分级结构介孔-大孔氧化铝的研究进展

介孔氧化铝材料自合成以来,因其在催化、吸附等领域的广泛应用受到了极大的关注。随着石油化工领域大分子反应不断增加,介孔氧化铝的使用逐渐受到限制,合成具有分级结构介孔-大孔氧化铝材料将具有重大意义。分级结构介孔-大孔氧化铝因其同时具有介孔和大孔孔道,不仅促进了客体分子在孔道内部的传送、减小扩散阻力,而且增大了孔道的比表面积,有助于改善吸附和分离效率、延长催化寿命,因此在吸附和催化方面具有广泛的应用前景。介绍了采用单模板法、双模板法和无模板法合成分级结构介孔-大孔氧化铝材料,并对材料在吸附和催化领域的应用进行探讨,最后对分级结构介孔-大孔氧化铝材料的发展趋势进行了展望。     

介孔硅基分子筛吸附去除挥发性有机化合物的研究进展

挥发性有机化合物(VOCs)的排放对生态环境和人体健康产生严重危害。作为VOCs处理的常用方法之一,吸附法因具有成本低、效率高且可回收和再利用等特点而受到广泛关注。介孔硅基分子筛具有高度有序的孔道结构、较大的比表面积和孔容以及孔道表面易于修饰等特点,十分适合作为VOCs的吸附材料,近年来引起研究者们的广泛关注。介孔分子筛中作为VOCs吸附剂的主要为M41S、SBA和HMS等硅基材料,研究表明,介孔硅基分子筛的吸附性能不仅与材料的孔道结构有关,还受分子筛的宏观形貌特征等因素的影响。对介孔分子筛进行引入微孔的结构改进,合成微-介复合结构材料,既能够提升吸附过程的扩散作用,又解决了分子筛孔结构单一的问题,能够达到提升材料吸附性能的同时增强其水热稳定性的目的。此外,就同一种分子筛的宏观形貌而言,其孔道结构越长,越有利于VOCs分子的扩散与吸附。然而,实际工业活动中的VOCs气体中往往会携带水分,由于纯介孔硅分子筛具有亲水性的特点,制约了其广泛应用。因此,近年来除探究介孔硅基分子筛的结构和形貌对VOCs吸附能力的影响外,研究者们主要对分子筛表面环境进行深入研究,通过接枝法和共缩合法等改性方式提升分子筛在潮湿条件下的吸附性能,并取得了长足的进展。本文归纳了近年来介孔硅基分子筛吸附脱除VOCs的研究成果与进展,分别对分子筛结构、形貌和表面环境等影响吸附性能的因素进行介绍,总结了吸附VOCs能力较强的介孔分子筛的特性,指出了吸附VOCs过程的局限性,重点讨论了疏水改性对分子筛吸附能力的提升,并对未来的研究工作进行了展望。     

软模板法合成介孔碳材料的研究与展望

介孔碳材料因其较高的比表面积,丰富的介观结构,高度有序的纳米孔道,已经引起了人们广泛的关注,因此在许多领域具有潜在的应用价值。软模板法合成介孔碳材料具有简单易行、成本低、结构可控等优点。目前采用最广泛的是溶剂挥发诱导自组装法和水热合成法,此文总结了这两种方法合成有序介孔碳材料的合成路线,阐述了其广泛的应用领域,并对有序介孔碳材料的合成与应用进行了展望。     

介孔材料的合成机理与应用

对近年来介孔材料的最新研究进展进行了综述.就介孔材料的主要合成机理,即液晶模板机理、电荷匹配机理、静电作用模型、棒状自组装模型和层状折皱模型等进行了简要介绍,对介孔材料在催化、吸附、纳米复合体系及其他领域的应用情况进行了总结,并对未来的发展趋势进行了展望.     

