含MEI结构单元的介孔Ti-HMS-1的合成、表征及催化氧化性能

采用TS-1前驱体作硅源和钛源,以十二胺为模板剂,在中性和室温条件下合成了介孔含钛分子筛Ti-HMS-1.采用XRD、TEM、低温N2吸附、FT-IR和UV-Vis等方法对合成的分子筛进行了表征;以苯乙烯的催化氧化反应为模型反应,考察了合成的Ti-HMS-1的催化氧化性能.结果表明,Ti-HMS-1具有"worm-like"介孔结构,但长程有序度较低,孔壁部分含有MFI的次级结构单元,在373K沸水中水煮50h后,Ti-HMS-1仍能较好地保持原有的介孔结构,表明Ti-HMS-1具有较高的水热稳定性.进入分子筛骨架的钛原子为催化剂的活性中心,对于苯乙烯氧化反应,具有较高的催化活性,对产物的选择性与Ti-HMS接近.     

磺酸基有序介孔炭的一步合成及其催化性能

采用一步法直接制备磺酸基有序介孔炭材料,利用FT-IR、酸量、XRD、TEM和BET等对其结构与形貌进行表征,以苯甲醛与原甲酸三甲酯的缩醛反应为模型反应,并考察其催化性能。结果表明,在原料酚醛树脂∶硫酸∶F127质量比为1∶2∶0.3,炭化温度为600℃时,所制磺酸基介孔炭呈有序结构、较大的比表面积和均匀的孔径。采用上述条件合成介孔炭材料作催化剂时,反应收率可达87.1%,明显高于相同条件下传统分子筛固体酸催化剂HY与未加入磺酸基的介孔炭材料的催化效果。     

载铂多级孔ZSM-5分子筛用于邻二甲苯的“吸附?催化燃烧”循环脱除

首先利用F127作为软模板,采用蒸汽辅助晶化法合成出具有一定介孔结构的多级孔ZSM-5分子筛,然后采用等体积浸渍法负载铂,成功制备了载铂的多级孔ZSM-5分子筛催化剂。利用X射线衍射(XRD)、氮气吸附等温线(N2 isotherm)、扫描电子显微镜(SEM)和透射电子显微镜(TEM)对制备的催化剂进行了表征,并将催化剂用于邻二甲苯的吸附和催化燃烧反应,最后考察了催化剂"吸附-催化燃烧"循环脱除邻二甲苯的性能。结果表明,与传统ZSM-5分子筛相比,多级孔ZSM-5分子筛结晶度略有下降,但是介孔度和孔体积明显提升。介孔结构与微孔结构并存,极大提升了多级孔ZSM-5分子筛对邻二甲苯的吸附能力,其饱和吸附量达到了传统ZSM-5分子筛的约8倍。此外,介孔结构的存在提高了铂的分散度,使得载铂多级孔ZSM-5分子筛具有最佳的催化燃烧邻二甲苯性能,三次"吸附?催化燃烧"循环使用后的吸附容量依然基本保持不变,并且在催化燃烧过程中无二次污染物生成,具有较高的吸附容量和循环使用稳定性。     

酸碱复合处理制备多级孔ZSM-5分子筛及其甲醇制汽油反应性能

以商业ZSM-5分子筛为原料, 分别采用碱处理和酸碱复合处理法制备了多级孔ZSM-5分子筛。利用XRD、FT-IR、SEM、TEM以及氮气吸-脱附等手段对样品进行了表征, 并评价了样品的MTG反应性能。结果表明: 利用单纯碱处理或酸碱复合处理商业ZSM-5分子筛均可制备晶体内富含介孔和大孔的多级孔ZSM-5分子筛。与商业ZSM-5原料相比, 多级孔ZSM-5分子筛催化剂的介孔比表面积、介孔孔容以及酸性位“可接近性指数”等显著增加, 酸量明显减少, 酸强度降低。催化评价结果显示, 多级孔ZSM-5分子筛催化剂在大幅提高汽油产品收率、延长使用寿命的同时降低了芳烃收率。与碱处理样品相比, 酸处理能够进一步调节样品的酸性质和孔结构, 因此酸碱复合处理所得多级孔ZSM-5分子筛催化剂的物化性质和催化性能得以进一步提升。     

