Armos/聚砜共混中空纤维基膜及其纳滤复合膜的制备与性能研究

中空纤维膜因其体积装填密度高、占地面积小、成本相对低等优点备受关注。本文通过将Armos聚合液与聚砜(PSf)共混，经干-湿法纺丝制备了Armos/PSf共混中空纤维超滤膜，研究表明：Armos均匀分散在中空纤维膜中，中空纤维膜断面呈现疏松的多孔结构，随着Armos共混含量的增加，膜的亲水性和纯水通量均提高，但对PEG-20000截留率下降明显。以Armos/PSf共混中空纤维膜为基膜，通过界面聚合制备了中空纤维复合纳滤膜，优化的制备条件为：基膜中Armos的共混含量为4%、水相单体浓度为3%、油相单体浓度为0.15%时，制得的中空纤维复合纳滤膜性能最佳，其通量为8.40L/(m²·h)，对MgSO₄的截留率为88%。     

核壳结构Ziegler-Natta复合催化剂的制备及其乙烯聚合

采用溶胶-凝胶法,将聚(苯乙烯-co-丙烯酸)(PSA)膜材料和氯化镁的复合物包覆在以硅胶为载体的TiCl3催化剂上,负载TiCl4后制得Ziegler-Natta复合催化剂.采用红外光谱、激光粒度仪和扫描电镜对催化剂进行了表征,结果表明该复合催化剂呈核壳结构.同时,考察了复合催化剂中膜的厚度和反应中的氢气含量对催化剂的聚合活性和聚乙烯性能的影响,实验发现,膜厚约为3μm的核壳结构复合催化剂活性良好,其具有带诱导期的平稳型动力学曲线;膜厚1.5μm的复合催化剂的活性接近于实验所用的以硅胶为载体的TiCl3催化剂,且其具有相似的衰减型动力学曲线.研究同时表明,不同的膜厚能够调节复合催化剂的氢调性能及所得聚乙烯的分子量分布.     

壳聚糖富氧膜的研究（Ⅱ）

壳聚糖-聚砜酰胺复合膜在干、湿情况下,其富氧性能存在明显的差别,表明壳聚糖是较好的富氧材料。从壳聚糖的结构可看出,它能通过氨基、羟基与许多重金属离子形成螯合物,这种螯合物与低分子氧载体的结构相似.本文在壳聚糖-聚砜酰胺复合膜上固定金属钴盐,并在干、湿两种状态下测定了其富氧性能的差别。     

木质素磺酸钠改性聚砜膜的制备及其在正渗透膜中的应用

采用木质素磺酸钠作为亲水添加剂,通过浸没沉淀相转化法制备了木质素磺酸钠共混改性聚砜膜,以改善聚砜膜的亲水性,并用作正渗透膜的支撑层,以降低内浓差极化效应.利用扫描电子显微镜、衰减全反射傅里叶变换红外光谱仪、水接触角仪等研究了不同木质素磺酸钠添加量对聚砜膜的结构和表面性质的影响.结果表明,添加木质素磺酸钠后,聚砜膜的指状孔变得规整且狭长.水接触角实验证实添加木质素磺酸钠能改善聚砜膜的亲水性,当木质素磺酸钠含量为0.4 wt%时,聚砜膜的表面水接触角可降低至65°.正/反渗透测试装置分别用于表征正渗透膜的传质性质和结构参数.结果表明,以0.4 wt%木质素磺酸钠改性聚砜膜为支撑层的正渗透膜的水渗透性能(A=3.12×10~(-5) LMH×Pa~(-1))优于纯聚砜基底正渗透膜(0.76×10~(-5)LMH×Pa~(-1)),而且前者的结构参数(S=2010mm)远小于后者(3450mm),说明木质素磺酸钠改性聚砜膜有效弱化了正渗透膜的内浓差极化效应.     

