Mn‐Loaded Mesoporous Silica Nanocomposite: A Highly Efficient Humidity Sensor

We report a relative humidity sensor based on manganese‐nanoparticle‐loaded mesoporous silica SBA‐15 using a facile hydrothermal route. The as‐developed nanocomposite material (Mn/SBA‐15) possesses a high surface area and a high pore volume. The obtained samples were characterized by using low‐angle X‐ray Diffraction (XRD), Fourier‐transform infrared spectroscopy (FTIR), N₂ adsorption–desorption, high‐resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), and energy‐dispersive X‐ray (EDX) spectroscopy techniques. The Mn/SBA‐15 exhibited, improved humidity response and recovery time as compared to pure SBA‐15 in the 11%–92% RH range. Optimal results were obtained for the 5 wt% Mn‐loaded SBA‐15 sample, which displayed excellent linearity, low hysteresis, and high humidity response. A change in ~5 orders of magnitude in resistance was observed over 11%–92% RH range. The investigation of humidity sensing properties of Mn/SBA‐15 nanocomposite shows that this material has good prospects as humidity sensor.     

以十二烷基三甲基溴化铵为模板制备高度有序的介孔二氧化硅材料

以长碳链阳离子表面活性剂如十六烷基三甲基溴化铵为模板,可制得高度有序的介孔二氧化硅材料,而碳链较短的表面活性剂如十二烷基三甲基溴化铵,由于其表面活性较差,以其为模板难以制得有序介孔二氧化硅材料.以十二烷基三甲基溴化铵为模板剂,考察了不同硅源、碱源以及pH值对介孔材料结构的影响,采用XRD、FTIR、SEM、HRTEM和N2物理吸附等手段分别对产物的晶体结构、织构性质、形貌和孔道结构进行表征.结果 表明,以正硅酸乙酯为硅源,在有机碱四甲基氢氧化铵存在下,以十二烷基三甲基溴化铵为模板,制得了具有规整六方结构的高度有序介孔二氧化硅材料,其孔径和晶胞常数分别为2.25 nm和3.72 nm.     

三维孔道硅基介孔材料对Cd2+的吸附特性

采用三嵌段聚合物F127(EO106PO70EO106)为结构导向剂,正硅酸乙酯为硅源,使用无机盐(K2SO4)以增加有机物种的自组装能力,在稀酸(0.5mol/L)条件下合成了三维孔道硅基介孔材料。研究表明:介孔材料具有良好的晶体结构,属三维立方孔空穴Im3m结构;介孔排列有序,孔径分布均匀,平均孔径为3.3nm,孔容为0.51cm3/g,比表面积为611.2 m2/g。探讨了介孔材料用量、吸附液pH值、温度和初始浓度等因素对Cd2+吸附性能的影响,结果表明,介孔材料吸附Cd2+的适宜工艺条件为介孔材料用量4 g/L、吸附液pH=7、吸附温度40℃。用Langmuir和Freundlich等温吸附方程拟合了三维孔道硅基介孔材料对Cd2+的吸附过程,表明吸附过程为单层吸附,40℃时最大理论吸附量为9.253mg/g。     

有机胺改性多孔材料制备固体胺二氧化碳吸附剂的研究进展

人类社会排放的温室气体逐年增多,全球变暖问题日益严重,二氧化碳减排已迫在眉睫。有机胺改性多孔材料制备的固体胺吸附剂,二氧化碳吸附性能十分优越,具有良好的工业应用前景。本文综述了介孔分子筛、硅胶、多孔炭材料等多种多孔材料载体负载有机胺制备固体胺吸附剂的方法,分析了其二氧化碳吸附性能,讨论了多孔材料的孔结构对吸附剂吸附性能的影响。     

有序二氧化硅介孔固体材料制备的研究进展

有序二氧化硅(SiO2)介孔固体是近年来研究的一类用以组装纳米结构材料的载体. 本文概述了近年来这类介孔固体材料制备的研究进展情况,介绍了不同反应体系和反应条件对介孔的有序性、介孔尺寸、介孔壁厚以及材料的孔隙率和热稳定性的影响.     

改性钙基材料吸附CO2性能研究

温室气体CO2的大量排放是全球气候变暖的主要影响因素,对于CO2的捕集再利用研究已引起了学界和工业界的广泛关注.石灰石循环煅烧/碳酸化法捕集工业CO2气体已经被大量报道,但石灰石在循环捕集过程当中其表面容易被烧结而降低了其捕集性能,基于此,我们提出了利用耐高温氧化物(如MgO、Fe2O3、SiO2)微粒对石灰石颗粒表面进行修饰改性以便提高石灰石颗粒的抗烧结能力及其CO2捕集特性并利用TGA和SEM对改性实验进行了捕集性能测试和颗粒形貌表征.试验结果表明,金属氧化物微粒对石灰石改性有效果,其中添加1 wt％ MgO微粒时可以使石灰石捕集CO2的性能提高7％～8％,且吸收剂颗粒孔隙结构得以改善.     