介孔材料在卷烟工业中的应用进展

介孔材料具有比表面积高、结构可调、水热稳定性好和独特的吸附性能,在烟草行业具有较好的应用前景。总结了介孔材料的分类、合成以及在卷烟中选择性吸附特定物质的应用及相应的吸附机理,展望了介孔材料目前在卷烟中应用的研究方向。     

有序介孔炭的模板合成进展

以MCM-41为代表的介孔分子筛具有孔道排列规则、孔径分布窄、比表面积高等特点，在催化、吸附、分离等领域具有广泛应用前景，尤其是以其为模板开展的纳米组装科学已成为目前材料研究的热点之一。在简要介绍硅基介孔分子筛的分类和合成机理的基础上，对国内外多孔炭模板合成的研究现状进行了述评，重点阐述了有序介孔炭模板合成的特点、合成工艺、模板类型、碳前驱体的种类及其在双电层电容器、催化、储能等方面的初步应用结果，并展望了有序介孔炭模板合成的发展趋势，指出模板成本的降低、工艺条件的简化和可控化将成为未来一段时期人们研究的重点。     

新型有序介孔材料在药物传递系统中的应用

根据近10年来有序介孔材料用于药物传递系统的研究报道,综述了几种新型介孔材料的合成方法,讨论分析了药物传递系统中孔径、孔道长度、形貌和功能基团修饰等影响因素,着重阐述和评价了影响有序介孔材料结构特征的合成工艺条件,以及这些有序介孔材料潜在的药学应用价值和急需解决的问题,旨在为新型有序介孔材料在药物传递系统中的应用提供参考.     

介孔炭材料及介孔炭/氧化硅复合材料对大分子有机污染物的吸附

介孔炭材料与活性炭相比具有较大的孔体积和孔径,高的比表面积以及规则的孔道结构,而介孔炭/氧化硅复合材料兼顾了活性炭与介孔材料的优点,因此在吸附大分子有机污染物方面有很好的应用前景。笔者综述了近年来介孔炭,负载/修饰后的介孔炭,介孔炭/氧化硅复合材料的制备和最新研究进展。在制备方面,根据其制备机理的不同可分为硬模板法和软模板法,制备出有序的介孔炭与介孔炭/氧化硅复合材料。在应用方面,重点介绍了介孔炭材料和介孔炭/氧化硅复合材料对大分子有机污染物的吸附性能。进而对介孔炭/氧化硅复合材料在吸附方面的应用进行了展望。     

介孔稀土氧化物的合成研究进展

介孔稀土氧化物由于在催化、光、电、磁等领域具有巨大应用潜力,已逐渐成为一个研究的热点.介绍了介孔材料的合成机理,较全面地综述了近年来合成介孔稀土氧化物的几种方法及最新研究进展.通过各种物理表征结果考察了合成条件对介孔材料的性质和形貌的影响,指出了目前介孔稀土氧化物制备方面存在的一些问题,对其应用前景进行了展望.     

二氧化钛介孔材料的合成研究

介孔二氧化钛特殊的结构和性能,使其在催化、吸附、分离等领域展现出广阔的应用前景.介绍了有序介孔材料的合成机理,综述了不同类型的表面活性剂在二氧化钛介孔材料合成中的应用和研究进展,指出了表面活性剂脱除的关键问题及解决方法.     

Immobilization of lysozyme onto pore-engineered mesoporous AISBA-15

In this research, hydrothermally stable mesoporous AISBA-15 materials have been used as adsorbents for systematic research on the lysozyme adsorption. Stability of the AISBA-15 adsorbents and the lysozyme molecules after the adsorption experiments for several days in aqueous solutions were confirmed by X-ray diffraction (XRD) measurement and FT-IR spectroscopy, respectively. The amount of the lysozyme adsorption can easily be controlled by the pore diameter and pore volume the mesoporous adsorbent, but an unreasonable effect of the surface area on the protein adsorption capacity was observed. The results of the effect of the pore diameter on the lysozyme adsorption suggest that the adsorption might partially be influenced by kinetically favorable edge-on type orientation on the confined mesopore. However, the final adsorption amount of the lysozyme can be well regenerated by models based on the side-on adsorption in dense packing. The present research also confirms the importance of appropriate "pore-engineering" for immobilization of bio-function on mesoporous materials.     

