用于生物气提纯的促进传递膜

由生物气提纯获得的生物甲烷具有高热值,可作为天然气的替代品。生物气中除主要成分甲烷以外还含有大量的CO2和少量的水、H2S以及其他痕量杂质组分,需经过净化提纯方可获得高纯度的生物甲烷。膜分离技术用于生物气提纯具有绿色、高效、能耗低等特点,特别地,促进传递膜因其特殊的传质机制,对于生物甲烷系统提纯具有显著优势。综述了促进传递膜材料及其制备技术,讨论了生物气中水、H2S杂质对膜过程的影响,同时尝试对膜法生物气提纯的经济性和发展前景进行了分析。     

固定白蛋白促进传递膜的制备及性能研究

以戊二醛作交联剂，固定白蛋白于常规的微波膜，制得固定白蛋白促进传递膜，并将该膜用于血浆中亲脂性毒物的消除，依据促进传递原理，建立了实验条件下的数学模型，实验结果表明，膜对亲脂性毒物有一定的消除效果，所建模型与实验结果较为吻合。     

促进传递液膜分离丙烯(Ⅰ)工艺条件

用含有AgNO3载体的支撑液膜对丙烯进行促进传质分离,研究了不同工艺条件、支撑体材料等因素对丙烯纯度、渗透速率、单程收率及选择性因子的影响．在最佳条件下,丙烯的纯度达99.3％～99.7％,单程收率5.6％,选择性因子＞700．给出了液膜稳定性处理方法．实践证明,支撑液膜促进传递过程明显优于被动的溶解-扩散过程．     

CO2通过合成聚合物膜的促进传递

Two kinds of fixed carrier membrane materials containing secondary amine and carboxyl groups whichcan be used as carriers of CO2 were prepared. One was poly(N-vinyl-γ-sodium aminobutyrate)(PVSA), whichwas obtained through the hydrolysis of polyvinylpyrrolidone (PVP) synthesized with N-vinylpyrrolidone(NVP) byradical polymerization. The other was poly(N-vinyl-γ-sodium aminobutyrate-co-sodium acrylate)(VSA-SA), whichwas obtained through the hydrolysis of copolymer of N-vinylpyrrolidone and acrylamide(AAm) (NVP-AAm). Thecomposite membranes were developed with PVSA or VSA-SA as active layer and polysulfone (PS) as supportmembranes. The permeation rates of pure CO2 and CH4 gas as well as binary mixtures of CO2/CH4 throughthe composite membranes were measured. The results show that the composite membranes present better CO2permeation rates than other fixed carrier membranes do reported in literature. For example, at 26℃, 1330 Pa of CO2pressure, the PVSA/PS composite membrane displays a CO2 permeation rate of 5.95 × 10-7 cm3.cm-2.s-1.pa-1with CO2/CH4 ideal separation factor of 212.1. At 20℃, 6400Pa of CO2 pressure, the VSA-SA/PS compositemembrane displays a CO2 permeation rate of 4.24 × 10-8 cm3@cm-2.s-1.Pa-1 with CO2/CH4 ideal separationfactor of 429.7. The results with the gas mixtures are not as good as those obtained with pure gas because ofthe coupling effects between CO2 and CH4. The heat cross-linked membrane shows good separation factor due todensification of the polymer.     

促进传递液膜分离丙烯(Ⅱ)数学模型

基于载体Ag~+与丙烯发生瞬时可逆反应的事实,根据传质理论,推出了简化的促进传递液膜分离丙烯的传质模型,并通过实验数据回归,得出了两种不同支撑体时的模型参数,所得结果验证了模型的正确性．     

仿生促进杂化膜的制备及其性能研究

基于人工肺(ECMO)与血液直接接触,提出利用生物相容性良好的材料制备仿生促进杂化膜用于ECMO.在聚醚砜超滤膜上涂覆聚甲基丙烯酸甲酯作为分离层,氧栽体选用钴卟啉与咪唑配位的仿血红素结构,制备了一种仿生促进杂化膜,重点考察其在低压环境下对氧气/二氧化碳及氧气/氮气的分离性能.气体渗透性测试结果表明:当聚甲基丙烯酸甲酯(PMMA)质量分数为4.6％、四苯基钴卟啉质量分数为0.460％、压力为0.012 MPa时,制备的CoTPP-PMMA-PES复合膜分离性能较好,此时膜厚度为0.92 μm.与PMMA-PES复合膜相比,氧气渗透速率由8.05 GPU升至21.25 GPU,氧气/氮气选择性由1.28升至2.66,氧气/二氧化碳选择性由0.70升至0.92.     