杂多酸固载催化剂的合成及窄分子量纤维素制备的研究

通过水热合成法制备MCM-41型介孔分子筛,采用浸渍法负载磷钨酸于MCM-41介孔分子筛中,煅烧得到新型HPW/MCM-41固载催化剂。利用傅里叶红外光谱(FT-IR)、X射线衍射(XRD)、热重分析(TG)和扫描电镜(SEM)对固载催化剂进行表征;考察催化剂对棉纤维催化降解反应的性能。结果表明,新型HPW/MCM-41固载催化剂即持有了磷钨酸的Keggin结构,同时又保持了分子筛的完整介孔结构,具有催化、筛分双重性能。棉纤维催化降解反应数据显示,磷钨酸负载量、反应温度、催化剂用量、液固比及停留时间均影响HPW/MCM-41降解纤维素的性能。在单因素实验最佳反应条件下,棉纤维素降解产物的分子量分布较为均匀,降解产物的产率较优。     

载铂多级孔ZSM-5分子筛用于邻二甲苯的“吸附-催化燃烧”循环脱除

首先利用F127作为软模板, 采用蒸汽辅助晶化法合成出具有一定介孔结构的多级孔ZSM-5分子筛, 然后采用等体积浸渍法负载铂, 成功制备了载铂的多级孔ZSM-5分子筛催化剂。利用X射线衍射(XRD)、氮气吸附等温线(N₂ isotherm)、扫描电子显微镜(SEM)和透射电子显微镜(TEM)对制备的催化剂进行了表征, 并将催化剂用于邻二甲苯的吸附和催化燃烧反应, 最后考察了催化剂“吸附-催化燃烧”循环脱除邻二甲苯的性能。结果表明, 与传统ZSM-5分子筛相比, 多级孔ZSM-5分子筛结晶度略有下降, 但是介孔度和孔体积明显提升。介孔结构与微孔结构并存, 极大提升了多级孔ZSM-5分子筛对邻二甲苯的吸附能力, 其饱和吸附量达到了传统ZSM-5分子筛的约8倍。此外, 介孔结构的存在提高了铂的分散度, 使得载铂多级孔ZSM-5分子筛具有最佳的催化燃烧邻二甲苯性能, 三次“吸附-催化燃烧”循环使用后的吸附容量依然基本保持不变, 并且在催化燃烧过程中无二次污染物生成, 具有较高的吸附容量和循环使用稳定性。     

含MFI结构单元的介孔Ti-HMS-1的合成、表征及催化氧化性能

采用TS-1前驱体作硅源和钛源,以十二胺为模板剂,在中性和室温条件下合成了介孔含钛分子筛Ti-HMS.1.采用XRD、TEM、低温N2吸附、FT-IR和UV-Vis等方法对合成的分子筛进行了表征;以苯乙烯的催化氧化反应为模型反应,考察了合成的Ti-HMS-1的催化氧化性能.结果表明,Ti-HMS-1具有“worm-like”介孔结构,但长程有序度较低,孔壁部分含有MFI的次级结构单元,在373K沸水中水煮50h后,Ti-HMS-1仍能较好地保持原有的介孔结构,表明Ti-HMS-1具有较高的水热稳定性.进入分子筛骨架的钛原子为催化剂的活性中心,对于苯乙烯氧化反应,具有较高的催化活性,对产物的选择性与Ti-HMS接近。     

功能化介孔氧化铝材料的制备及应用进展

介孔氧化铝因其在催化、吸附等领域具有巨大的应用前景,而受到国内外研究学者的广泛关注。随着工业化生产要求的不断提高,普通介孔氧化铝的使用逐渐受到限制,制备高性能的功能化介孔氧化铝材料将具有重大意义。功能化介孔氧化铝材料具有较高的催化活性、较强的机械和水热稳定性,不仅在催化、吸附领域受到极大重视,而且延伸到光学、医学等重要领域。综述了功能化介孔氧化铝材料的主要制备方法,包括原位合成法和浸渍法,并对两种方法存在的优缺点进行了比较。同时详细介绍了功能化介孔氧化铝材料的种类以及在催化、吸附分离和其它领域的应用,并展望了功能化介孔氧化铝材料的发展及应用前景。     

介孔材料在生物柴油合成中的应用

生物柴油是一种绿色可再生能源,一般是通过酸或碱催化酯化或酯交换反应来制备。综述了介孔金属氧化物、介孔分子筛及介孔磷酸盐等不同类型介孔材料催化剂用于制备生物柴油的研究进展,并对制备生物柴油的介孔催化剂研究方向进行展望。     

