用双表面活性剂为共模板合成中孔分子筛MCM-48

利用水热法以非离子表面活性剂聚乙二醇辛基苯基醚和阳离子表面活性剂十六烷基三甲基溴化铵为共模板合成了中孔分子筛MCM-48.实验中发现利用较强的范德华力和氢键,聚乙二醇辛基苯基醚可在很大程度上降低合成MCM-48所需阳离子表面活性剂的用量,且利于制备有序性好、骨架聚合度高、稳定性好的MCM-48.通过调节聚乙二醇辛基苯基醚与十六烷基三甲基溴化铵的比例,可得到不同物相结构的分子筛.     

Crucial factors affecting the physicochemical properties of sol–gel produced Fe3O4@SiO2–NH2 core–shell nanomaterials

Multifunctional nanomaterials with task-specific physicochemical properties, especially core?Cshell nanostructures with Fe₃O₄ core and NH₂-functional shells (Fe₃O₄@SiO₂?CNH₂), have been extensively investigated as high-performance adsorbents, catalysts and catalyst supports; and in most cases the controllable sol?Cgel technique is the choice for fabrication of this kind of widely applied materials. Herein, we demonstrated that mono-dispersed and spherical Fe₃O₄@SiO₂?CNH₂ nanomaterials with magnetic response core, NH₂-functional shell structure can be facilely prepared by co-condensation of TEOS with APTMS using a versatile sol?Cgel process. It was shown that the proper usage of APTMS and appropriate pre-hydrolysis time of TEOS were crucial and key steps for formation of highly uniform and desirable amino loading Fe₃O₄@SiO₂?CNH₂ materials. The TEOS pre-hydrolysis and the critical time (around 90?min) before the addition of APTMS prove to be vital for uniform structure evolution, while the appropriate concentration of APTMS (~2.28?mmol?L^?1 in our system) leads to well-dispersed materials with relatively high loading of amino functionality. The as-prepared Fe₃O₄@SiO₂?CNH₂ magnetic nanoparticles prepared under optimum conditions possessing superparamagnetic behavior, uniform core?Cshell structure (~200?nm in diameter), relatively large BET surface area (~138?m²/g) and high incorporation of amino-functionality (~2.90?wt?%).     

水热合成介观结构的ZnS纳米纤维

以Zn(Ac)₂和Na₂S为原料、EDTA为稳定剂、OA为结构导向模板,采用水热合成方法成功地制备了具有层状介观结构的ZnS纳米纤维;通过XRD, TEM, SEM, N₂-吸附/脱附以及紫外-可见漫反射等手段对所得的产物进了表征,并初步探讨了其形成机理.     

以沸石纳米簇构筑介孔AlMSU-2：与其他合成方法的比较研究及水热稳定性考察

采用含有β沸石基本结构单元的纳米簇为孔壁构造物合成了蠕虫状AlMSU-2介孔材料，并与通过直接合成和后处理嫁接途径所得的AlMSU-2进行了系统的比较研究。测试结果表明在适宜的酸度条件下，采用中性TX-100为中孔结构导向剂，以β沸石纳米簇为无机前驱物可便捷地将铝原子引入AlMSU-2骨架结构中，但目标产物并未显示出较后处理途径制得的AlMSU-2更为优越的水热稳定性。     

Ag+/MPTMS/PMHS-mediated two-step acid–base synthesis of hybrid materials with embedded nanosilver

A newly designed two-step acid–base sol–gel method for the synthesis of Ag-doped hybrid materials with tailored physicochemical properties is presented. In the proposed protocol, Ag⁺ is in situ reduced by Si–H bonds of polymethylhydrosiloxane (PMHS) in the absence of an additional reductant. Hydrolysis of the alkyloxysilane groups of tetraethoxysilane and PMHS or 3-mercaptopropyltrimethoxysilane (MPTMS) can be promoted by the release of H⁺ due to complexation between Ag⁺/Ag⁰ and thiol groups. Newly formed nanosilver can be fully stabilized by a sol–gel reaction and embedded parallel to the skeletons. The MPTMS dosage used during synthesis has a significant impact on the textural characteristics of the final products. The properties of as-prepared materials are characterized by Brunauer-Emmett-Teller analysis, transmission electron microscopy, and X-ray photoelectron spectroscopy. This study presents a novel method for the synthesis of Ag-doped hybrid materials using the synergetic effects of common organosilane precursors.     

Preparation of superhydrophobic materials for oil/water separation and oil absorption using PMHS–TEOS-derived xerogel and polystyrene

Fabrication of suerhydrophobic materials towards oil/water separation and oil absorption has been receiving great attention nowadays, due to the significant increase of industrial oily wastewater and frequent accident of oil spill. In most previous studies, the usage of expensive precursors restricted the wide applications of prepared superhydrophobic materials. In this work, superhydrophobic filter paper, fabric and polyester sponges were fabricated by dip-coating the mixed solution of polystyrene and xerogels, which were prepared with tetraethoxysilane and polymethylhydrosiloxane, based on previous work. The as-fabricated fabric can effectively separate oil and water mixtures and possesses excellent reusability; more significantly, the materials maintained its good hydrophobic and excellent oil/water separation capacity even after ten cycles. Interestingly enough, the stability was provided, as a result, the fabric still exhibited superhydrophobic after 100 abrasion times and showed high repellency towards many liquids with different pH values. Additionally, the coated polyester sponges can quickly absorb various oil and organic liquid, which will offer a practical application for the treatment of seawater or oily wastewater. By contrast, this experiment process is simple and avoided using costly fluoro-chemicals or complicated fabrication process.