³·g^-1,此介孔结构中的氨基官能团对镍离子表现出很强的亲和力,Ni²⁺的吸附量高达1.88 mmol·g^-1,相比之下未官能化的SBA-15对Ni²⁺没有吸附作用。当初始合成体系中APTES的浓度进一步增大到30％时,修饰到介孔氧化硅材料的氨基含量也随之增大,但由于材料的孔隙度急剧降低,这些氨基的可利用性也降低。     

Bilirubin adsorption on amine/methyl bifunctionalized SBA-15 with platelet morphology

To remove bilirubin from human plasma, amine/methyl bifunctionalized SBA-15 materials were directly synthesized from the co-condensation of 3-aminopropylmethyldiethoxysilane and tetraethoxysilane with an amphiphilic block copolymer P123 as template. XRD, N(2) sorption analysis, FTIR and (29)Si MAS NMR were used to identify their well-ordered mesostructure and the grafting of amine and methyl groups on the surface of as-synthesized materials. Both SEM and TEM indicated that the bifunctionalized SBA-15 possessed platelet morphology. This might be attributed to the charge repulsion brought by protonated amine groups and the diminution of hydroxyl groups on the end of silicate-micelles, which passivated the end-to-end anchoring of silicate-micelles along the longitudinal axis. Such a material was investigated as the adsorbent for selective bilirubin removal from human plasma, which showed a high bilirubin clearance of 51.4% within 1.5 h with a little amount of albumin adsorption. The results of hemolysis assay suggested that the bifunctionalized SBA-15 caused serious hemolysis of red blood cells. However, in practical application, plasma separation technique could avoid direct contact between the adsorbent and red blood cells. The further hemeolysis assay proved that the plasma after contacting with the bifunctionalized SBA-15 could not lead to the hemolysis of red blood cells. Thus, the bifunctionalized SBA-15 is expected to be a potential candidate as a clinical hemoperfusion material.     

Salt-induced formation of uniform fiberlike SBA-15 mesoporous silica particles and application to toluene adsorption

Long, homogeneous fiberlike SBA-15 mesoporous silica particles are prepared by fine adjustment of three reaction conditions--stirring temperature, stirring time, and amount of inorganic salt added--using Pluronic P123 and TEOS under acidic conditions. The addition of NaCl along with a short stirring time played an important role in controlling the morphology and pore characteristics. Dynamic adsorption performance for gaseous toluene was systematically evaluated using four types of materials with different morphologies and pore characteristics synthesized with the addition of a different amount of NaCl. Breakthrough curves showed that the longer the fiberlike structure, the longer the breakthrough time. Furthermore, it was found from the breakthrough times and the total amounts adsorbed that long particles with high microporosity offer effective adsorption performance and should be useful in applications such as toluene adsorption.     

Functionalized SBA-15 materials as carriers for controlled drug delivery: influence of surface properties on matrix-drug interactions

Mesoporous SBA-15 materials were functionalized with amine groups through postsynthesis and one-pot synthesis, and the resulting functionalized materials were investigated as matrixes for controlled drug delivery. The materials were characterized by FTIR, N(2) adsorption/desorption analysis, zeta potential measurement, XRD, XPS, and TEM. Ibuprofen (IBU) and bovine serum albumin (BSA) were selected as model drugs and loaded onto the unmodified and functionalized SBA-15. It was revealed that the adsorption capacities and release behaviors of these model drugs were highly dependent on the different surface properties of SBA-15 materials. The release rate of IBU from SBA-15 functionalized by postsynthesis is found to be effectively controlled as compared to that from pure SBA-15 and SBA-15 functionalized by one-pot synthesis due to the ionic interaction between carboxyl groups in IBU and amine groups on the surface of SBA-15. However, SBA-15 functionalized by one-pot synthesis is found to be more favorable for the adsorption and release of BSA due to the balance of electrostatic interaction and hydrophilic interaction between BSA and the functionalized SBA-15 matrix.     

