新型SiO2/SiO2核壳型固定相的制备与评价

采用层层自组装的方法,以微米多孔硅胶小球为核,将硅胶纳米粒子多层包覆,制备了核壳型SiO2/SiO2硅胶小球.透射电子显微镜表明这种硅胶小球具有明显的核壳结构,氮气吸附实验证明该硅胶小球是典型的介孔材料,具有良好的介孔结构和窄的孔径分布.将其作为基质制备碳十八键合核壳型SiO2/SiO2色谱固定相,该固定相的碳含量与未...     

介孔C/SiO2粉体的制备及对阳离子型染料的吸附

采用吸附法处理染料废水需要合适的吸附剂。利用溶剂蒸发自组装法,以甲阶酚醛树脂为碳源、介孔SiO2粉体为载体制备介孔C/SiO2粉体,表征所制C/SiO2粉体的结构,研究C/SiO2粉体对阳离子型染料亚甲基蓝和阳离子红X-GRL的吸附性能,并与相同条件下制备的非负载的多孔C粉体以及介孔SiO2载体进行比较。结果表明,介孔C/SiO2粉体的孔窗口为11~18 nm,比表面积为303 m2.g-1,比孔容为1.11 cm3.g-1;C/SiO2粉体对这两种染料吸附量均高于C粉体和SiO2载体;在pH≤10的范围内,吸附量随pH值增大而显著提高。     

Facile synthesis of bioglass nanospheres for the adsorption of cationic and anionic dyes from aqueous solution

A novel adsorbent, bioglass nanospheres (BGN), has been prepared by a facile process. The BGN were spheres with an amorphous structure and a relatively high specific surface area, as indicated by SEM, transmission electron microscopy, BET, FTIR, and XRD. This paper was aimed at evaluating the adsorption behavior of this new material for the adsorptive removal of cationic (methylene blue, neutral red) and anionic (congo red) dyes from aqueous solution. The effects of the initial dye concentration, contact time, solution pH, and temperature were investigated. The adsorption kinetics showed that the adsorption behavior followed the pseudo-second-order kinetic model. The adsorption isotherm fit well to the Langmuir model. Thermodynamic analyses showed that the adsorption was physisorption, and it was also a spontaneous and endothermic process. The BGN exhibited a good reusability after five consecutive cycles for cationic dyes. In addition, the possible adsorption mechanism was also proposed based on the above experimental results.     

氨水诱导硅核自组装制备介孔SiO_2

在无模板剂的条件下,通过控制氨水用量,利用正硅酸乙酯水解制备了粒径约20 nm的SiO2初级粒子;随后用过量氨水诱导SiO2初级粒子交联生长,得到孔径在10~50 nm、孔容达2.05 cm3.g-1的介孔SiO2;考察了介孔SiO2的吸附性能.结果表明,所制备的介孔SiO2具有优良的吸附性能.     

Interaction between congo red and copper in a binary adsorption system: Spectroscopic and kinetic studies

This study focused on the competitive adsorption of congo red (CR) and copper by chitosan hydrogel beads in a binary adsorption system. Spectroscopic analysis, including Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) were integrated with kinetic studies to elucidate the interaction. It was determined that chitosan hydrogel beads show better adsorption performance towards congo red and copper in single adsorption systems. The addition of copper caused a 25% reduction in congo red adsorption capacity, while copper adsorption was enhanced slightly by the presence of congo red. The adsorption results for binary adsorption systems seem due to competition for the present amine and hydroxyl groups that may occur between congo red and copper. A congo red–copper complex was formed in binary adsorption systems. Copper attached to chitosan hydrogel beads individually or was bound by the congo red–copper complex, which resulted in an increase in adsorption capacity. Chitosan exhibited higher adsorption selectivity to the free Cu²⁺ ion than the congo red–copper complex in the binary adsorption system. Adsorption of the congo red–copper complex indicated an inhibition in the attachment of the free Cu²⁺ ion in the form of Cu(II).     

The effect of interfacial microstructure on the lipid oxidation stability of oil-in-water emulsions

Novel rattle-type magnetic mesoporous carbon spheres are successfully prepared using composite spheres with Fe(3)O(4) as core and mesoporous SiO(2) as shell plus solid SiO(2) as a middle layer as templates. These rattle-type spheres possess the magnetization strength of as high as 37.5 emu/g, high and tunable specific surface areas (382-512.6 m(2)/g) due to mesoporous carbon shells. This magnetic rattle-type structure and the readily accessible mesoporous shell are very favoring for the fast adsorption and release of guest objects triggered by external stimulus, for example, the spheres showed very good adsorptive property to dye.     