侧链磺化型聚砜质子交换膜的设计与制备及其性能研究

在制备氯甲基化聚砜(CMPSF)的基础上,以对羟基苯磺酸钠(HBSS)和羟基苯二磺酸钠(HBDSS)为亲核试剂,通过亲核取代反应,在聚砜(PSF)主链上分别键联了以苯磺酸根(BSS)和苯二磺酸根(BDSS)基团为末端基的侧链,制得了亲水磺酸根基团与疏水主链"微相分离"结构的2种侧链型磺化聚砜PSF-BSS和PSF-BDSS,并优化了制备条件.在对磺化聚砜产物进行充分表征(FTIR和1H-NMR谱)的基础上,采用流延成膜法制备了质子交换膜,测定了质子交换膜的基本性能,重点考察了质子交换膜"芳香性"主链和亲疏水微区"相分离"这2种结构因素对交换膜性能的影响.实验结果表明,在极性较强的溶剂中,CMPSF与羟基苯磺酸钠可顺利地发生亲核取代反应,于100℃经40 h反应可制得磺酸根键合量分别为2.07 mmol/g和2.11 mmol/g的磺化聚砜PSF-BSS和PSF-BDSS.所制备的质子交换薄膜具有较高的质子传导率(PSF-BDSS交换膜室温为4.7×10-2S/cm,80℃为8.1×10-2S/cm),优良的尺寸稳定性(室温溶胀率为8.6%,80℃溶胀率为30%),且具有良好的热稳定性与抗氧化稳定性.     

聚砜阴离子交换膜的制备及结构与性能研究

以1,4-二氯甲氧基丁烷(BCMB)为氯甲基化试剂,使聚砜(PSF)发生氯甲基化反应,制得了氯甲基化聚砜(CMPSF),考察了主要因素对聚砜氯甲基化反应的影响,并使用FTIR及1H-NMR等法对CMPSF的化学结构进行了表征.采用三乙胺(TEA)、三丙胺(TPA)及三丁胺(TBA)等3种叔胺对CMPSF进行了季铵化反应,并以4,4′-联吡啶为交联剂实施了交联反应,制备了聚砜阴离子交换膜(PSFAEM).测定了交换膜PSFAEM的主要性能,包括离子交换容量(IEC)、含水量(WC)及膜电阻(Rm).实验结果表明,使用BCMB,聚砜的氯甲基化反应可顺利进行,以氯仿为溶剂,以SnCl4为Lewis酸催化剂,可制得氯甲基化程度为1.75mmol/g的CMPSF.交换膜PSFAEM的IEC、WC及Rm与季铵化反应时间及叔胺的种类密切相关.季铵化反应时间相同时,采用烷基中碳原子数少的叔胺TEA所制备的交换膜具有高的IEC与WC,低的Rm;使用同一种叔胺时,随季铵化反应时间的增长,交换膜的IEC与WC增大,Rm减小.     

万古霉素手性膜拆分D,L-苯甘氨酸及手性拆分机理

以万古霉素和1,6-己二异腈酸酯为单体,通过界面聚合法在聚砜基膜上制备了万古霉素手性高分子膜.利用红外光谱及扫描电子显微镜对该膜进行了表征.将其用于青霉素及头孢菌素类药物的重要中间体苯甘氨酸的手性拆分,通过优化单体摩尔比、界面聚合时间及外消旋体溶液浓度等分离参数,可达到超过70%的D-苯甘氨酸对映体过剩值的手性分离.通过比较研究手性膜吸附、固相萃取、膜色谱、膜渗析和膜超滤过程,发现手性膜上优先吸附的对映体L-苯甘氨酸并不是各种模式下优先透过的对映体,结合外消旋体的缔合特性,提出了"吸附-缔合-扩散"的手性膜分离机理.     

在聚砜膜表面接枝聚甲基丙烯酸及接枝膜对生物碱化合物的吸附特性

首先将聚砜(PSF)氯甲基化,制得氯甲基化聚砜(CMPSF),CMPSF流延成膜后与乙二胺(EDA)反应,制得表面键合有EDA的氨基化膜(AMPSF)。在此基础上,在水溶液体系中构建氨基-过硫酸盐表面引发体系,使甲基丙烯酸(MAA)发生接枝聚合,制得了功能接枝膜PSF-gPMAA。考察了影响膜接枝过程的主要因素,优化了接枝聚合条件。采用傅里叶红外光谱(FTIR)、光学显微镜(OM)及称重法对接枝膜PSF-g-PMAA进行了表征。最后研究了功能接枝膜对氧化苦参碱和金雀花碱两种生物碱化合物的吸附特性。结果表明,采用氨基-过硫酸盐表面引发体系,可以顺利地实施MAA在PSF膜表面的接枝聚合,接枝度随氨基化膜AMPSF表面氨基键合量的增大而增大,接枝聚合适宜的温度为50℃,溶液中适宜的过硫酸盐用量为单体质量的1.0%。在适宜的条件下可制得PMAA接枝度为4.62mg/cm2的接枝膜。凭借强静电相互作用和氢键作用的协同作用,功能接枝膜PSF-g-PMAA对生物碱化合物可产生强烈的吸附作用,在中性溶液中,对氧化苦参碱和金雀花碱的吸附容量分别可达277μg/cm2和331μg/cm2。     