化学作用强化的膜过程

本文对近年来关化学作用强化的膜过程研究进行了评述；介绍了促进传递、耦合传递及电化学泵等过程；讨论了利用化学作用强化的膜过程研究中若干带有共性的问题。     

浸没式膜生物反应器技术用于废水的现场深度处理及回用

人们愈加认识到废水随意排放的后果和对新鲜水短缺应负的责任。因此，将废水处理到可回用的水质已成为水处理的最关键问题之一。虽然在许多地区浸没式膜生物反应器（IMBR）技术在废水深度处理使之达到回用标准中的应用仍属于一种较新的方法，然而在整个北美和欧洲却广泛应用了十多年。     

氯碱离子膜的水传递和水通量

水传递对氯碱离子膜的电化学性能有重要的影响,而膜内水传递过程是电解过程的重要环节。在计算氯碱装置的宏观水通量的基础上,讨论了水传递现象对氯碱离子膜的电化学性能的影响,提出膜的离子透过性赋予膜以电导性,而离子的水传递数决定了氯碱膜的水通量大小。简要介绍了国产氯碱离子膜的基本结构和应用进展,展望了氯碱膜的发展前景。     

动态膜生物反应器用于污水处理的研究进展

动态膜生物反应器是近年来发展起来的高效废水处理工艺。该文介绍了国内外动态膜生物反应器的膜基材和动态膜的种类、形成机理,影响动态膜生物反应器过滤性能的因素,动态膜的清洗方法;并对今后的研究方向作了展望。     

Phosphorylated nanocellulose fibrils/PVA nanocomposite membranes for biogas upgrading at higher pressure

ABSTRACT

High moisture uptake and excellent mechanical properties of cellulose nano-fibril (CNF) make it an interesting material to use as an additive in facilitated transport membranes. The objective of this work is to develop novel phosphorylated nanocellulose fibrils (PCNF)/polyvinyl alcohol (PVA) nanocomposite membranes for biogas upgrading. Results showed that the thickness of membrane increases with increasing concentration of PCNF. The addition of PCNF to pristine PVA membranes has beneficial effect for CO₂/CH₄ separation. However, maximum performance was achieved with 1 wt.% PCNF in 2% PVA at pH 12. Furthermore, increasing feed pressure caused a decrease in both permeability and selectivity.     

Facilitated transport of benzylpenicillin through immobilized liquid membrane

The rate of benzylpenicillin transport, as an ionic pair with a tetrabutyl ammonium cation, from aqueous media through a liquid membrane consisting of n-decanol supported in a porous Teflon membrane has been investigated as a function of the chemical composition of the system and the hydrodynamic conditions at 25°C. The measured transfer rates have been explained in terms of the diffusion of the ionic pair species through the liquid membrane. The results are in agreement with theoretical predictions and it is demonstrated that the transport of benzylpenicillin takes place against a concentration gradient.     

Facilitated transport of ethyl docosahexaenoate through solution-cast perfluorosulfonated ionomer membranes

The facilitated transport of ethyl docosahexaenoate (DHA-Et) through the thin solution-cast perfluorosulfonated ionomer membranes has been studied. The carrier of DHA-Et was silver ion and was immobilized in the support ionomer membrane by electrostatic forces. In this system, the feed phase, membrane phase, and receiving phase had the same solvent. This system was already proved to be highly stable in our previous work. When ethanol/water (85/15) was used as the solvent, the DHA-Et permeance in the cast membrane was about four times higher than that in the commercial Nafion® 117 membrane, due to the smaller membrane thickness. In the case of acetone solvent, a high selectivity of DHA-Et to ethyl oleate of 42 and a high facilitation factor of 153 were obtained. These membrane performances were superior to those of the Nafion® 117 membrane. The effects of membrane preparation conditions, such as annealing temperature and kinds of polar solvents added to the ionomer solution before annealing, on the membrane performance was investigated in detail. Furthermore, small-angle X-ray scattering (SAXS) measurement was carried out to study the membrane structure. The experimental result suggests higher crystallinity in the cast membrane annealed at higher temperature. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 961–968, 1999     

Facilitated oxygen transport in a novel silicone polymer membrane containing carboxylic cobalt groups

A novel silicone polymer membrane with facilitated oxygen transport properties was prepared by using 11‐alkene acid cobalt, a silicone rubber containing vinyl groups of 5 mol %, a hydrogen‐containing silicon oil, and chlorine platinum acid. The solution casting and the vulcanization were carried out simultaneously at room temperature. Investigation showed that PO ₂ increased and PN ₂ did not change with decreasing gas pressure difference. This facilitated oxygen transport behavior was contributed by a polymeric cobalt complex formed from carboxylic groups and cobaltous ions in the membrane to result in the simultaneous increase of both PO ₂ and αO ₂/N ₂ under lower gas pressure difference. For example, the PO ₂ and αO _2/N ₂ of the membrane containing 11‐alkene acid cobalt of 2.5 wt% were 750 Barrer and 3.09 under a gas pressure difference of 0.05 mPa. As much as 5 wt% 11‐alkene acid cobalt could be added to the membranes; PO ₂ and αO _2/N ₂ increased to 802 Barrer and 3.34 respectively when the membrane contained 11‐alkene acid cobalt of 5 wt %. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1038–1044, 2003     

Facilitated transport of oxygen in ethyl cellulose membranes containing cobalt porphyrins as oxygen carriers