纳米介孔分子筛的合成、表征与催化性能的研究

以硅酸钠为硅源、偏铝酸钠为铝源、十六烷基三甲基溴化铵为模板剂,两步水热法合成出了有序性好、热稳定性与水热稳定性高的介孔分子筛.XRD、AFM、TG、RT-IR、BET比表面和孔径测定以及热稳定性和水热稳定性研究表明:制得了粒径为30～50nm的纳米级介孔分子筛,并且所制备介孔分子筛的比表面积大于800m2/g;在1123K以上热稳定性好;100℃水热处理10天后有序性、孔径和比表面都没有明显的变化.负载Pt样品对苯加氢反应的催化性能研究表明,反应温度250℃、3.0MPa下,载Pt样品的苯加氢活性和选择性都接近100%,连续反应30h催化活性没有明显的降低.     

Removal of patulin from aqueous solutions by propylthiol functionalized SBA-15

Propylthiol functionalized SBA-15 silica was investigated to detoxify aqueous solutions contaminated with the regulated mycotoxin patulin. Micelle templated silicas with a specific pore size were synthetically modified to possess propylthiol groups, a functional group known to form Michael reaction products with the conjugated double bond system of patulin. BET surface area analysis indicated the propylthiol functionalized SBA-15 possesses channels with the pore size of 5.4 nm and a surface area of 345 m(2)g(-1). Elemental analysis indicates the silicon/sulfur ratio to be 10:1, inferring one propylthiol substituent for every ten silica residues. The propylthiol modified SBA-15 was effective at significantly reducing high levels of patulin from aqueous solutions (pH 7.0) in batch sorption assays at room temperature. The material was less effective at lower pH; however heating low pH solutions and apple juice to 60 °C in the presence of propylthiol functionalized SBA-15 significantly reduced the levels of patulin in contaminated samples. Composite molecular models developed by semi-empirical PM3 and empirical force field methods support patulin permeation through the mesoporous channels of propylthiol functionalized SBA-15. Density functional study at the B3LYP/6-31G(d,p) level predicts the proposed patulin adducts formed by reaction with the thiol residues exhibit less electrophilic properties than patulin. It is demonstrated the use of propylthiol functionalized SBA-15 is a viable approach to reduce patulin levels in aqueous solutions, including contaminated apple juice.     

2-Mercaptothiazoline modified mesoporous silica for mercury removal from aqueous media

Mesoporous silicas (SBA-15 and MCM-41) have been functionalized by two different methods. Using the heterogeneous route the silylating agent, 3-chloropropyltriethoxysilane, was initially immobilized onto the mesoporous silica surface to give the chlorinated mesoporous silica Cl-SBA-15 or Cl-MCM-41. In a second step a multifunctionalized N, S donor compound (2-mercaptothiazoline, MTZ) was incorporated to obtain the functionalized silicas denoted as MTZ-SBA-15-Het or MTZ-MCM-41-Het. Using the homogeneous route, the functionalization was achieved via the one step reaction of the mesoporous silica with an organic ligand containing the chelating functions, to give the modified mesoporous silicas denoted as MTZ-SBA-15-Hom or MTZ-MCM-41-Hom. The functionalized mesoporous silicas were employed as adsorbents for the regeneration of aqueous solutions contaminated with Hg (II) at room temperature. SBA-15 and MCM-41 functionalized with MTZ by the homogeneous method present good mercury adsorption values (1.10 and 0.7mmolHg (II)/g of silica, respectively). This fact suggests a better applicability of such mesoporous silica supports to extract Hg (II) from aqueous solutions. In addition, it was observed the existence of a correlation between mercury adsorption with pore size and volume since, SBA-15 with lower areas and higher pore sizes functionalized with sterically demanding ligands, show better adsorption capacities than functionalized MCM-41.     