A mesoporous template route to the low-temperature preparation of efficient green light emitting Zn2SiO4:Mn phosphors

Green light emitting Zn2SiO4:Mn phosphors have been prepared via a low-temperature solid-state reaction using mesoporous silica SBA-15 template. This mesoporous silica template method features low-temperature formation of phosphors and easy doping. The structure and morphology of the phosphors were characterized by XRD, SEM, TEM, and N2 adsorption/desorption techniques, which confirmed the single crystallinity, ordered mesostructure, closed pore channels, and elongated ropelike morphology. The luminescent properties were examined by photoluminescence spectroscopy at room temperature, and the results of fluorescence decay time measurements show non-single-exponential decay behavior and a decrease of the decay time with an increase of the Mn concentration.     

乙二胺硅胶复合材料对Zn2+的吸附特性

以γ-氯丙基三氯硅烷为偶联剂,将乙二胺偶合接枝在硅胶表面,合成对锌离子具有吸附作用的乙二胺硅胶复合材料（EDA/SiO2）,考察了Zn2+溶液pH值、初始浓度、吸附温度和吸附时间等因素对复合材料吸附性能的影响。 结果表明,在研究的溶液浓度及温度范围内,Zn2+溶液pH值对EDA/SiO2的吸附量影响显著,吸附的最佳pH值范围在3.0~5.5;Zn2+的吸附平衡数据符合Langmuir吸附模型,热力学数据显示,EDA/SiO2对Zn2+的吸附行为为一吸热且自发进行的过程,升高温度有利于吸附,并对此吸附行为作了解释;吸附动力学数据可用拟二级吸附动力学方程描述,得到的吸附速率常数与溶液初始浓度有关。     

SiO_2担载的CuO_x纳米粒子量子尺寸效应的红外光谱研究

以硝酸铜作为前驱体,利用尿素作为沉淀剂,采用均相沉积沉淀方法合成了具有纳米尺寸CuOx的CuOx/SiO2材料,并通过改变样品的焙烧温度,得到了一系列具有不同纳米尺寸CuOx的CuOx/SiO2材料.采用TEM和原位红外光谱技术对CuOx纳米粒子的形貌、尺寸以及CO吸附性能进行了表征.结果表明,随着样品焙烧温度的升高,球形CuOx纳米粒子逐渐聚集,其尺寸从3 nm增加到11 nm,CO在CuOx上吸附的红外峰峰强逐渐减弱,并且红外频率从2135 cm-1红移到了2120 cm-1.研究结果表明,随着CuOx纳米粒子尺寸的增加,吸附中心Cuδ+离子的正电荷密度逐渐减小,导致Cuδ+离子与CO分子之间的电场相互作用变弱,使得CO分子在Cuδ+离子上吸附的红外频率发生了红移.说明在这个纳米尺寸范围内,CuOx纳米粒子具有明显的量子尺寸效应,不同尺寸的CuOx纳米粒子,其电子结构性质明显不同.     

氨基功能化SBA-16对CO_2的动态吸附特性

采用浸渍法将四乙烯五胺(TEPA)负载到介孔分子筛SBA-16的孔道内,形成功能化的介孔材料用于CO2的吸附.利用X射线衍射(XRD)、透射电镜(TEM)、氮气物理吸附-脱附和热重分析(TGA)等方法对样品进行了表征.通过动态吸附对不同TEPA浸渍量的SBA-16的CO2吸附性能和再生性能进行研究.结果表明:修饰后的SBA-16仍然保持有序的孔道结构,但样品的孔道有序度降低,比表面积、孔容、平均孔径都减小.样品对CO2的饱和吸附容量和穿透吸附容量随着TEPA浸渍量的增加而增加.60℃时,30%TEPA浸渍量的样品的穿透吸附容量和饱和吸附容量达到最大,分别为0.625和0.973mmol·g-1.在60-80℃,样品的动态吸附性能稳定.经过20次吸附-脱附循环后,样品的饱和吸附容量仅降低了6.45%.采用失活模型对CO2的吸附穿透曲线进行模拟,该模型能够很好地模拟样品对CO2的吸附过程.     

金前驱液pH值对Au-Pd/SiO2催化剂上噻吩加氢脱硫活性的影响

考察了金前驱液的pH值对Au-Pd/SiO2双金属催化剂用于噻吩加氢脱硫反应活性的影响,应用N2吸附,X-光粉末衍射(XRD)、程序升温还原(TPR)等技术对该催化剂的物性与结构进行了表征.发现当金前驱液的pH值为7时制得的双金属催化剂具有较好的加氢脱硫活性,并具有最小的孔径,该催化剂以PdO相与Au0相共存.与Pd/SiO2催化剂相比,Au-Pd/SiO2催化剂的稳定性明显提高.虽然AuxPdy合金相的生成对提高双金属催化剂的脱硫活性不利,但能明显改善催化剂的抗硫中毒能力.     

