Design and Development of Amine Functionalized Mesoporous Cubic Silica Particles: A Recyclable Catalyst for Knoevenagel Condensation

Catalysis Letters - The amine functionalized cubic mesoporous silica nanoparticles (cSiO2-NH2) were successfully synthesized through biphasic stratification approach. The synthesized material was...     

High Temperature Nanocomposite Through Engineered Synthesis of Hafnia Nano-Dispersoids in Hexagonal Mesoporous Silica

In this communication, we show a solution-based synthetic route that yields a dual-phase SiO₂-based ceramic–ceramic composite capable of retaining nano-structural features up to very high temperatures. The nanocomposite was produced by self-assembly of mesoporous silica using a non-ionic surfactant, and subsequent infiltration of the mesoporosity with a solution containing a high-temperature metal-oxide-based composition (HfO₂). The nanocomposite was consolidated and processed up to 1500°C.     

Synthesis and Characterization of Mesoporous Silica Functionalized with Calix[]arene Derivatives

This work reports a new method to covalently attach calix[4]arene derivatives onto MCM-41, using a diisocyanate as a linker. The modified mesoporous silicates were characterized by fourier transform infrared spectroscopy (FTIR), thermal analysis (TGA) and elemental analysis. The FTIR spectra and TGA analysis verified that the calix[4]arene derivates are covalently attached to the mesoporous silica. The preservation of the MCM-41 channel system was checked by X-ray diffraction and nitrogen adsorption analysis.     

磁性介孔二氧化硅微球的研究及应用进展

磁性介孔二氧化硅微球作为一种新型纳米复合材料,广泛应用于众多领域.综述了近年来磁性介孔二氧化硅微球的制备方法,并对其在靶向药物、生物富集与分离、磁热疗、固定化酶等生化领域的应用作了介绍.     

铁氧体磁性复合材料去除阴离子污染物的研究进展

铁氧体磁性纳米材料因其高比表面积、吸附速度快、易被外磁场分离等显著优势,在水处理方面已经成为一个研究热点,然而它的应用受到低的吸附性能的限制,目前许多研究将铁氧体与有机物或无机物复合来解决这一问题.本文介绍了铁氧体复合材料的制备流程,并对铁氧体磁性复合材料在吸附阴离子污染物应用方面的研究进展进行了综述,最后展望了该类材...     

介孔二氧化硅微球的扩孔及组装磁性纳米铁粒子

以十六胺为模板剂、正硅酸乙酯(TEOS)为硅源合成孔径约3 nm的多孔球形结构介孔二氧化硅(MS)材料. 为满足组装磁性纳米粒子所需的孔径要求,提出了一种可较大程度扩大孔径的方法?复盐浸渍法,用多组分盐溶液(NaC1:LiCl:KNO3=4:1:1, w)浸渍MS微球,然后在300℃加热2 h,扩大MS孔径,扩孔后的MS微球孔径在10 nm左右. 采用电化学方法在MS介孔内合成Fe纳米粒子,并在H2气氛下加热还原得到Fe/SiO2磁性复合微球,制备出的磁性复合微球孔道内均匀地分布着Fe粒子.     

Asymmetric Catalysis in Confined Space Provided by l-Proline Functionalized Mesoporous Silica with Plugs in the Pore

Mesoporous silica having l-proline functionality and plugged pore structure was synthesized by direct microwave synthesis under acidic condition using Pluronic P123 as template and sodium metasilicate nonahydrate as silica source. The direct synthesis resulted in the prismatic or disk types with short channels and plugs in the pore structure. Due to the presence of plugs, dual mesoporosities with 7 and 3 nm pore diameter were generated leading to an existence of cavitation. Tri-functionality of this materials i.e. chiral organofunctional group, plugs, and short channel, would be useful for the asymmetric diethyl malonate addition reaction and asymmetric epoxidation reaction of α,β-unsaturated aldehydes. We proved that the formation of plugs in the mesoporous silica governs the formation of dual mesoporosities providing an enhancement of enantiomeric excess in the asymmetric catalysis. This finding might open an important application of the amino-acid organo multifunctionalized mesoporous silica for asymmetric reactions.     