Facilitated transport of oxygen was investigated in ethyl cellulose membranes containing cobalt(II) meso‐tetrakis (substituted phenyl) porphyrins [CoTPP, CoT(2‐Cl)PP, CoT(4‐Cl)PP, CoT(4‐MeO)PP, and CoT(2,4‐2MeO)PP] as fixed oxygen carriers. The oxygen permeability (P) and oxygen/nitrogen selectivity (P/P) of the membranes containing oxygen carriers increase with a decrease in the upstream gas pressure, but the nitrogen permeability (P) is almost independent of the upstream nitrogen pressure. This indicates that the fixed oxygen carriers in the polymer membranes can reversibly interact with oxygen and facilitate oxygen transport in the membranes. The study on the influences of the substituents in the cobalt(II) porphyrins and the fifth ligand (imidazole or pyridine) on the membrane permeation behaviors shows that the porphyrin complex with an electron‐accepting substituent in the meso‐phenyl ring or with imidazole as the fifth ligand could increase the permeability and oxygen/nitrogen selectivity of the membranes much more than that with an electron‐donating substituent or with pyridine as the fifth ligand. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 484–488, 2000     

固定载体促进传递研究进展

固定载体促进传递是兼具高通量和高选择性的膜分离技术. 本文分析了国内外的研究现状，综述了固定载体促进传递的机理，讨论了载体固定化的方法，指出了目前需要解决的问题并对其发展前景作了预测.     

Facilitated oxygen transport through a Nafion membrane containing cobaltporphyrin as a fixed oxygen carrier

A Nafion membrane containing a cobaltporphyrin (CoP) complex as a fixed oxygen carrier was prepared with a view to facilitate oxygen transport through the membrane. The design concept of the CoP-loaded Nafion membrane was based on the CoP's modification to place the CoP complex in a hydrophobic domain of the microphase-separated structure, in order to facilitate the oxygen transport and to maintain proton conductivity. The oxygen permeability through the CoP-loaded Nafion membrane was higher than the nitrogen permeability, and significantly enhanced at relatively-low oxygen pressures of the upstream, indicating that the fixed CoP complex acted as an oxygen hopping site to facilitate the oxygen transport. The oxygen/nitrogen permselectivity increased with the content of CoP in the Nafion membrane. Electrochemical reduction of oxygen at a glassy carbon electrode, modified with a Pt/C catalyst and the CoP-loaded Nafion membrane, provided additional support for the facilitated oxygen transport by the membrane. Increased current for the reduction of oxygen on the modified electrode by loading CoP indicated that the CoP offered the oxygen hopping site in the Nafion membrane.     

利用外源氢气纯化升级沼气的研究进展

沼气发酵过程存在产气速率低和甲烷浓度低两个普遍问题。从甲烷生成的反应机理来看,如果提供充足的氢气,能够把沼气中的CO₂成分转化为CH₄,既提高了甲烷的产量,又提高了甲烷的浓度。介绍了最近国内外在这个方向上的探索性研究成果。实验表明,利用外源氢气确实可以纯化升级沼气,在一定条件下还可以达到生物甲烷的品质（即CH₄浓度高于95%）。分析了这项技术实用化需要解决的两个关键问题：强化H₂气液传质及获取廉价氢源。最后,对这个方向进行了展望,并提出了一个光电催化产氢与厌氧发酵产甲烷耦合的设想方案。     

Recent developments in fuel‐processing and proton‐exchange membranes for fuel cells

In recent years, great progress has been made in the development of proton‐exchange membrane fuel cells (PEMFCs) for both mobile and stationary applications. This review covers two types of new membranes: (1) carbon dioxide‐selective membranes for hydrogen purification and (2) proton‐exchange membranes; both of these are crucial to the widespread application of PEMFCs. On hydrogen purification for fuel cells, the new facilitated transport membranes synthesized from incorporating amino groups in polymer networks have shown high CO₂ permeability and selectivity versus H₂. The membranes can be used in fuel processing to produce high‐purity hydrogen (with less than 10 ppm CO and 10 ppb H₂S) for fuel cells. On proton‐exchange membranes, the new sulfonated polybenzimidazole copolymer‐based membranes can outperform Nafion^® under various conditions, particularly at high temperatures and low relative humidities. Copyright © 2010 Society of Chemical Industry     

CO2通过合成聚合物膜的促进传递

Two kinds of fixed carrier membrane materials containing secondary amine and carboxyl groups which can be used as carriers of CO2 were prepared. One was poly(N-vinyl-7-sodium aminobutyrate)(PVSA), which was obtained through the hydrolysis of polyvinylpyrrolidone (PVP) synthesized with N-vinylpyrrolidone(NVP) by radical polymerization. The other was poly(N-vinyl-7-sodium aminobutyrate-co-sodium acrylate)(VSA-SA), which was obtained through the hydrolysis of copolymer of N-vinylpyrrolidone and acrylamide(AAm) (NVP-AAm). The composite membranes were developed with PVSA or VSA-SA as active layer and polysulfone (PS) as support membranes. The permeation rates of pure CO2 and CH4 gas as well as binary mixtures of CO2/CH4 through the composite membranes were measured. The results show that the composite membranes present better CO2 permeation rates than other fixed carrier membranes do reported in literature. For example, at 26℃, 1330 Pa of CO2 pressure, the PVSA/PS composite membrane displays a CO2 permeation