介孔TiO2对溶菌酶吸附的动力学和热力学

773.15 K下焙烧二钛酸(H₂Ti₂0₅)制备了介孔结构TiO₂。采用比表面分析仪(BET)、扫描电镜(SEM)、拉曼(Raman)光谱和X射线衍射(XRD)仪进行表征研究了介孔TiO₂对溶菌酶的吸附行为和机理。结果表明,该吸附过程较好地满足Langmuir吸附模型;随着溶液pH值的增高,溶菌酶在介孔TiO₂上的吸附量先增大后减小。在pH = 7.2时,达到最大吸附容量72.5 mg·g^-1。该介孔TiO₂对溶菌酶具有良好的吸附稳定性,经过5次循环后吸附的溶菌酶残余量仍有81.6%。动力学研究表明,介孔TiO₂与溶菌酶间的吸附满足准二级动力学模型,吸附传质过程由膜扩散和粒内扩散共同影响与控制。对热力学参数的计算发现,该过程ΔG⁰ < 0, ΔH⁰ > 0, ΔS⁰ > 0,表明介孔TiO₂对溶菌酶的吸附是一个自发的、吸热的熵增过程。     

SO4^2—／TiO2—SiO2固体超强酸的结构及其光催化性能

自从 Arata等 [1]首次报道无卤素型 SO2 - 4/Mx Oy 固体超强酸体系以来 ,对该类催化剂的研究引起了人们的广泛重视 .大量研究工作表明 ,固体超强酸催化剂对丁烷异构化、苯衍生物烷基化、链烷烃裂解和乙烯二聚等诸多酸催化的反应表现出极高的反应活性 [2 ] .最近 ,我们把 SO2 - 4/Ti O2 型固体超强酸应用于有机物的光催化氧化反应 ,研究发现 Ti O2 光催化剂经 H2 SO4 浸渍处理形成固体超强酸后 ,催化剂的光催化活性大大提高 ,并具有很好的反应活性、稳定性和抗湿性能 [3] ;此外 ,我们以前的工作表明 Ti O2 中引入 Si O2 后 ,其结构、…     

无序介孔硅复合纳米结构的制备与慢活化行为

通过对SiO_2纳米粒子进行镁热还原及后处理,制备了多级无序Si介孔复合纳米结构MP-Si@SiO_x@C,此结构展现出容量非衰减缓升的电化学慢活化行为,可抵消循环容量常规衰减趋势,赋予负极优良的循环稳定性.通过X射线衍射(XRD)、透射电子显微镜(TEM)、场发射扫描电子显微镜(SEM)、N_2吸附-脱附测试和孔径分布模拟分析发现,Si介孔组织包含微-窄介孔(1~5 nm)、中介孔(5~20 nm)以及大介孔-宏孔(20~100 nm)三级孔道,分别源于原初级粒子内部孔道、粒子团聚堆垛与粒内酸蚀、团聚体再堆垛;此合成装配方法有效提升了Si材料的堆积密度,电池电极能获得较高的体积比容量和储能密度.     

Fabrication of highly crystalline covalent organic framework for solid-phase extraction of three dyes from food and water samples

Herein, a covalent organic framework, which was fabricated at room temperature by using 1,3,5-tris(p-formylphenyl) benzene and 1,3,5-tris(4-aminophenyl)benzene as building blocks, was employed as an adsorbent for solid-phase extraction of dyes including congo red, methyl blue and direct red 80 for the first time. The prepared covalent organic framework was properly characterized by different techniques and the results revealed that it had a uniform spherical structure, high crystallinity, satisfactory surface area, and good thermal stability. Moreover, the adsorption performance of the material was explored by using static and dynamic adsorption experiments and the results indicated that the material showed good adsorption capacities for three dyes with adsorption capacities in the range of 55.25–284.10 mg/g and the adsorption equilibrium can be achieved in 15 min. Further, to achieve the best adsorption effects of the material, the influence parameters such as pH, ionic strength, type of desorption solvent, and the material dosage in the solid-phase extraction column, were optimized in turn. Finally, under optimal conditions, the solid-phase extraction coupled with HPLC was applied to the analysis of dyes in food and water samples. The recoveries of dyes in actual samples were satisfactory, revealing the unique applicability of the material in the sample pretreatment field.     