Ordered nanoporous polymer-carbon composites

Nanostructured organic materials, particularly those constructed with uniform nanopores, have been sought for a long time in materials science. There have been many successful reports on the synthesis of nanostructured organic materials using the so-called, 'supramolecular liquid crystal templating' route. Ordered nanoporous polymeric materials can also be synthesized through a polymerization route using colloidal or mesoporous silica templates. The organic pore structures constructed by these approaches, however, are lower in mechanical strength and resistance to chemical treatments than nanoporous inorganic, silica and carbon materials. Moreover, the synthesis of the organic materials is yet of limited success in the variation of pore sizes and structures, whereas a rich variety of hexagonal and cubic structures is available with tunable pore diameters in the case of the inorganic materials. Here we describe a synthesis strategy towards ordered nanoporous organic polymers, using mesoporous carbon as the retaining framework. The polymer-carbon composite nanoporous materials exhibit the same chemical properties of the organic polymers, whereas the stability of the pores against mechanical compression, thermal and chemical treatments is greatly enhanced. The synthesis strategy can be extended to various compositions of hydrophilic and hydrophobic organic polymers, with various pore diameters, connectivity and shapes. The resultant materials exhibiting surface properties of the polymers, as well as the electric conductivity of the carbon framework, could provide new possibilities for advanced applications. Furthermore, the synthesis strategy can be extended to other inorganic supports such as mesoporous silicas.     

Mesoporous Nanoarchitectures for Electrochemical Energy Conversion and Storage

Mesoporous materials have attracted considerable attention because of their distinctive properties, including high surface areas, large pore sizes, tunable pore structures, controllable chemical compositions, and abundant forms of composite materials. During the last decade, there has been increasing research interest in constructing advanced mesoporous nanomaterials possessing short and open channels with efficient mass diffusion capability and rich accessible active sites for electrochemical energy conversion and storage. Here, the synthesis, structures, and energy-related applications of mesoporous nanomaterials are the main focus. After a brief summary of synthetic methods of mesoporous nanostructures, the delicate design and construction of mesoporous nanomaterials are described in detail through precise tailoring of the particle sizes, pore sizes, and nanostructures. Afterward, their applications as electrode materials for lithium-ion batteries, supercapacitors, water-splitting electrolyzers, and fuel cells are discussed. Finally, the possible development directions and challenges of mesoporous nanomaterials for electrochemical energy conversion and storage are proposed.     

Lysozyme adsorption onto mesoporous materials: effect of pore geometry and stability of adsorbents

In this paper, adsorption of lysozyme onto two kinds of mesoporous adsorbents (KIT-5 and AISBA-15) has been investigated and the results on the effects of pore geometry and stability of the adsorbents are also discussed. The KIT-5 mesoporous silica materials possess cage-type pore geometry while the AISBA-15 adsorbent has mesopores of cylindrical type with rather large diameter (9.7 nm). Adsorption of lysozyme onto AISBA-15 aluminosilicate obeys a Langmuir isotherm, resulting in pore occupation of 25 to 30%. In contrast, the KIT-5 adsorbents showed very small adsorption capacities for the lysozyme adsorption, typically falling in 6 to 13% of pore occupation. The cage-type KIT-5 adsorbents have narrow channel (4 to 6 nm) where penetration of the lysozyme (3 x 3 x 4.5 nm) might be restricted. The KIT-5 adsorbent tends to collapse after long-time immersion in water, as indicated by XRD patterns, while the AISBA-15 adsorbent retains its regular structure even after immersion in basic water for 4 days. These facts confirm superiority of the AISBA-15 as an adsorbent as compared with the KIT-5 mesoporous silicates. This research strikingly demonstrates the selection of mesoporous materials is crucial to achieve efficient immobilization of biomaterials in aqueous environment.     

