MFI型分子膜的制备与H2S/CH4分离性能

采用二次生长法在多孔α-Al₂O₃载体上制备MFI型（ZSM-5和silicate-1）分子筛膜;通过XRD和SEM检测,证明所合成的分子筛膜为致密、交联和无取向的MFI型分子筛膜,厚度为5 μm;单组分气体渗透实验检测中,所制备样品膜的N₂渗透量均小于10^-11 mol/（m²·s·Pa）,可认为其无缺陷;同时,考察了样品分子筛膜对H₂S/CH₄混合气的分离效果,在渗透压分别为0.3和0.5 MPa时,silicate-1分子筛膜的H₂S/CH₄的分离因子分别为1.99和4.44,而ZSM-5分子筛膜的CH₄/H₂S的分离因子分别为6.71和12.85。     

SIFSIX-3-Ni膜的制备及氢气分离性质

利用(NH₄)₂SiF₆修饰大孔玻璃基底后, 在溶剂热条件下制备了SIFSIX-3-Ni膜, 并研究了温度和浓度对制备SIFSIX-3-Ni膜的影响. 能谱分析(XPS)结果表明大孔玻璃表面引入了氟元素. SIFSIX-3-Ni膜的粉末X射线衍射(PXRD)峰位置和模拟结果一致, 表明成功制备出SIFSIX-3-Ni膜. 从扫描电子显微镜(SEM)照片中观察到膜连续均匀, 厚度约为20 μm. 热重分析(TGA)结果表明, 活化前的膜没有客体分子. 单组分测试结果表明, 膜的H₂, CO₂和N₂渗透量分别为6.83×10 ^-6, 7.42×10 ^-7和8.89×10 ^-7 mol·m ^-2·s ^-1·Pa ^-1, H₂/CO₂和H₂/N₂的理想分离比分别为9.20和7.68. 在连续测试5 h后, H₂, CO₂和N₂渗透量基本保持不变, 表明SIFSIX-3-Ni膜具有很好的稳定性.     

高性能AlPO4-14分子筛膜的制备及气体分离性能

制备了高性能的AlPO₄-14分子筛膜. 首先通过控制反应溶胶中水和模板剂的含量制备了形貌均一的AlPO₄-14分子筛, 分子筛的尺寸为15~18 mm; 然后采用晶种法即在反应凝胶中加入分子筛作为晶种进一步调控分子筛的大小, 使得AlPO₄-14分子筛的尺寸从15~18 mm减小到2~3 mm, 得到形貌均一的纯相片状晶体, 同时有效缩短了制备时间; 最后以多孔管状莫来石为支撑体, 采用二次生长法制备AlPO₄-14分子筛膜. 考察了2种不同大小的晶种对膜形貌和性能的影响, 发现以大尺寸的分子筛(15~18 mm)作为晶种制备的分子筛膜的分离层存在较多缺陷, 而采用小尺寸的晶种(2~3 mm)制备的膜层较均一致密. AlPO₄-14分子筛膜经高温脱除模板剂后仍然保持着纯相的AlPO₄-14晶型, 表明二次生长法促进了AlPO₄-14晶体在膜层中的生长且使其具有更高的结晶度和热稳定性. 在25 ℃, 100 kPa下, AlPO₄-14分子筛膜对H₂/CH₄, CO₂/CH₄和H₂/CF₄的理想分离因子分别为28, 40和1047, 且H₂和CO₂的渗透速率分别为6.3×10 ^-7和9×10 ^-7 mol·(m ²·s·Pa) ^-1; 对等摩尔CO₂/CH₄混合气体的分离因子为81.5, 且CO₂的渗透速率为8.8×10 ^-7 mol·(m ²·s·Pa) ^-1.     