Amine and thiol functionalization of SBA-15 nanoparticles for highly efficient adsorption of sulforaphane

This study presents a novel material for highly efficient adsorption of sulforaphane based on SBA-15. The SBA-15 nanoparticles were synthesized using natural silica by hydrothermal method and functionalized with thiol and amine groups by the post-synthesis grafting procedure. All adsorbents were characterized by various techniques including BET, LAXRD, FT-IR, FE-SEM, and CHNS. The batch adsorption experiments revealed that the adsorption efficiency of SBA-15 for sulforaphane can be mainly influenced by the introduction of functional groups and the best adsorption performance was observed for amine-functionalized SBA-15 (SBA-15-NH₂) compared to pure SBA-15 and thiol-functionalized SBA-15 (SBA-15-SH) with the highest adsorption efficiency of about 97%. Preliminary adsorption studies of sulforaphane onto SBA-15-NH₂ were performed in aqueous solutions with different pH values and various organic solvents. Also, the effects of adsorbent dosage, contact time, and initial sulforaphane concentration on sulforaphane adsorption using SBA-15-NH₂ were studied. Langmuir and Redlich-Peterson isotherm models were the best-fitting models for the experimental data, followed by Temkin, Freundlich, and Dubinin-Radushkevich models. The adsorption process could be well described by the pseudo-first-order kinetic model based on kinetic parameters, correlation coefficient, and error functions. Meanwhile, the intra-particle diffusion model showed a multi-linear plot with three steps demonstrating slow diffusion into mesopores as a rate-limiting step.     

CdS纳米复合粒子的制备和光催化性能研究

为获得颗粒尺寸、形貌等比较规则的纳米CdS颗粒,通过逐层自组装技术和"两步法"相结合的方法在介孔分子筛SBA-15孔道内制备CdS纳米粒子,首先应用带电聚合物聚二烯丙基二甲基氯化铵(PDDA)、聚苯乙烯磺酸钠(PSS)将SBA-15孔道表面功能化,然后引入CdS前驱体Cd(CH3COO)2.2H2O,再将产物在H2S气氛中硫化得到最终产物SBA-15-PDDA-PSS-CdS。采用X射线衍射、N2吸附-脱附等手段进行测试表征,并将所制样品用于降解甲基橙来测试其光催化性能。结果表明:所制得的纳米CdS颗粒较小,分布均匀;纳米CdS在紫外光下对甲基橙具有良好的降解能力。     

Pd-porphyrin functionalized ionic liquid-modified mesoporous SBA-15: An efficient and recyclable catalyst for solvent-free Heck reaction

The Pd-porphyrin functionalized ionic liquid could be covalently anchored in the channels of mesoporous SBA-15 through ion-pair electrostatic interaction between imidazolium-cationic and Pd-porphyrin-anionic moieties. Such modified SBA-15 materials were prepared successfully via a post-synthesis (surface sol-gel polymerization) or a one-pot sol-gel procedure, which were characterized by powder X-ray diffraction, UV-visible spectroscopy, Fourier transform infrared spectroscopy, N₂ sorption, elemental analysis, and transmission electron microscopy. The modified SBA-15 materials are efficient and recyclable catalysts for cross-coupling of aryl iodides or activated aryl bromides with ethyl acrylate without activity loss and Pd leaching even after 9 runs.     

2-羟基-1-萘甲醛功能化SBA-15吸附剂的制备及其对Cr(III)的吸附性能

为去除水体中Cr(III)的污染, 本研究利用席夫碱反应原理制备了2-羟基-1-萘甲醛功能化SBA-15吸附剂(Q-SBA-15)。通过不同测试手段对所制备样品的形貌、孔道结构、元素组成和表面化学状态进行了系统表征。结果表明, SBA-15经2-羟基-1-萘甲醛修饰后, 其比表面积和孔径明显减小, 但表面形貌和晶体结构没有明显变化。为研究Q-SBA-15对Cr(III)的吸附性能, 详细分析了溶液pH和离子强度的影响, 以及吸附动力学、吸附等温线、吸附热力学和再生性能。结果表明, Q-SBA-15对Cr(III)吸附过程遵循准二级吸附动力学模型和Langmuir模型。当吸附温度为 40 ℃、pH为6、吸附时间为120 min时, Q-SBA-15对Cr(III)的吸附容量最大, 达到102.3 mg/g。Q-SBA-15对Cr(III)的吸附作用主要依靠其表面官能团与Cr(III)的配位螯合作用, 且为自发吸热过程。再生实验表明Q-SBA-15具有良好的重复使用性。该Q-SBA-15吸附剂在去除Cr(III)方面具有潜在的应用价值。     