氨基功能化介孔硅材料对SO_2吸附性能研究

以十六烷基三甲基溴化铵作为结构导向剂,正硅酸乙酯作为硅源,3-氨基丙基三乙氧基硅烷作为功能基团,采用共缩聚的方法制备了一系列氨基功能化介孔硅材料(AFM),并研究其对二氧化硫气体的吸附性能。采用N2吸附、X射线衍射、红外光谱、透射电镜等手段对材料进行表征。实验结果表明,氨基功能化介孔硅材料具有较大的比表面和孔体积,对酸性二氧化硫气体有较强的吸附能力。     

Mesoporous Silica Sorbents Impregnated with Blends of Tetraethylenepentamine and Alkanolamine for CO2 Separation

Mesocellular silica foam (MSU-F) supports were functionalized via wet impregnation with various amine and alcohol compounds for use as high-capacity adsorbents for CO₂ separation. The effect of the amino, hydroxyl, and ether functional groups in the impregnating mixture on the CO₂ adsorption capacity was investigated. Chemical adsorption was controlled by the composition of the compounds, and the blending effect on the adsorption performance was dependent on the temperature. MSU-F (30 wt.%) impregnated with a mixture of tetraethylenepentamine (40 wt.%) and aminoethylethanolamine (30 wt.%) showed a high adsorption capacity of 5.4 mmol/g at 333 K for 15 kPa CO₂.     

介孔分子筛SBA-15的研究进展

自从介孔分子筛SBA - 15首次合成出来 ,成为众多研究领域的一个研究热点。文章综述了介孔分子筛SBA -15的合成及机理 ,影响孔径尺寸的因素及研究应用进展 ,介孔分子筛SBA - 15在催化、吸附和分离及纳米材料等领域具有广泛的应用前景。     

介孔硅材料在止血应用方面的研究进展

介绍了介孔硅材料的类型以及合成方法,综述了以介孔硅材料为基材的止血材料的研究现状,主要包括介孔硅材料、介孔硅与有机材料的复合、介孔硅与金属离子材料的复合,介孔硅材料均显示了良好的止血和抗菌性能,最后展望了介孔硅与其他材料复合在止血应用方面的前景。     

硅基介孔材料的制备与应用研究进展

硅基介孔材料是通过有机与无机物组份间的超分子组装或协同效应而杂化形成。它具有较大的孔容、高的比表面积、有序且可调的孔道结构,其孔道表面可进行物理吸附或新的化学修饰。这为介孔材料的功能化与应用研究提供了有力的保证。对硅基介孔材料的基本制备方法作了介绍,重点对国内外硅基介孔材料的应用研究进展进行了综述。     

Kinetics of CO2 Adsorption/Desorption of Polyethyleneimine‐Mesoporous Silica

The kinetics of adsorption of CO₂ on solid sorbents based on polyethyleneimine/mesoporous silica (PEI/MPS) was studied by following the mass gain during CO₂ flow. Linear (PEI‐423) and branched (PEI‐10k) polymers were studied. The solid sorbents were synthesized by impregnating the PEI into MPS foam. The kinetics of adsorption was fitted with a double‐exponential model. In contrast, the desorption process obeyed first‐order kinetics. The activation energy of desorption of PEI‐423 was lower than that of PEI‐10k, presumably because the branched polymer required more energy to expose its nitrogen to CO₂. To increase the CO₂ sorption capacity, the MPS was treated with nonionic surfactant materials prior to impregnation with PEI. This also lowered the maximum sorption temperature and desorption activation energies.     

Pt-supported Spherical Mesoporous Silica as a Nanosized Catalyst for Efficient Liquid-Phase Hydrogenation

Mesoporous silica nanospheres with an average diameter of approximately 240 and 600 nm have been used as catalyst supports of active Pt nanoparticles, which were found to be highly efficient for liquid-phase hydrogenation under atmospheric H₂ compared to the micron-sized conventional mesoporous silica because of the suppression of mass-transport limitation toward active sites.     

固废源CaO基CO2捕集材料的制备与捕集性能研究进展

CO₂捕集技术是当前应对全球气候变化、缓解温室效应的重要途径。利用含钙固体废弃物制备高效CaO基CO₂捕集材料有利于实现固废资源高值化利用、以废治废和清洁生产,具有重要的环境效益、经济效益和社会效益。基于固废源高效廉价CaO基CO₂捕集材料的良好应用前景,本文介绍了工业废渣、生物质和其他含钙固体废弃物的产生与资源化利用现状,综述了CaO基吸附剂的捕集原理、碳酸化动力学过程和CO₂捕集性能,对比了以不同含钙固体废弃物为前驱体制备CaO基吸附剂的吸附-脱附循环性能和不同改性方法对其吸附稳定性的影响,从经济角度分析了固废源CaO基吸附剂在钢铁厂、燃煤电厂和生物制氢中的应用潜力,展望了固废源CaO基CO₂捕集材料的应用前景和发展方向。该文旨在为固废源CaO基吸附剂前驱体的选择、吸附性能的提高和固废吸附材料的工业应用提供帮助。     