三氟丙基修饰的有机-无机杂化二氧化硅膜制备、氢气分离及水热稳定性能

以三氟丙基三甲氧基硅烷(TFPTMS)和1,2-双(三乙氧基硅基)乙烷(BTESE)为前驱体, 通过溶胶-凝胶法在酸性条件下制备三氟丙基修饰的有机-无机杂化SiO₂膜材料, 并深入研究三氟丙基修饰对溶胶粒径和疏水性能的影响以及膜材料的氢气渗透分离性能和长期水热稳定性. 结果表明三氟丙基已成功修饰到有机-无机杂化SiO₂膜材料中, 且随着TFPTMS修饰量的增加, 溶胶粒径有减小趋势, 膜材料的疏水性能逐渐提高. 当n(TFPTMS)/n(BTESE)＝0.6时, 溶胶平均粒径为2.11 nm, 膜材料对水的接触角达到111.6°±0.7°. H₂在修饰后膜材料中的输运主要遵循微孔扩散机理, 300 ℃时H₂的渗透率为8.86×10^-7 mol·m^-2·s^-1·Pa^-1, H₂/CO₂的理想分离系数达到5.4, 且当进气摩尔比例为1∶1时H₂/CO₂的双组分气体分离系数达到了4.82, 均高于Knudsen扩散分离因子(H₂/CO₂＝4.69), 膜材料呈现出良好的分子筛分性能. 膜材料在250 ℃及水蒸气摩尔含量为5%的水热环境中能稳定工作300 h以上.     

基于拮抗作用检测除草剂的类囊体膜生物传感器研究

利用除草剂对植物类囊体束缚酶分解过氧化氢的拮抗作用,研制了一种快速检测痕量除草剂的电化学生物传感器.将植物类囊体用聚乙烯醇-苯乙烯吡啶(PVA-SbQ)光敏聚合剂在紫外光诱导下产生大分子网状结构进行包埋,制成生物敏感膜,并固定在铂电极表面.根据加入除草剂时类囊体膜束缚酶分解过氧化氢活性的变化,对除草剂进行测定.在含有1×10^-3mol/LNaCl,5×10^-3mol/LMgCl₂和0.01mol/LH₂O₂的Tris-HCl缓冲溶液(pH=7.4)中,基于测量0.65V处H₂O₂氧化电流的变化,可以对下列浓度的除草剂进行定量检测:百草枯3×10^-9～1.5×10^-7mol/L,敌草龙1×10^-8～3×10^-7mol/L,扑草净4×10^-8～3×10^-6mol/L,阿特拉津1×10^-7～5×10^-6mol/L,莠灭净1×10^-7～5×10^-6mol/L.利用PVA-SbQ光聚合膜固定类囊体,能够使酶的活性在低温下保持数月.     

十七氟癸基修饰的有机-无机杂化二氧化硅膜材料的制备及气体分离性能

以十七氟癸基三乙氧基硅烷(PFDTES)和1,2-双(三乙氧基硅基)乙烷(BTESE)为前驱体, 通过溶胶-凝胶法制备了十七氟癸基修饰的SiO₂溶胶, 采用浸渍提拉法在γ-Al₂O₃/α-Al₂O₃多孔陶瓷支撑体上涂膜, 然后在N₂气氛保护下烧结成完整无缺陷的有机-无机杂化SiO₂膜. 利用扫描电子显微镜对膜材料的形貌进行观察, 通过动态光散射技术对溶胶粒径及分布进行测试, 利用视频光学接触角测量仪、 红外光谱仪和热分析仪表征了十七氟癸基修饰对有机-无机杂化SiO₂膜疏水性的影响. 结果表明, 十七氟癸基已经成功修饰到SiO₂膜材料中, 且随着PFDTES加入量的增大, 溶胶粒径和膜材料对水的接触角不断增大. 当n(PFDTES): n(BTESE)=0.25: 1时, 溶胶粒径分布较窄, 平均粒径为3.69 nm, 膜材料对水的接触角为(112.0±0.4)º. 在修饰后的有机-无机杂化SiO₂膜中H₂的输运遵循微孔扩散机理, 在300℃时, H₂的渗透率达到5.99×10^-7 mol·m^-2·Pa^-1·s^-1, H₂/CO和H₂/CO₂的理想分离系数分别达到9.54和5.20, 均高于Knudsen扩散的理想分离因子, 表明膜材料具有良好的分子筛分效应.     