1-正辛基-3-甲基咪唑六氟磷酸盐离子液体对聚砜分离膜的结构控制及其作用机理

以1-正辛基-3-甲基咪唑六氟磷酸盐[C8mim][PF6]作为膜结构控制剂,采用相转化法制备具有不同孔结构的聚砜分离膜.随着[C8mim][PF6]含量的增大,聚砜膜的孔结构从典型的不对称指状孔结构、高度拉长的大孔结构、典型的大空穴,变化至海绵状孔结构,离子液体[C8mim][PF6]在聚砜膜制备中表现出孔结构控制、增塑作用.通过能谱分析表明,[C8mim][PF6]在所制备的聚砜膜中存在部分的保留,通过水与聚砜膜表面接触角的测定,[C8mim][PF6]在聚砜膜中的残留提高了膜的亲水性能.基于相分离过程的基本理论,探讨了疏水性[C8mim][PF6]在铸膜液相分离过程中孔结构形成的作用机理.研究表明,[C8mim][PF6]在铸膜液中含量越高,对于相分离的延时效应越大,体系更易发生延时分相.     

乙基纤维素三甲硅基衍生物膜的结构表征与氧氮渗透行为

气体分离膜是近年发展起来的应用前途广阔的一个领域。近年来由于非对称膜技术的开发,美国和日本已开始用硅橡胶涂复在多孔聚砜上制成PDMS-PS复合膜。PDMS是透气量最高而稳定的膜材料,但氧氮分离系数仅为2。 乙基纤维素(EC)具有机械强度高、抗热、耐寒和稳定性好等优点,是一种具有潜力的优秀膜材料。其中取代基的位置和含量对膜的性能有较大的影响。日、美等国科学家利用EC对氧氮的良好分离系数制成了中孔纤维材料富氧器、EC涂复在聚二甲基硅氧     

The influence of polypropylene degradation on the membrane wettability during membrane distillation

In the membrane distillation process only gaseous phase can exist in the membrane pores. The resistance to wettability of capillary polypropylene membranes has been investigated in this work. The SEM-EDS investigations revealed that the pores located up to 100 μm from the membrane surface were filled by the feed during the production of demineralized water over a period of 4500 h. However, the pores located inside the membrane wall were still dry and no feed leakage was observed. Both scaling and polypropylene degradation were indicated as the major reason for partial membrane wettability. The SEM-EDS, XRD and FTIR methods were used for investigations of polypropylene degradation, and material cracking and the presence of hydroxyl and carbonyl groups on the membrane surface has been identified. The membranes irradiated by UV light or stored up to 9 years in air were used to evaluate the membrane wetting caused by the products of polymer oxidation. The membrane samples were soaked in either water or a concentrated solution of NaCl at temperature of 343 K, and their wettability was evaluated on the basis of their variations in the air permeability. It was found that the products of polypropylene oxidation significantly accelerated the degree of wettability during the first 30 days of investigations, but after 60 days the results were similar. The soaked membrane samples wetted faster in NaCl solutions than those soaked in distilled water, which came as a result of the chemical reactions of salt with the hydroxyl and carbonyl groups found on the polypropylene surface.     

Theoretical analysis of the performance of composite membrane consisting of the catalytic and nanofiltration layers

A model of the composite membrane consisting of the catalytic layer (CL) and the nanofiltration layer (NFL) is presented. It has been found that applying NFL on the permeate side of CL it is possible to enhance substantially the conversion of substrate into the product. The best performance is obtained for high retention of substrate and low of product. At higher values of volume flow and/or longer catalytic path the retention degree of product becomes negligible. The presence of NFL enhances the influence of distribution of the reaction rate constant, k, on the conversion ratio. Comparing to k = constant the positive effect is obtained if k increases along the catalytic pore, whereas negative—if k decreases.     

Span80-TBP-NaOH体系破乳方法及膜内反应研究

采用Span80-TBP-NaOH体系乳状液膜法提取红土矿浸出液中的镍,对提取分离后的乳液进行破乳实验,经过加热-离心联合破乳法,破乳率可达90%.通过比较提取镍前后,乳液的红外光谱图,证明了膜内反应的发生;通过比较原始油相和破乳后油相的红外光谱图,证明了破乳后油相的重复利用性.     

