Ti-HMS合成、表征及其催化氧化性能研究

以有机金属二氯二茂钛为钛源,六方介孔二氧化硅分子筛(HMS)为载体,采用嫁接法合成了含钛量(mol)分别为2.8%、3.8%和4.8%的Ti-HMS,HMS合成原料组成中H2O/EtOH(v/v)分别为0.5、1、2、5、9.合成材料用X射线粉末衍射(XRD)、N2吸附-脱附等温线、漫反射紫外可见光谱(UV-VIS)进行了表征,并考察了它们以叔丁基过氧化物(TBHP)为氧化剂在对叔丁基甲苯液相氧化中的催化性能.结果表明,表面钛嫁接后的HMS介孔结构有所损失,比表面积和孔体积减少.载体HMS合成原料中的H2O/EtOH(v/v)影响介孔织构和钛的配位环境.UV-VIS资料表明,H2O/EtOH(v/v)=0.5和9时不利于钛着床于分子筛骨架,H2O/EtOH(v/v)=1、2和5的HMS适合作为嫁接钛的载体.催化剂的活性主要受四配位Ti、介孔织构的影响.钛嫁接的HMS在氧化反应中表现出较好的催化活性,载钛量为4.8%Ti、H2O/EtOH(v/v)=1的Ti-HMS显示最好催化活性,对叔丁基甲苯转化率为21.8%.     

HMS介孔分子筛表征及吸附铅(Ⅱ)离子性能

通过水热法制备了HMS介孔分子筛,采用X射线衍射(XRD)、氮气吸附、扫描电镜(SEM)、透射电镜(TEM)等手段表征了其结构性能,考察了其对水溶液中二价铅离子的吸附性能。结果表明:合成的HMS分子筛具有典型的介孔材料特征,比表面积为790.7 m2/g,最可几孔径为3.7 nm,平均孔径为4.6 nm,孔容为0.91 m L/g;合成的HMS介孔分子筛对二价铅离子具有良好的吸附性能。在铅离子质量浓度为100 mg/L的水样中,吸附剂投加量为8 g/L,在p H为7、吸附时间为40 min条件下,HMS介孔分子筛对二价铅离子的吸附率达到96.22%。吸附符合Langmuir等温方程所描述的规律,而对Freundlich方程符合程度较低。     

有序介孔SnO2-聚合物复合材料的合成与表征

以水合四氯化锡为锡源,酚醛树脂为碳源,三嵌段共聚物F127为结构导向剂,通过溶剂挥发诱导自组装技术一步法合成有序介孔SnO2-聚合物复合材料.XRD、TEM和氮气吸附等温线等表征结果表明介孔SnO2-聚合物复合材料具有有序的二维六方结构,高比表面积(310～530m2/g),大孔容(0.28～0.47 cm3/g)和均...     

含铝介孔材料的合成研究进展

含铝介孔材料在催化、吸附与分离、高分子材料合成和环境领域有着广泛的应用,本文介绍了目前合成介孔氧化铝、介孔磷酸铝、含铝介孔二氧化硅的研究状况,包括合成介孔氧化铝的模板剂机理与路径,合成介孔磷酸铝的共轭配对理论,以及利用浸渍嫁接和直接合成的方法制备含铝介孔二氧化硅。     

一种聚乙二醇单甲醚修饰的介孔二氧化硅纳米颗粒及其制备方法和用途

正本发明涉及一种聚乙二醇单甲醚修饰的介孔二氧化硅纳米颗粒及其制备方法和用途,属于医药技术领域。聚乙二醇单甲醚修饰的介孔二氧化硅纳米颗粒的制法为:(1)聚乙二醇单甲醚丙烯酸酯-二巯基化合物的制备;(2)巯丙基修饰的介孔二氧化硅纳米颗粒的制备;(3)聚乙二醇单甲醚修饰的介孔二氧化硅纳米颗粒的制备。其产品的平粒径为50~     

零价钴作为骨架的介孔钴-氧化硅的制备

在室温下采用溶胶凝胶法合成Co~(2+)掺杂的介孔二氧化硅,然后在氢气气氛下还原,得到介孔钴-氧化硅复合材料,并表征了复合材料的结构.还原之后的介孔材料表现出良好的介孔特征,孔径分布均一;还原温度高达650℃左右,在氧化钴-氧化硅复合材料中钴可能是以类似于硅酸钴的形式存在的;在还原制得的钴-氧化硅复合材料中,观察不到钴的微小晶粒的存在,表明钴可能是以金属原子或极其微小的晶粒的形态镶嵌在介孔复合材料中.     