基于Nafion固定磷钼酸和石墨烯共修饰PEDOT膜电极的电化学过氧化氢传感器

以玻碳电极（GCE）为基底电化学聚合制得聚3,4-乙烯二氧噻吩（PEDOT）膜修饰电极,再通过Nafion共固定磷钼酸和石墨烯构建了一种新型的无酶电化学H₂O₂传感器. 利用扫描电子显微镜（SEM）表征制得的修饰电极,并通过循环伏安法和计时电流法研究了传感器对H₂O₂的响应性能. 结果表明,在优化条件下,该传感器对H₂O₂还原具有良好的电催化性能,检测H₂O₂的线性范围为2.91×10^-6 ~ 1.83×10^-2 mol•L^-1,检出限和灵敏度分别为9.90×10^-7 mol•L^-1（S/N = 3）和112.5 μA•（mmol•L^-1）^-1. 此外,该传感器还具有良好的重现性和选择性.     

溶胶-凝胶法制备硅系有机-无机杂化分离膜

以α-Al₂O₃多孔陶瓷片为载体,用溶胶-凝胶法制备有机-无机杂化分离膜.通过考察前驱物的组成及杂化溶胶的合成条件对制膜工艺过程的影响,得到了制备有机-无机杂化分离膜的各种适宜性参数.红外光谱(FTIR)分析结果表明,杂化溶胶的性能不仅决定分离膜的性能,而且对膜热处理过程中的龟裂有很大影响.膜层的厚度为1～2μm;在膜两侧压差为0.10MPa、n(PTMOS)/n(TEOS)=1.16时,膜对O₂/N₂,CO₂/N₂和CO₂/O₂的分离因子分别为2.30,4.31和1.17,渗透系数为75.81×10^-17,75.28×10^-17和72.78×10^-17m₃(STP)·m/(m₂·s·Pa).     

纳米ZrO2在O2/H2气中的表面效应

用ESR方法研究了一种纳米ZrO₂在普通H₂气中升温条件下的表面效应.ZrO₂上Zr³⁺的中心量约为1×10^-7mol/g.这些Zr³⁺中心是ZrO₂表面一些O^2-配位不饱和的Zr原子点位.在普通H₂气中,ZrO₂上的Zr³⁺中心数在温度低于400℃时变化很小.但在这一温度范围内从室温升温时,由ZrO₂表面羟基的H₂还原引起的F中心量随温度的升高而增加.温度高于400℃时,ZrO₂表面的Zr³⁺及F中心可与普通H₂气中存在的少量O₂气作用产生O₂^-,并伴随ZrO₂表面羟基的脱除而形成新的Zr³⁺.     

孔雀石绿分子印迹膜的制备和渗透性

以0.45 μm混合纤维素酯微孔膜为支载膜,丙烯酰胺为功能单体,N, N'-亚甲基双丙烯酰胺为交联剂,通过原位聚合法制备得到孔雀石绿分子印迹膜,并研究了其对模板分子和类似物的渗透性能。以分子印迹膜作为渗透膜,单一渗透实验中,13 h后MG的渗透量达到0.118×10^-3 g/cm²,而相同时间内甲基紫、甲酚红和溴百里酚蓝的渗透量分别为0.064×10^-3、0.057×10^-3和0.044×10^-3 g/cm²,且在竞争渗透中孔雀石绿的渗透速率没有发生明显变化,而甲基紫的渗透速率却显著下降。实验表明,分子印迹膜对模板分子孔雀石绿表现出良好的渗透选择性,且在与类似物甲基紫的竞争渗透中具有优先渗透能力。     

堇青石栽体表面ilicalite-1沸石膜的合成与表征

本文首次采用堇青石为载体,用水热合成方法,制备了致密的高硅MFI沸石膜,并对其结构、成分以及气体渗透性质进行表征。     

Fabrication of polymer/fluoride-containing salts blend composite membranes for CO2 separation