Effect of pH on the structural characteristics of in situ synthesized Ni-incorporated SBA-15 magnetic composites

Ni-incorporated SBA-15 magnetic composites were two-stage hydrothermal synthesized from initial strong acidic media through a pH-adjusting method. The structure, morphology, surface area and pore size distribution of the samples were systematically characterized by using XRD, FT-IR, SEM, TEM and N₂ physical adsorption techniques. It was found that, when pH was adjusted to 7, the obtained sample still could exhibit hexagonal mesostructure, very similar to that of the pristine SBA-15 except for a slightly reduced long-range ordering and surface area. However, an increase in the unit cell and wall thickness of the samples suggested the more Ni species were incorporated into the framework of SBA-15. A further increase in pH to 9 produced deterioration of long-range ordering of the sample, possibly resulting from the blocking of some mesopores. Thus, the pH-adjusting method played an important role on the structure of Ni–SBA-15 composites. Measurements taken with increasing applied field revealed the samples having superparamagnetic behaviors. Furthermore, the saturation magnetization values were increased with the more Ni species transforming into magnetic nanoparticles by the increasing pH.     

New attempt at directly generating superbasicity on mesoporous silica SBA-15

Direct generation of superbasicity on mesoporous silica SBA-15 was realized by tailoring the host-guest interaction, and calcium species were selected as the guest in modifying SBA-15. The results show that calcium species could be homogeneously distributed on the surface of SBA-15. Because of the host-guest interaction, the decomposition of the supported calcium nitrate was apparently easier than the bulk one. Surprisingly, the calcium nitrates modified SBA-15 (CaNS) samples exhibited superbasicity with good preservation of the mesostructure after activation, differing from the potassium nitrate loaded SBA-15 samples that displayed weak basicity with collapsed mesostructure. The present superbasic CaNS materials also possess good water resistance and high surface areas, up to 429 m(2) g(-1), which is promising for their potential applications in adsorption and catalysis. Further investigation concerning the roles played by the guest in basicity formation on SBA-15 was conducted. The samples modified by Group 2 metal nitrates showed strong basicity with base strength (H-) of 22.5-27.0 and good preservation of mesostructure. In contrast, loading Group 1 metal nitrates on SBA-15 produced samples with weak basicity ( H-=9.3-15.0) and collapsed mesostructure after activation. Such differences can be related to the interaction between the resulting metal oxide and the silica support, as well as the mobility of the cations in the metal oxide.     

Synthesis and lysozyme adsorption of rod-like large-pore periodic mesoporous organosilica

Highly ordered rod-like large-pore periodic mesoporous organosilica (PMO) was successfully synthesized at low acid concentration with the assistance of inorganic salt using triblock copolymer P123 as a template. The roles of inorganic salt and acidity in the production of highly ordered mesostructure and the morphology control of PMOs were investigated. It was found that the inorganic salt can significantly widen the range of the synthesis parameters to produce highly ordered 2D hexagonal pore structure of p6mm symmetry. However, the uniform rod-like PMOs can only be synthesized in a narrow range of acid and salt concentrations, which were sensitive to induction time. The adsorption of lysozyme on PMO was studied at different pH values in comparison with adsorption on pure silica material under controlled morphology and pore structure. It was found that the adsorption capacity of lysozyme on the PMO was lower than that on pure SBA-15 silica material and the adsorption amounts are larger at pH 9.6 than at 7.0 for both materials. The results show that the electrostatic interaction between lysozyme and PMO/SBA-15 surface is more dominant than the hydrophobic forces and the interaction of neighboring lysozyme molecules also plays an important role.     

Controlled drug release from bifunctionalized mesoporous silica

Serial of trimethylsilyl-carboxyl bifunctionalized SBA-15 (TMS/COOH/SBA-15) have been studied as carriers for controlled release of drug famotidine (Famo). To load Famo with large capacity, SBA-15 with high content of carboxyl groups was successfully synthesized by one-pot synthesis under the assistance of KCl. The mesostructure of carboxyl functionalized SBA-15 (COOH/SBA-15) could still be kept even though the content of carboxyl groups was up to 57.2%. Increasing carboxyl content could effectively enhance the loading capacity of Famo. Compared with pure SBA-15, into which Famo could be hardly adsorbed, the largest drug loading capacity of COOH/SBA-15 could achieve 396.9 mg/g. The release of Famo from mesoporous silica was studied in simulated intestine fluid (SIF, pH=7.4). For COOH/SBA-15, the release rate of Famo decreased with narrowing pore size. After grafting TMS groups on the surface of COOH/SBA-15 with hexamethyldisilazane, the release of Famo was greatly delayed with the increasing content of TMS groups.     