巯基改性SBA-15的制备及其对Cr6+的吸附

环境中存在的重金属铬对人体健康有严重的危害, 本研究采用水热共缩聚法制备了一种对Cr ⁶⁺有较高吸附能力的介孔材料SBA-15-SH。经红外光谱证实, 通过使用改性硅源3-巯丙基三甲氧基硅烷, 对SBA-15成功实现了巯基改性。经扫描电子显微镜(SEM)和透射电子显微镜(TEM)观察, 所制备的材料呈棒状, 具有均匀的孔道结构, 孔径约为7 nm。将制备材料用于重金属Cr ⁶⁺的吸附, 研究了吸附时间、环境温度、Cr ⁶⁺溶液pH和初始浓度以及吸附剂用量对吸附剂吸附性能的影响。研究表明: 该材料吸附Cr ⁶⁺的平衡吸附时间约10 min, 吸附过程符合Langmuir方程与伪二级动力学模型。当Cr ⁶⁺溶液pH为4.0、吸附温度在25~45 ℃时, 介孔材料SBA-15-SH对Cr ⁶⁺吸附量最大, 达到6.85 mg/g。将本方法用于自来水和工业废水中Cr ⁶⁺的吸附, 回收率介于95%~105%之间。     

One-step synthesis,characterization and oxidative desulfurization of 12-tungstophosphoric heteropolyanions immobilized on amino functionalized SBA-15

Keggin-type 12-tungstophosphoric [PW₁₂O₄₀]^3? heteropolyanions were successfully immobilized onto mesoporous material surface of SBA-15 functionalized using the (3-aminopropyl)triethoxysilane (APTES) synthesized by one-pot co-condensation method, also called one-step synthesis. The synthesized PW^?-NH₃⁺-SBA-15 catalyst was characterized by XRD, N₂ adsorption–desorption, FT-IR, TGA, SEM, TEM, EDS, XPS methods. The results indicated that ordered hexagonal mesostructure for SBA-15 support was still maintained after being functionalized with amine groups, while the specific surface area of SBA-15 was decreased. The active species of phosphotungstic acid H₃PW₁₂O₄₀ (HPW) retained its Keggin structure of the heteropolyanions on the amine-modified SBA-15. The PW^?–⁺H₃N–SBA–15 catalyst exhibited a high catalytic activity for oxidative desulfurization process of sulfur-containing model fuel. The dibenzothiophene (DBT) conversion of almost 100% was achieved with reaction conditions of 40?mg of catalyst dosage, 2?mL of hydrogen peroxide, 90?°C of reaction temperature, and 120?min of reaction time.     

Room temperature ionic liquid (RTIL)-decorated mesoporous silica SBA-15 for papain immobilization: RTIL increased the amount and activity of immobilized enzyme

Mesoporous materials, especially functionalized ones, have become a promising carrier for enzyme immobilization. We synthesized room temperature ionic liquid-decorated mesoporous SBA-15 (RTIL-SBA-15) for papain immobilization. The results of powder XRD, IR and N₂ adsorption-desorption isotherms have confirmed that ionic liquid [Simim⁺][Cl⁻] was successfully grafted on the surface of SBA-15. As a consequence of the electrostatic attraction between the cation [Simim⁺] and the negatively charged papain, RTIL-SBA-15 had an advantage over SBA-15 when papain was immobilized at pH = 9.00. The kinetic study showed that the interaction between papain and the carrier was stronger after ionic liquid modification. In the casein hydrolysis, the papain immobilized on RTIL-SBA-15 showed a higher specific activity than that on SBA-15, implying that the ionic liquid [Simim⁺][Cl⁻] was beneficial to improve the activity of the immobilized papain. The optimum pH of the immobilized papain was shifted to higher than that of free enzyme.     

镧(Ⅲ)对SBA-15分子筛改性研究

借助水热法，利用三嵌段共聚物聚(1，2—亚乙基二醇)—嵌段—聚(丙二醇)—嵌段—聚(1，2—亚乙基二醇)为模板剂，正硅酸四乙酯为硅源，强酸性条件下制备了分子筛SBA—15．分别以水及水 乙醇为介质采用LaCl3溶液与煅烧的主体材料SBA—15分子筛固—液相交换法，制备了La—(SBA—15)复合材料．利用化学分析、粉末XRD、N2吸附技术、IR评价了制备方法的有效性及对SBA—15分子筛孔结构的影响．结果表明，镧已并入SBA—15分子筛中，SBA—15内表面上的硅羟基团是镧进入的主要位置，部分客体在分子筛孔道内．制得的材料La—(SBA—15)保持高度有序的介孔二维六角结构，不改变载体SBA—15的介SLSL道结构．此外，考察了La—(SBA—15)产物的发光现象。