Poly (N, N-dimethylaminoethyl methacrylate)-poly (ethylene glycol methyl ether methacrylate) (PDMAEMA-PEGMEMA) and cesium fluoride (CsF) were blended and used as the separation material of composite membranes. Hollow fiber composite membranes were fabricated by coating the blend on polysulfone (PSf) hollow fiber substrate. Introduction of fluorine ion improved the separation performance of the membrane. The concentration of coating solution was adjusted to obtain a membrane with high permeance. The composite membrane showed good performance with the CO2 permeance of 30.4 GPU (1 GPU = 10^-6 cm³(STP)/(cm²·s·cmHg)), and selectivities to CO2/N2, CO2/CH4, CO2/H2 and O2/N2 of 47.2, 37.6, 1.75 and 4.70, respectively. Potassium fluoride (KF), due to its low cost, was also used as a substitute of CsF to prepare composite membrane and the permeation data showed that CsF can be replaced by KF. The effect of operating temperature on the permeation properties of the composite membrane was also investigated.     

一种气相合成Silicalite-1沸石膜的新方法

由于在分离和催化领域的潜在应用前景 ,沸石膜近年来受到人们的广泛重视 .制备沸石膜的方法很多 ,如原位水热合成、微波合成、电金属沉积、嵌入法等等 .90年代以来 ,由于可减少昂贵的模板剂用量 ,以及能在不同载体上合成沸石膜等优点 ,蒸汽相合成法 (ＶＰＴ)受到关注[1 3] .通常采用浸渍方法或正硅酸乙酯 (ＴＥＯＳ)的水解在载体上形成一层致密的无定形凝胶作为引入的硅源 ,随即在有机模板剂和水的蒸汽相中转晶得到沸石膜 .自 1 992年Ｄｏｎｇ等[1 ] 首先采用ＶＰＴ方法合成ＺＳＭ 5和ＺＳＭ 35沸石膜以来 ,已经成功制备了多种结构类型的沸…     

澄清溶液中NaA型分子筛膜的合成及气体渗透性能

The use of zeolite membranes in separation or combined reaction and separation processes is very attractive. Advantages of using such a type of membranes include their ability to discriminate molecules based on the molecular size and their stability[1]. In the past ten years, most efforts were involved in the synthesis and permeation studies of MFI zeolite membrane[2, 3]. Recently, NaA zeolite membrane has attracted much attention because of its high potential in the dehydration of organic liquids[4]. However, few gas permeation results were reported[5]. Furthermore, most of the NaA zeolite membrane was synthesized from gel[4]. In this letter, the synthesis of NaA zeolite membrane from clear solution and its gas permeation properties are reported.     

有机功能化α-Al2O3陶瓷中空纤维表面合成高性能分离氢用NaA分子筛膜

通过浸渍3-氨丙基甲基二乙氧基硅烷(ADMS)对α-Al₂O₃中空纤维载体进行有机功能化改性, 使载体表面带正电, 利用NaA分子筛晶种负电性与功能化载体之间的静电吸附机理进行预涂晶种, 采用微波加热-二次生长法于载体表面合成了NaA分子筛膜. 采用X射线衍射(XRD)、zeta 电位、扫描电子显微镜(SEM)等分析手段和气体渗透实验对NaA分子筛膜进行了表征. 考察了未改性NaA分子筛膜与改性NaA分子筛膜的形貌、结构和气体渗透性能差异. XRD结果表明载体表面只有NaA分子筛生成; zeta 电位分析表明NaA分子筛晶种及分子筛前驱体与有机功能化载体电位相反, 存在静电吸附作用; SEM结果显示改性NaA分子筛膜表面颗粒相互联结呈孪生态, 膜厚约5 μm, 膜层致密、均匀、平整; 在不同温度下对H₂、O₂、N₂和C₃H₈进行气体渗透测试,35 °C条件下改性NaA分子筛膜对H₂的渗透率仅为3.6×10^-7 mol·m^-2·s^-1·Pa^-1, 较未改性NaA分子筛膜的渗透率(4.0×10^-7 mol·m^-2·s^-1·Pa^-1)低, 而改性NaA分子筛膜的H₂/C₃H₈理想分离系数则高达11.25, 远大于未改性NaA分子筛膜的H₂/C₃H₈理想分离系数(5.06).     