Amine-functionalized SBA-15 with uniform morphology and well-defined mesostructure for highly sensitive chemosensors to detect formaldehyde vapor

Amine-functionalized SBA-15 with uniform morphology and well-defined mesostructure was prepared using a postgrafting route. The morphology, mesostructure, and functionality of the materials were characterized by scanning electron microscopy, transmission electron microscopy, small-angle X-ray scattering, nitrogen adsorption-desorption, Fourier transform infrared spectroscopy, and solid-state nuclear magnetic resonance spectroscopy techniques. The results show that hexagonal lamelliform SBA-15 with a uniform particle size and short vertical channels plays two significant roles in uniformly dispersing amine-functionalizing groups and effectively adjusting the loadings of the functional groups within the mesopore channels. To confirm the potential application of the hybrids in gas sensors, using amine-functionalized SBA-15 as a sensing material and a quartz crystal microbalance as a transducer, a parts per billion level formaldehyde sensor with high sensitivity (response time about 11 s, recovery time about 15 s) and good chemoselectivity was achieved. This material holds great potential in the area of rapid, sensitive, and highly convenient formaldehyde detection.     

氨基功能化短孔道有序介孔材料H_2N-Zr-Ce-SBA-15的合成及吸附性能

以pluronic(P123)为模板剂,正硅酸乙酯(TEOS)为硅源,氯化氧锆和硝酸亚铈为无机前驱盐,N-(2-氨乙基)-3-氨丙基三甲氧基硅烷(AAPTS)为硅烷化试剂,采用后接枝法合成了氨基功能化六方板状短孔道有序介孔材料H2N-Zr-Ce-SBA-15(H2N-ZCS).采用小角X射线衍射(LXRD)、傅里叶变换红外(FTIR)光谱、透射电子显微镜(TEM)、扫描电子显微镜(SEM)、热重分析、N2吸附/脱附等手段对H2N-ZCS进行了表征.结果表明AAPTS成功地嫁接到有序介孔材料上,H2N-ZCS仍保持了类似于传统SBA-15高度有序的二维六方相介孔结构,且孔道方向垂直于该六方板面.对阴离子染料酸性品红吸附实验表明,H2N-ZCS比H2N-SBA-15具有较强的吸附能力.这种功能化短孔道、大径轴比的六方板状介孔材料在吸附、分离及催化等领域中能更有效地促进分子的扩散传递.     

Synthesis of carboxyl-modified rod-like SBA-15 by rapid co-condensation

Carboxyl-modified SBA-15 rod-like mesoporous materials have been synthesized by a facile rapid co-condensation of tetraethylorthosilicate (TEOS) and 2-cyanoethyltriethoxysilane (CTES), followed by hydrolysis of cyanide groups in sulfuric acid. The concentration of carboxylic groups was varied by changing the silica source ratio of CTES/TEOS from 0.05 to 0.3. X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) showed that the uniform ordered mesoporous structure and rod-like morphology of SBA-15 have been preserved even at the high concentration of carboxylic groups employed. Characterization by Fourier transformed infrared spectroscopy (FTIR), solid-state NMR investigation indicated that carboxylic groups have been successfully grafted onto the surface of SBA-15 through siloxane bonds [(O(3))SiCH(2)CH(2)COOH. The negative charges of the modified SBA-15 materials were enhanced by the presence of the carboxylic groups on the surface. The capacity of lysozyme adsorption of the modified SBA-15 materials were found to be significantly improved as compared with pure silica SBA-15. The maximum amount of lysozyme adsorption on carboxyl-modified was increased with the pH of solution increased from 5.5 to 9.0.