两步晶化法制备MCM-48/ZSM-5复合分子筛

利用两步晶化法制备了高水热稳定性的MCM48/ZSM-5介微孔复合分子筛.通过SEM、TEM、XRD、IR和N₂吸附脱附进行表征,结果显示,该材料的结构不同于简单的机械混合,而是具有微孔孔壁和三维立方介孔孔道的复合材料,其孔道尺寸为2.6nm左右.该复合分子筛在沸水中处理6h后,介孔结构仍保留完好.通过考察晶化时间对复合分子筛的影响,证明了介孔和微孔的组装是一个竞争的过程,复合分子筛中介孔与微孔结构的比例随晶化时间的变化而变化,且具有介孔孔道和微孔孔壁的复合分子筛150℃的最优晶化时间为8h.     

New families of mesoporous materials

Abstract

Mesoporous materials have been paid much attention in both scientific researches and practical applications. In this review, we focus on recent developments on preparation and functionalization of new families of mesoporous materials, especially non-siliceous mesoporous materials invented in our research group. Replica synthesis is known as the method to synthesize mesoporous materials composed of various elements using originally prepared mesoporous replica. This strategy has been applied for the syntheses of novel mesoporous materials such as carbon nanocage and mesoporous carbon nitride. Carbon nanocage has a cage-type structure with huge surface area and pore volume, which exhibits superior capabilities for biomolecular adsorption. Mesoporous carbon nitride was synthesized, for first time, by using mixed material source of carbon and nitrogen simultaneously. As a totally new strategy for synthesis of mesoporous materials, the elemental substitution method has been recently proposed by us. Direct substitution of component elements in original mesoporous materials, with maintaining structural regularity, provided novel mesoporous materials. According to this synthetic strategy, mesoporous boron nitride and mesoporous boron carbon nitride have been successfully prepared, for first time. In addition to these material inventions, hybridization of high functional materials, such as biomaterials, to mesoporous structure has been also developed. Especially, immobilization of proteins in mesopores was systematically researched, and preparation of peptidehybridized mesoporous silica was demonstrated. These new families of mesoporous materials introduced in this review would have high potentials in future practical applications in wide ranges from electronics and photonics to environmental and medical uses.     

New families of mesoporous materials

Mesoporous materials have been paid much attention in both scientific researches and practical applications. In this review, we focus on recent developments on preparation and functionalization of new families of mesoporous materials, especially non-siliceous mesoporous materials invented in our research group. Replica synthesis is known as the method to synthesize mesoporous materials composed of various elements using originally prepared mesoporous replica. This strategy has been applied for the syntheses of novel mesoporous materials such as carbon nanocage and mesoporous carbon nitride. Carbon nanocage has a cage-type structure with huge surface area and pore volume, which exhibits superior capabilities for biomolecular adsorption. Mesoporous carbon nitride was synthesized, for first time, by using mixed material source of carbon and nitrogen simultaneously. As a totally new strategy for synthesis of mesoporous materials, the elemental substitution method has been recently proposed by us. Direct substitution of component elements in original mesoporous materials, with maintaining structural regularity, provided novel mesoporous materials. According to this synthetic strategy, mesoporous boron nitride and mesoporous boron carbon nitride have been successfully prepared, for first time. In addition to these material inventions, hybridization of high functional materials, such as biomaterials, to mesoporous structure has been also developed. Especially, immobilization of proteins in mesopores was systematically researched, and preparation of peptide-hybridized mesoporous silica was demonstrated. These new families of mesoporous materials introduced in this review would have high potentials in future practical applications in wide ranges from electronics and photonics to environmental and medical uses.     