Synthesis Optimization of SSZ-13 Zeolite Membranes by Dual Templates for N2/NO2 Separation

High-silica SSZ-13 zeolite membranes are promising in industrial separations of light gases and continuous membranes are highly demanded for better separation performances. Herein, pure-phase, continuous and thin SSZ-13 zeolite membranes were synthesized using dual templates of N,N,N-trimethtyl-1-adamantammonium hydroxide(TMAdaOH) and tetraethylammonium hydroxide(TEAOH). Systematical investigations of TMAdaOH/TEAOH ratios and their concentrations show that TMAdaOH acts as the main structure-directing agent in the formation of the SSZ-13 zeolite. TMAdaOH cooperatively plays with TEAOH in promoting the SSZ-13 crystal intergrowth to form a continuous polycrystalline membrane. Additionally, appropriate introduction of TEAOH is able to adjust the membrane thickness to the crystal-comparable size of ca. 2.0 μm. The SSZ-13 membranes are further applied for N₂/NO₂separation, which is firstly reported on zeolite membranes. The gas permeation results show that the SSZ-13 membrane synthesized by the dual-template approach exhibits selective separation of N₂ over NO₂ with N₂/NO₂ separation factor of 7.6 and N₂ permeance of 1.66×10^-8 mol·m^-2·s^-1·Pa^-1.     

PREPARATION OF SILICALITE-1 AND ZSM-5 ZEOLITE/ CERAMIC COMPOSITE MEMBRANES

ＰＲＥＰＡＲＡＴＩＯＮＯＦＳＩＬＩＣＡＬＩＴＥ┐１ＡＮＤＺＳＭ┐５ＺＥＯＬＩＴＥ／ＣＥＲＡＭＩＣＣＯＭＰＯＳＩＴＥＭＥＭＢＲＡＮＥＳＺｈａｎｇＬｉｘｉｏｎｇ，ＪｉａＭｅｎｇｄｏｎｇ，ＭｉｎＥｎｚｅ（ＲｅｓｅａｒｃｈＩｎｓｔｉｔｕｔｅｏｆＰｅｔｒｏｌｅ...     

气体分离分子筛膜

本文简述了气体分离分子筛膜的研究进展,总结了气体分离分子筛膜的制备方法、分子筛膜类型、气体分离性能及催化应用,分析了气体渗透测定方法和分离机理,对分子筛膜的发展提出一些建议。     

Gas-permeation continuous flow coulometric analysis: determination of sulphur dioxide

 A gas permeation system using two gaseous streams flowing on both sides of a membrane is developed. This gas permeation device and a coulometric detector are adapted for the continuous measurement of relatively high concentrations of sulphur dioxide. The interferences of other gases (NO₂, NO and CO₂) can be eliminated by using a scrubber behind the gas permeation device in the acceptor stream. The effects of the donor flow rates and gas pressure as well as the membrane thickness on the signal are discussed. The relative standard deviation is 1.3% (n=7) for 2.002×10^-3 mol/mol certified sulphur dioxide. Received: 19 July 1996/Revised: 22 October 1996/Accepted: 29 October 1996     

Role of clay-based membrane for removal of copper from aqueous solution

The present study focuses on the fabrication of polysulfone (PSf)-clay minerals impregnated hybrid membrane for treatment of Cu (II) ions. Blending and phase inversion methods have been employed to develop clay-based membranes by the mixing of bentonite, sepiolite and zeolite in the matrix of PSf. Moreover, characterization of fabricated membranes was carried out using SEM, FTIR, zeta potential, pore size and water contact angle measurement. Adsorption and filtration experiments were conducted to evaluate the permeation performance of the membrane. Obtained results of permeation study reveal that the presence of clay minerals in the matrix of modified membrane not only increases the adsorption and rejection efficiency for Cu (II) but, it also improves the flux of pure water. Among all developed membranes, the membrane prepared by the mixing of zeolite demonstrates the highest adsorption (2.82 mg/g) and rejection value (97%) towards Cu (II) at low pressure (0.5 bar). Regeneration performance results confirm the reusability of membrane up to 3–5 cycles along with 82.5–90% metal recovery. Based on significant metal recovery, clay-based low-cost zeolite/PSf membrane could be used to remove Cu (II) from water at low pressure to replace current conventional membrane.