Alkali metal cation doping of metal-organic framework for enhancing carbon dioxide adsorption capacity

Metal-organic frameworks （MOFs） have attracted much attention as adsorbents for the separation of CO2 from flue gas or natural gas. Here, a typical metal-organic framework HKUST-I（also named Cu-BTC or MOF-199） was chemically reduced by doping it with alkali metals （Li, Na and K） and they were further used to investigate their CO2 adsorption capacities. The structural information, surface chemistry and thermal behavior of the prepared adsorbent samples were characterized by X-ray powder diffraction （XRD）, thermo-gravimetric analysis （TGA） and nitrogen adsorption-desorption isotherm analysis. The results showed that the CO2 storage capacity of HKUST-1 doped with moderate quantities of Li＋, Na＋ and K＋, individually, was greater than that of unmodified HKUST-1. The highest CO2 adsorption uptake of 8.64 mmol/g was obtained with 1K-HKUST-1, and it was ca. 11% increase in adsorption capacity at 298 K and 18 bar as compared with HKUST- 1. Moreover, adsorption tests showed that HKUST-1 and 1K-HKUST-1 displayed much higher adsorption capacities of CO2 than those of N2. Finally, the adsorption/desorption cycle experiment revealed that the adsorption performance of 1K-HKUST-1 was fairly stable, without obvious deterioration in the adsorption capacity of CO2 after 10 cycles.     

Synthesis and Characterization of Amino-functionalized Meso-porous Silicate MCM-41 for Removal of Toxic Metal Ions

Amino-functionalized MCM-41 has been prepared by grafting amino containing functional groups onto mesoporous silicate MCM-41 and characterized by powder X-ray diffraction, N2 adsorption/desorption measurement, SEM, FT-IR, thermogravimetry and elemental analysis to confirm the ordered mesoporous structure and the functionalization of the amino groups. Sorption behavior for 18 metal ions on this sorbent has been studied and discussed.     

Alkali metal cation doping of metal-organic framework for enhancing carbon dioxide adsorption capacity

Metal-organic frameworks (MOFs) have attracted much attention as adsorbents for the separation of CO₂ from flue gas or natural gas. Here, a typical metal-organic framework HKUST-1(also named Cu-BTC or MOF-199) was chemically reduced by doping it with alkali metals (Li, Na and K) and they were further used to investigate their CO₂ adsorption capacities. The structural information, surface chemistry and thermal behavior of the prepared adsorbent samples were characterized by X-ray powder diffraction (XRD), thermo-gravimetric analysis (TGA) and nitrogen adsorption-desorption isotherm analysis. The results showed that the CO₂ storage capacity of HKUST-1 doped with moderate quantities of Li⁺, Na⁺ and K⁺, individually, was greater than that of unmodified HKUST-1. The highest CO₂ adsorption uptake of 8.64 mmol/g was obtained with 1K-HKUST-1, and it was ca. 11% increase in adsorption capacity at 298 K and 18 bar as compared with HKUST-1. Moreover, adsorption tests showed that HKUST-1 and 1K-HKUST-1 displayed much higher adsorption capacities of CO₂ than those of N₂. Finally, the adsorption/desorption cycle experiment revealed that the adsorption performance of 1K-HKUST-1 was fairly stable, without obvious deterioration in the adsorption capacity of CO₂ after 10 cycles.     

四氢呋喃聚合介孔催化剂Zr-PHTS合成、表征及反应性能

在水-有机溶剂复合体系中,以P123为结构导向剂水热直接合成了锆掺杂介孔固体酸催化剂(Zr-PHTS),运用XRD、TEM、N2吸附-脱附以及NH3-TPD、Py-FTIR等手段对催化剂进行了表征.结果表明,在硅锆摩尔比20-100考察范围内,所得Zr-PHTS样品均显示有序二维六方晶相结构,具有以L酸为主的中等强度的酸性中心;随着锆引入量的变化Zr-PHTS的比表面积仅显示少量的变化,孔径维持在9.8 nm;在四氢呋喃聚合反应中Zr-PHTS显示出较好的催化活性,硅锆摩尔比30的样品表现出最佳的催化性能,聚合物收率达到40.4%,数均分子量2 135,推测催化剂表面酸性和孔结构决定了催化剂对四氢呋喃的聚合性能.     

超临界条件下合成晶型骨架的介孔氧化锆

采用聚氧乙烯型非离子表面活性剂(PEO)为模板剂,超临界乙醇为介质,在不同条件下(各种PEO,不同pH值和络合剂)合成了类似于MSU的介孔氧化锆.XRD,N₂物理脱吸附曲线,TEM及选区电子衍射证明该介孔氧化锆骨架为四方晶型;改变表面活性剂类型、络合剂及pH可调变介孔氧化锆的BET表面积与孔分布.