Removal of Pollutants from Solid Matrices Using Supercritical Fluids

Abstract

Several supercritical fluid extraction (SCFE) processes have been proposed for removing toxic and intractable organic compounds from a range of contaminated solids. These include soil remediation and the regeneration of adsorbents used to treat wastewater streams such as granular activated carbon (GAC). As a separation technique for environmental control, SCFE has several distinct advantages over conventional liquid extraction methods and incineration. Most notably, the contaminant is removed from the solvent in a concentrated form via a change in pressure or temperature and can be completely separated upon expansion to atmospheric pressure.

The viability of SCFE hinges on process conditions such as solvent-feed ratio and solvent recycle ratio. The necessity of recycling solvent complicates the contaminant separation step since a complete reduction to atmospheric pressure would create large recompression costs. Because of this, the pressure and temperature dependence of contaminant solubility must be understood so that operating conditions for the separation step can be defined. Fortunately, this is the most developed aspect of SCF technology. However. the mass transfer limitations to removing contaminants from solids change with solvent flow rate.

This paper discusses the use of SCFE for environmental control and presents results for the removal of DDT and 2-chlorophenol from GAC. 2-chlorophenol is almost completely removed with pure CO₂ at 40°C and 101 bar while only 55% of the DDT is removed at 40°C and 200 bar. These differences in regeneration efficiency cannot be understood solely in terms of solubility but point to a need for detailed studies of adsorption equilibrium and mass transfer resistances in supercritical fluid systems.     

Application of Magnetic ordered mesoporous carbon Nanocomposite for the Removal of Ponceau 4R Using Factorial Experimental Design

Silicon - Nanocomposites of ordered mesoporous carbon with silica coated magnetite nanoparticles (Fe3O4@SiO2-CMK-8, MNCs) were synthesized by carbonizing sucrose inside the pores of the Kit-6...     

Synthesis and Structural Characterization of G-SBA-IDA,G-SBA-EDTA and G-SBA-DTPA Modified Mesoporous SBA-15 Silica and Their Application for Removal of Toxic Metal Ions Pollutants

Silicon - Modified mesoporous SBA-15 silica materials (G-SBA-IDA, G-SBA-EDTA and G-SBA-DTPA) (where IDA, EDTA and DTPA represent iminodiacetic acid, ethylenediaminetetraacetic acid and...     

双功能磁性木质素纳米材料的制备及其去除水中污染物的研究

为了提高木质素的高价值转化,同时实现废水中染料污染的处理。通过一步共沉淀法制备了多功能的磁性木质素纳米复合材料(MASL),并用于除去水中的有机染料。利用傅里叶红外(FTIR)、热重分析(TG-DTG)以及振动样品磁强计(VSM)等一系列技术手段分析材料的物理化学性质。吸附实验表明磁性木质素复合材料对亚甲基蓝(MB)和甲基橙(MO)的最大吸附量为355.85 mg/g和222.72 mg/g,且能够在120min内快速达到吸附平衡。其吸附行为符合Langmiur等温吸附模型以及拟二级动力学模型。此外,材料的磁滞回归线表明其具有优异的超顺磁性,能够通过磁分离快速从水中回收,表明其在实际应用中从废水中去除染料的巨大潜力。     

One-Step Fabrication of Magnetic Carbon Nanocomposite as Adsorbent for Removal of Methylene Blue

Magnetic Fe₃O₄@C nanocomposites with well-defined core@shell structure were synthesized via a facile one-step solvothermal process using ferrocene as both iron and carbon resource in the presence of hydrogen peroxide (H₂O₂). The as-prepared Fe₃O₄@C nanocomposites were employed as adsorbent materials for removal of methylene blue (MB) from aqueous solution. Several experimental parameters, including contact time, acidity of the solution, and initial MB concentration were investigated. The result showed that the equilibrium uptake of MB was related to the MB initial concentration as well as acidity of the solution. The adsorption kinetics of MB was dominated by the pseudo-second order reaction model. Significantly, the synthesized Fe₃O₄@C nanocomposites could be easily isolated from the adsorption system after adsorbing MB and showed prominent reusability. All results indicated that the prepared Fe₃O₄@C composites had the potential to be used as adsorbents for the removal of dye pollutant from wastewater.     