Improving Physical Adsorption of CO2 by Ionic Liquids‐Loaded Mesoporous Silica

CO₂ sorption capacities of the neat and silica‐supported 1‐butyl‐3‐methylimidazolium‐based ionic liquids (ILs) were measured under atmospheric pressure. The silica‐supported ILs were synthesized by the impregnation‐vaporization method and charactrized by N₂ adsorption/desorption and thermogravimeteric analysis (TGA). Evaluation of the effects of influential factors on sorption capacity demonstrated that by increase of the temperature, flow rate, and the weight percentage of ILs in sorbents, the sorption capacity decreases. Among the sorbents, [Bmim][TfO] and SiO₂‐[Bmim][BF₄](50) had the highest capacity. By increasing the IL portion in SiO₂‐[Bmim][BF₄], the selectivity for CO₂ to CH₄ could be improved. The CO₂‐rich sorbents could be easily recycled.     

Synthesis and Characterization of Highly Dispersed Molybdenum Carbides in Mesoporous Silica

Highly dispersed molybdenum carbides in MCM-41 mesoporous silica are synthesized by temperature-programmed carburization and are characterized. Two methods of preparation are examined: (i) insertion of molybdenum during the synthesis of the MCM-41 silica and (ii) postsynthesis incorporation into a MCM-41 silica matrix by the incipient wetness method. Propene transformation (hydrogenation and metathesis) was used as a probe reaction; the observed catalytic behavior can be explained as a result of the preparation method, i.e., of the relative strength of interaction between the molybdenum oxide precursor and the support.     

Synthesis of Mesoporous Silica Materials via Nonsurfactant Urea-Templated Sol-Gel Reactions

Mesoporous silica materials with pore diameters of 2 to 6 nm have been prepared using urea as a nonsurfactant template or pore-forming agent in HCl-catalyzed sol-gel reactions of tetraethyl orthosilicate, followed by removing the urea molecules by extraction with methanol or water. Characterization results from nitrogen sorption isotherm, powder X-ray diffraction, and transmission electron microscopy indicate that the materials have large specific surface areas (e.g., 600 m²/g) and pore volumes (e.g., 0.8 cm³/g) as well as narrow pore size distributions. The mesoporosity is arisen from interconnecting wormlike channels and pores of regular diameters. As the urea concentration is increased, the nitrogen sorption isotherms of the silica matrices transform from the reversible type I to the type IV form with type H2 hysteresis, along with increases in the diameter and volume of the pores.     

聚苯胺基多孔炭制备及 CO 捕集性能研究

以聚苯胺为原料,采用NaOH活化法,在原料与活化剂质量比为1砄4的情况下,研究了不同的活化时间（0.5 h、1 h、2 h）对多孔炭孔隙结构和CO2吸附性能的影响。通过N2吸附脱附、扫描电子显微镜（SEM）、透射电子显微镜（TEM）,对样品的孔隙结构和形貌进行了表征。采用变压吸附法在常温常压下测试了样品对CO2的吸附性能。结果表明：当活化时间为1 h时,比表面积达到最大值2024 m2／g,微孔孔容达到最大值0.926 cm3／g。然而,当活化时间为0.5 h时, CO2吸附量达到了最大值159 mg／g,表明了CO2吸附量与窄微孔孔径分布有直接关系。     

Two Facile Aniline-Based Hypercrosslinked Polymer Adsorbents for Highly Efficient Iodine Capture and Removal

Effective capture and safe disposal of radioactive iodine (¹²⁹I or ¹³¹I) during nuclear power generation processes have always been a worldwide environmental concern. Low-cost and high-efficiency iodine removal materials are urgently needed. In this study, we synthesized two aniline-based hypercrosslinked polymers (AHCPs), AHCP-1 and AHCP-2, for iodine capture in both aqueous and gaseous phases. They are obtained by aniline polymerization through Friedel–Crafts alkylation and Scholl coupling reaction, respectively, with high chemical and thermal stability. Notably, AHCP-1 exhibits record-high static iodine adsorption (250 wt%) in aqueous solution. In the iodine vapor adsorption, AHCP-2 presents an excellent total iodine capture (596 wt%), surpassing the most reported amorphous polymer adsorbents. The rich primary amine groups of AHCPs promote the rapid physical capture of iodine from iodine water and iodine vapor. Intrinsic features such as low-cost preparation, good recyclability, as well as excellent performance in iodine capture indicate that the AHCPs can be used as potential candidates for the removal of iodine from radioactive wastewater and gas mixtures.