介孔二氧化硅微球的制备及其形成机理探究

以硅酸钠为硅源,硫酸为酸化剂,聚乙二醇为模板剂,利用均相反应器水热法制备了介孔二氧化硅微球.考察硅酸钠、硫酸、聚乙二醇的浓度及聚乙二醇聚合度对产物形貌和材料表面特性的影响,研究了介孔二氧化硅微球的形成机理.运用XRD,FT-IR,XRF,SEM,BET等手段对产品进行表征.从表征结果可以看出,所制备的介孔二氧化硅微球球形度良好,粒径分布比较均匀,纯度高,比表面在92～577 m2/g、孔体积在0.141～1.141 cm3/g范围内可调控.通过TEM对聚乙二醇胶束的研究得到介孔二氧化硅微球的形成机理.     

HMS介孔分子筛合成及其在丙烷脱氢制丙烯反应中的应用

分别以正硅酸乙酯和伯胺表面活性剂为原料和模板剂成功制备HMS介孔分子筛，经负载活性组分后得到Pt-Sn/HMS催化剂并将其应用于丙烷脱氢制丙烯反应。探究合成过程中伯胺表面活性剂碳链长度及水和乙醇的比例对HMS介孔分子筛孔结构的影响。XRD和N₂吸附-脱附等分析结果表明，模板剂链长增长时，介孔分子筛孔径、孔壁厚、比表面积及孔容均增大。适当的水/乙醇比例有利于获得更大比表面积和孔体积的介孔分子筛，并表现出更有序的介孔结构。丙烷脱氢制丙烯反应评价和热分析等表征结果表明，HMS介孔分子筛孔道特征直接影响Pt-Sn/HMS催化剂的催化性能。使用孔体积且比表面积较大的HMS样品作为载体制备的脱氢催化剂在丙烷脱氢反应中表现出优异的催化活性。性能最优的Pt-Sn/HMS-0.60-16催化剂上，平均丙烷转化率达到46.5%,平均丙烯选择性为94.1%,反应24 h后积炭量仅为质量分数3.4%。     

介孔材料HMS的改性及在催化反应中的应用

六方介孔硅HMS介孔分子筛具有合成方法简单、条件温和、较大孔径、高比表面、水热稳定性高、很强的吸附和扩散能力和丰富的表面羟基等优良性能,可作为载体或催化剂应用于许多有机化学反应中,特别是应用在大分子尺寸的有机反应中。详细地综述了近10年来HMS介孔材料通过单一金属、复合金属和酸碱改性及其改性后HMS在催化反应中的应用,并对其今后的研究方向进行了展望。     

离子液体中AgCl/介孔二氧化硅复合材料的制备及光催化性能

以硅烷化咪唑基离子液体为结构导向剂和反应物,通过有机-无机自组装方法合成了离子液体掺杂的介孔二氧化硅,并利用该材料末端的卤离子,制备了分散性较好的AgCl/介孔二氧化硅复合材料。采用FT-IR、XRD、UV-vis DRS、BET,TEM等手段对所合成材料的组成、结构和性质进行了表征,并进一步研究了该催化剂对染料的光降解效果。结果表明,在一定条件下,材料AgCl/介孔二氧化硅对甲基橙和靛红具有良好的光催化降解效果。     

铁改性HMS催化氧化苯甲醇合成苯甲醛

以十二胺为模板在中性条件下合成了Fe-HMS介孔分子筛,研究了不同硅铁比Fe-HMS对苯甲醇催化氧化反应的影响。利用XRD、BET、SEM和H₂-TPR等方法对合成的催化剂进行了表征。考察了Fe-HMS对苯甲醇氧化反应的影响。结果表明,Fe³⁺ 离子进入了分子筛骨架,Fe-HMS分子筛具有均一的蠕虫状介孔结构。焙烧后的Fe-HMS中Fe³⁺ 主要以Fe₂O₃形式存在于骨架中。对苯甲醇液相选择性氧化反应,Fe-HMS分子筛的催化活性高于Fe-SiO₂。在85℃、Si/Fe摩尔比为25∶1、醇/双氧水摩尔比为1∶2、催化剂含量为4%、反应时间4 h条件下,苯甲醇的转化率和苯甲醛的选择性分别为65.1%和74.6%。     