Effect of compatibility on the structure of the microporous membrane prepared by selective dissolution of chitosan/synthetic polymer blend membrane

The method to prepare microporous chitosan membrane by selective dissolution of its blend was evaluated. Two synthetic polymers, e.g. polyvinyl pyrrolidone (PVP) and polyethylene glycol (PEG), were chosen to be the counterpart polymers. Results of Fourier transform infrared (FTIR) characterization, differential scanning calorimeter (DSC) analysis, wide angle X-ray diffraction (WAXD) measurements showed that there are special interactions between chitosan and the counterpart polymers. The pore structure induced by this method is controlled by the compatibility of the chitosan and the counterpart polymers. No pore structure was induced in the case of chitosan/polyvinyl pyrrolidone because of their molecule level miscibility and strong interaction. Highly porous structure was induced in the case of chitosan/polyethylene glycol because of their poor compatibility and multiphase structure.     

壳聚糖－戊二醛的量子化学从头算

采用量子化学从头算方法研究了壳聚糖-戊二醛交联膜的稳定结构,研究了壳聚糖和戊二醛通过氨醛缩合形成阳离子膜的几何构型、键能、键序和电子迁移,讨论了膜的成键形式和稳定性．     

壳聚糖—戊二醛的量子化学从头算

采用量子化学从头算方法研究了壳聚糖－戊二醛交联膜的稳定结构,研究了壳聚糖和戊二醛通过氨醛缩合形成阳离子膜的几何构型、键能、键序和电子迁移,讨论了膜的成键形式和稳定性。     

Energy-transducing membrane

The states of chlorophyll a (Chl a) incorporated in a liquid crystal membrane were investigated by spectrophotometry in the visible and IR regions.N-(p-methoxybenzylidene)-p′-butylaniline (MBBA) was used as the liquid crystal. The Chl a-MBBA (1∶3 in molar ratio) showed the dihydrate-Chl a aggregate peak at 743 nm under excess water conditions. IR spectroscopic evidence indicated that the Chl a-MBBA membrane was hydrated in the dihydrate stoichiometry [Chl a-3MBBA-2H₂O], via the C-10 ester OC…H(H)O…Mg and the C-9 keto OC…H(H)O…Mg bondings.     

膜生物反应器中AHL分析技术研究进展

膜生物污染一直是膜生物反应器(membrane bioreactor,MBR)在废水处理工艺中需要解决的一大难题。最近研究表明：基于群体感应的淬灭技术可以作为MBR活性污泥体系中一种有效的膜生物污染防治策略。因而,识别和分析群体感应产生的信号分子是应用群体淬灭技术防治MBR中膜生物污染的关键。本文首先介绍了活性污泥体系中的群体感应机理和N-酰基高丝氨酸内脂(N-acyl homoserine lactone,AHL);其次,归纳近期研究中针对MBR中AHL定性和定量分析方法;最后,对MBR中AHL识别及分析技术应用进行了展望。     

Synthesis of polypiperazine-amide thin-film membrane on PPESK hollow fiber UF membrane

A new interfacial polymerization (IP) procedure is developed in order to synthesize polypiperazine-amide thin-film membrane on the inner surface of poly(phthalazinone ether sulfone ketone) (PPESK) hollow fiber ultrafiltration (UF) membrane.A hollow fiber composite membrane with good performance was prepared and studied by FT-IR and scanning electron microscopy.     

Transport of acetylcholine in a membrane

A laminate model of the cleft-plus-postsynaptic membrane structure of the neuromuscular junction was studied. In order to prepare a model of the postsynaptic membrane, the properties of acetylcholine (Ach) receptor-rich vesicles purified from Torpedo fish were measured. Immobilization of vesicles was demonstrated by various methods, in particular, by investigating collagen and carrageenan matrices as models of the fluidfilled fibrous matrix of the cleft. It was found that a laminated system employing a liquid membrane-containing vesicle suspension, together with a swollen collagen membrane, is an appropriate model for examining important transport/reception aspects of the cleft-plus-postsynaptic membrane structure. Combined transport with immobilization of Ach in the liquid membrane system was elucidated and effective diffusivities in the vesicle suspension layer were calculated. Effective diffusivities of the composite system simulating the cleft and the postsynaptic membrane were evaluated as well. These data illustrate the importance of penetrant immobilization in retarding the diffusion process during neurotransmission.