埃洛石原料无模板法制备高比表面积介孔氧化硅及其在亚甲基蓝吸附中的应用

采用无模板法, 以天然的矿物原料制备介孔材料是一种经济有效的制备方法。本研究利用“煅烧-沸石化-酸处理”工艺制备高比表面积的介孔氧化硅颗粒。研究发现,通过长时间的碱处理将煅烧埃洛石转化为沸石,随后通过酸处理,可制备出比表面积高达767 m²/g的介孔氧化硅材料。该工艺机理为: 850℃煅烧使埃洛石转变为无定型态的Si-O-Al网络结构,煅烧埃洛石在长时间的水热碱处理过程中转化为结晶态的LTA沸石硅铝酸钠,在随后的强酸性环境下,沸石的Al-O和Na-O成分被完全溶解,而残余的Si-O纳米碎片在酸环境中相互聚合,生成无定形态的介孔氧化硅颗粒。本实验制备的介孔氧化硅比表面积高达767 m²/g,最可几孔径为5 nm,其亚甲基蓝平衡吸附量可达741 mg/g,表明其在污染物吸附中具有良好的应用潜力。     

Assemblies of biomaterials in mesoporous media

Assemblies of biomaterials onto mechanically stable inorganic structure are advantageous for the practical applications because of the potential to improve the stability and performance of biomaterials in the biocatalytic processes. Among many kinds of inorganic materials, mesoporous materials such as mesoporous silica and mesoporous carbon have attracted special attention owing to their well-defined structures and perfectly controlled pore geometries, which would lead to unique functions such as size selective adsorption of biomaterials. In the first part of this review, adsorption behaviors of proteins, enzymes, vitamins, and amino acids in aqueous solutions onto mesoporous media are systematically explained. Pore geometries (pore diameter and volume) of mesoporous materials are the crucial factors for the size selective adsorption of biomaterials, especially proteins, which often have a size comparable to pore dimension. The studies on the adsorption of biomaterials on the mesoporous carbon reveal that hydrophobic interaction between guest molecules and surface of the mesoporous materials is an important parameter which controls the amount of biomaterials adsorption. Enhanced adsorption of biomaterials was commonly observed at their isoelectric point, where electrostatic repulsion is minimized between the biomaterials. In addition, several functions such as biomolecular separation, reactor function, controlled drug release, and photochemical properties are discussed in the latter sections. Studies on assemblies of biomaterials in mesoporous media are still in initial stage, but the development of appropriately designed mesoporous materials would powerfully promote researches in these fascinating unexplored fields.     

Quick high-temperature hydrothermal synthesis of mesoporous materials with 3D cubic structure for the adsorption of lysozyme

Abstract

Three-dimensional cage-like mesoporous FDU-12 materials with large tuneable pore sizes ranging from 9.9 to 15.6 nm were prepared by varying the synthesis temperature from 100 to 200 °C for the aging time of just 2 h using a tri-block copolymer F-127(EO₁₀₆PO₇₀EO₁₀₆) as the surfactant and 1,3,5-trimethyl benzene as the swelling agent in an acidic condition. The mesoporous structure and textural features of FDU-12-HX (where H denotes the hydrothermal method and X denotes the synthesis temperature) samples were elucidated and probed using x-ray diffraction, N₂ adsorption, ²⁹Si magic angle spinning nuclear magnetic resonance, scanning electron microscopy and transmission electron microscopy. It has been demonstrated that the aging time can be significantly reduced from 72 to 2 h without affecting the structural order of the FDU-12 materials with a simple adjustment of the synthesis temperature from 100 to 200 °C. Among the materials prepared, the samples prepared at 200 °C had the highest pore volume and the largest pore diameter. Lysozyme adsorption experiments were conducted over FDU-12 samples prepared at different temperatures in order to understand their biomolecule adsorption capacity, where the FDU-12-HX samples displayed high adsorption performance of 29 μmol g^?1 in spite of shortening the actual synthesis time from 72 to 2 h. Further, the influence of surface area, pore volume and pore diameter on the adsorption capacity of FDU-12-HX samples has been investigated and results are discussed in correlation with the textural parameters of the FDU-12-HX and other mesoporous adsorbents including SBA-15, MCM-41, KIT-5, KIT-6 and CMK-3.