Adsorption of Hydroxypropyl Methyl Cellulose in an Aqueous System Containing Multicomponent Oxide Particles

The adsorption behavior of a hydroxypropyl methyl cellulose (HPMC) polymer in aqueous suspensions of alumina, silica, kaolin, and talc powders, two-component combinations, and one three-component combination was determined. Powders were well characterized by chemical analysis, XRD, DRIFT, SEM, particle size, surface area, and density analyses. The zeta-potential of each powder in aqueous suspension was determined over a range of pH to determine particle charging and the isoelectric point for each material. Alumina and silica powders having heavily hydroxylated surfaces were observed not to adsorb the HPMC polymer over a range of pH. The layer-type minerals talc, which was noticeably hydrophobic, and kaolin, which had differently hydrated basal planes, adsorbed the HPMC polymer but in different amounts per unit of surface area. In the two-component systems, HPMC polymer adsorption for systems of dispersed particles of like electrical charge (kaolin + silica, talc + silica or alumina, and kaolin + talc) was proportionate to the sum of the fraction x specific surface area x adsorption capacity for each particle type. In systems where particles had an opposite electrical charge (kaolin + alumina, kaolin + talc + alumina), the HPMC polymer adsorption was significantly lower than that calculated for a dispersed system. SEM analysis showed very fine, nonadsorbing alumina particles predominantly on the faces of the adsorbing kaolin particles that apparently masked polymer adsorption. Results suggested a hydrophobic mechanism for the HPMC polymer adsorption and adsorption on only one face of the kaolin particles.     

Covalent grafting of polyacrylamide onto mesoporous MCM-41 silica via free radical polymerization

MCM-41 mesoporous silicas were covalently modified with polyacrylamide (PAAm) by a novel grafting strategy. The effect of various parameters such as monomer concentration, reaction time, and temperature on the content of PAAm onto MCM-41 silicas were studied. Modified silicas were characterized by X-ray diffraction (XRD), infrared spectroscopy, FT-IR, thermogravimetric analysis, nitrogen adsorption–desorption analyses, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy which confirmed the grafting process. According to XRD, SEM and TEM results, PAAm-modified MCM-41 silica did not show changes in its morphology and mesostructure by comparing with pristine MCM-41. Nitrogen adsorption–desorption studies showed that the attaching of PAAm onto MCM-41 silica decreased the values of pore size, pore volume and surface area.     

Hollow mesoporous silica spheres supported Ag and Ag–Au catalyzed reduction of 4-nitrobenzo-15-crown

Hollow mesoporous silica (HMS) spheres of size within the range 120–220 nm have been prepared using propanol–water solvent as template and cetyltrimethylammonium bromide (CTAB) as stabilizer. HMS supported silver and silver–gold catalysts were prepared by impregnating metal nanoparticles on HMS and were characterized by ultraviolet–visible spectroscopy (UV–vis), dynamic light scattering (DLS), optical microscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), inductive coupled plasma optical emission spectroscopy (ICP-OES) and N₂ adsorption–desorption. The reduction of 4-nitrobenzo-15-crown (4-NB-15-C) was compared using HMS supported silver and silver–gold nanocatalysts varying experimental parameters. Bimetallic Ag–Au/HMS nanocatalysts was found to be more active than monometallic Ag/HMS nanocatalyst.     