胺/氨类混合液中胺或氨含量的检测方法

介绍胺/氨类混合液中胺或氨含量的检测方法。首先用卡氏水分测定仪测试混合液中的水分含量,再结合酸碱滴定法测试混合液中每种化合物的含量。该方法测量精确,可以将回收的胺或氨类化合物作为原料在实际生产过程中加以循环利用。     

Influence of Mesoporous Silica and Butyral Content on the Mechanical,Water Absorption,and Permeability Properties of in situ Synthesized Silica/PVB Nanocomposite Films

Poly(vinyl butyral)–silica nanocomposites were synthesized in situ with three different degrees of butyral and with varying silica content for each vinyl butyral polymer ratio. The glass transition temperatures of the polymer nanocomposites were found to be ～40–46 and ～52°C for the neat polymer, respectively. The 4 wt% silica loaded film showed higher strength and lower strain to failure compared with the neat polymer. The matrix with 0.5 and 0.75 butyral:alcohol for 2.5–4 wt% silica exhibited good water vapor transmission and the efficiencies of these films were 50% higher than their encapsulated pristine polymer films.     

Preparation of Folic Conjugated Magnetic Silica Mesoporous Nanoparticles and Their Encapsulated 10-HCPT Anticancer Behavior

Journal of Inorganic and Organometallic Polymers and Materials - A novel folate-decorated and magnetic mediated drug delivery system was fabricated by combining folate and magnetic nanoparticles to...     

Removal of Toxic/Heavy Metal Ions Using Ion-Imprinted Aminofunctionalized Silica Gel

Abstract

The investigation reports the preparation and evaluation of Cr(III) and Fe(III)-imprinted amino-functionalized silica gel adsorbents (APTS-Cr(III)-Si and APTS-Fe(III)-Si) for selective solid-phase extraction of Cr(III) and Fe(III), respectively, from aqueous solutions. The adsorbent materials were prepared by a surface imprinting technique using 3-aminopropyltrimethoxysilane as the surface modifying ligand. The effects of solution pH, sorption time, temperature, and initial metal ion concentration upon adsorption characteristics were investigated. The adsorption isotherms for Langmuir, Freundlich, and Dubinin-Radushkevich (D-R) were evaluated and the thermodynamics of the adsorption processes were correlated. By optimizing the parameters, the synthesized materials could be used successfully for selective removal of trivalent cations from a mixture of cations in dilute aqueous solution.     

Applications of Amine-functionalized Mesoporous Silica in Fine Chemical Synthesis

SBA-15 silica containing homogeneously distributed amine-functional groups and of fiber or platelet morphology was prepared through a modified co-condensation method using P123 copolymer as template under acidic condition. Synthetic factors which led to well-ordered mesoporous materials with high loadings of various amine groups were discussed. The resultant mesoporous materials were efficient base catalysts in Knoevenagel and Claisen–Schmidt addition reactions. The activities over SBA-15 materials with different amino-functional groups are compared. Moreover, the advantage of ordered large mesopores of SBA-15 in catalyzing liquid phase reactions was demonstrated, and the reaction rate could be further increased when SBA-15 was with platelet morphology and short mesochannels.     

氧化硅介孔材料的研究进展

介绍了介孔材料的定义及分类，阐明了氧化硅介孔材料的合成方法和形成机理，并总结了氧化硅介孔材料的应用领域及应用前景研究情况。     

Low-Cost Magnetic Fe3O4/Chitosan Nanocomposites for Adsorptive Removal of Carcinogenic Diazo Dye

Theoretical Foundations of Chemical Engineering - The eco-friendly adsorptive removal of Congo red (CR) from aqueous medium using Fe3O4/chitosan nanocomposites was investigated. The nanocomposites...