Pd/Ce-HMS介孔材料的结构和表面化学态

为了制备新型负载型Pd催化剂,采用合成后组装法和浸渍法室温合成了Pd/Ce-HMS介孔材料,产物用XRD、N2吸附、FTIR及XPS谱等手段进行表征。结果表明,Ce、Pd引入后六方介孔结构仍保持完好。产物的BET表面积为742.9 m2·g-1,孔容0.803 cm3·g-1,表面Pd、Ce物种主要以PdO2和CeO2形式存在。研究表明,Ce前驱体通过与孔表面富集的Si—OH基团作用而嵌入骨架或键合于孔表面,Pd担载时由于模板剂仍留在孔道中,因而没有造成孔道堵塞。     

Polyacrylamide-coated MCM-48 mesoporous silica spheres: synthesis,characterization and drug delivery study

Mesoporous type-MCM-48 silica was grafted with polyacrylamide (PAAm) by using an azo-type initiator. The effect of monomer and initiator concentrations, reaction time, and temperature were evaluated to determine the optimal grafting conditions. Functionalized MCM-48 silicas were characterized by X-ray diffraction (XRD), infrared spectroscopy, thermogravimetric analysis, nitrogen adsorption–desorption analyses, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) which confirmed the grafting process. According to XRD, SEM and TEM results, PAAm-modified MCM-48 silica did not show changes in its morphology and mesostructure by comparing with pristine MCM-48. Also, modified silicas were tested as delivery system using nalidixic acid as drug model. MCM-48-PAAm silicas were able to load more significant amounts of nalidixic acid than the unmodified MCM-48, and showed a sustained delivery behaviour, releasing about 80% of drug.     

掺杂Fe／Ti—HMS纳米光催化剂的合成与表征

在室温条件下通过溶胶凝胶法，以正硅酸乙酯为硅源，硫酸钛为钛源，三氯化铁为铁源，中性十二胺为模板剂成功合成了DDA-HMS，HMS，Ti—HMS以及Fe／Ti-HMS分子筛。采用粉末X射线（XRD），（FT—IR）、电子扫描显微镜（SEM）等手段对样品进行了表征。结果表明，分子筛的XRD图谱在小角度区出现较强的特征衍射峰，材料具有一维六方中孔结构，表征证实了Fe、Ti同时嵌入了HMS的晶体骨架，具有良好的稳定性。     

Effect study of hexagonal mesoporous silica/polyaniline nanocomposite on the structural properties of polysulfone membranes and its heavy metal removal efficiency

New mixed matrix membranes of polysulfone were synthesized by different content of hexagonal mesoporous silica coated by polyaniline and used for nickel and lead ion removal. The membranes were characterized by FESEM, XRD, BET, TGA, and FTIR, and zeta potential measurements. The results showed that PANi/HMS particles enhanced the membrane porosity and permeability. These effects were explained according to an increase of the membrane hydrophilicity due to the formation of new functional groups during membrane casting. The results showed that metal ion rejection was performed by a filtration–adsorption mechanism, resulting in fixation of metal ions on the active sites of membranes.     

Interfacial region of poly(n-butyl acrylate)/silicon oxide

Poly(n-butyl acrylate) (PnBA) and silica nanoparticle composites were cast from toluene solutions and investigated via differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FT-IR), and X-ray diffraction (XRD) analysis. The results suggested that the composites contained amorphous bulk and interfacial regions. The mobility of side chains at the interfaces between PnBA and the silica nanoparticles differed from the mobility of side chains in bulk PnBA. FT-IR analysis showed that the difference in mobility was due to interactions between the carbonyl groups in PnBA and the silica surfaces. These results indicated that PnBA main chains near interfaces with silicon oxide were separated by a smaller distance than main chains in the bulk polymer.     

Investigation on preparation of carboxymethyl chitosan modified sodium ferric silicate and its adsorption properties

The layered material of sodium ferric silicate (SFS) has good adsorption properties for cationic dyes, but its stacking properties limit its application. The organic–inorganic composite assembled by macromolecular polymer and inorganic material can improve this situation. Carboxymethyl chitosan (CC) was loaded onto SFS, and the compound was characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscope (TEM), Brunauer–Emmett–Teller (BET), zero energy thermonuclear assembly (Zeta), and Fourier transform infrared spectroscopy (FT-IR). The results showed that CC was successfully supported in the layered structure of SFS, and the adsorption capacity of the composite for methylene blue (MB) was 729.67 mg g⁻¹. The adsorption process was described by pseudo second-order kinetics, Langmuir isothermal equation, and intraparticle diffusion. The adsorption process was endothermic and spontaneous, and the monomolecular adsorption was dominant.