聚偏氟乙烯中空纤维膜的研制和应用

介绍了聚偏氟乙烯(PVDF)中空纤维膜的制备工艺，讨论了PVDF含量、添加剂、纺丝温度、干程及卷绕速度对膜性能的影响．并就PVDF中空纤维膜3种应用方法——连续膜过滤、膜生物反应器、双向流过滤的技术原理及应用作了介绍．     

涂层法制备聚醚砜中空纤维纳滤膜及应用

以磺化聚醚醚酮(SPEEK)为内涂层制备了聚醚砜中空纤维纳滤膜,研究了溶剂、SPEEK磺化度、浓度及后处理温度等参数对膜性能的影响.结果表明,以SPEEK(磺化度0.55)的1%甲醇溶液为涂层溶液,经过30℃后处理6h制得纳滤膜具有较高的通量和离子选择性.其应用于含盐染料废水分离.结果显示,该膜完全截留小分子染料,但是透过单价盐类.该膜为单价/多价盐离子的分离和含盐染料废水的处理提供了一种新的可能性.     

纳米TiO2改性PVDF中空纤维膜的制备及性能研究

疏水性聚偏氟乙烯(PVDF)膜的亲水化改性是当前膜分离技术研究的热点之一。利用共混改性将纳米TiO2颗粒加入铸膜液,通过溶胶凝胶法制备改性PVDF中空纤维膜。采用AFM和SEM对膜表面进行表征,以接触角,孔隙率,水通量和平均孔径为评价标准,确定改性膜中纳米TiO2颗粒投加的最佳比例。结果表明:与未改性膜相比,改性膜表面平滑,粗糙度明显降低;改性膜断面的孔状结构更加微小,内部主要以海绵状为主;改性膜的接触角及孔隙率均有所改变,膜表面的亲水性增强,纯水通量提高4-5倍,最大达657.3L/m2.h。     

Liquid-phase microextraction combined with hollow fiber as a sample preparation technique prior to gas chromatography/mass spectrometry

Two modes of liquid-phase microextraction (LPME) combined with hollow fiber (HF) were developed for gas chromatography/mass spectrometry (GC/MS). Both methodologies, that is, static LPME with HF and dynamic LPME with HF, involved the use of a small volume of organic solvent impregnated in the hollow fiber, which was held by the needle of a conventional GC syringe. In static LPME/HF, the hollow fiber impregnated with solvent was immersed in the aqueous sample, and the extraction processed under stirring; in dynamic LPME/HF, the solvent was repeatedly withdrawn into and discharged from the hollow fiber by a syringe pump. This is believed to be the first reported instance of a semiautomated liquid microextraction procedure. The performance of the two techniques was demonstrated in the analysis of two PAH compounds in an aqueous sample. Static LPME/HF provided approximately 35-fold enrichment in 10 min and good reproducibility (approximately 4%). Dynamic LPME/HF could provide higher enrichment (approximately 75-fold) in 10 min and even better reproducibility (approximately 3%). Both methods allow the direct transfer of extracted analytes to a GC/MS system for analysis.     

电化学法聚吡咯空心微球的制备及表征

以水为溶剂,对甲苯磺酸和十二烷基苯磺酸钠为支持电解质,采用电化学方法制备了聚吡咯(PPy)空心微球。运用扫描电镜(SEM)对产物的微观形貌进行了表征,发现十二烷基苯磺酸钠的用量对产物的形貌有很大的影响。运用傅立叶红外光谱(FTIR)对产物的结构进行了表征,结果表明,对甲苯磺酸根和十二烷基苯磺酸根离子已经掺杂到聚吡咯分子链上。对聚吡咯进行了交流阻抗谱(EIS)的研究,结果表明聚合电压和聚合时间对EIS曲线有很大的影响。     

聚四氟乙烯中空纤维膜的制备

通过聚四氟乙烯(PTFE)树脂糊料挤出和拉伸烧结成型方法,制备PTFE中空纤维膜.考察了拉伸倍数、温度和速度等拉伸工艺和烧结工艺对PTFE中空纤维膜的结构和性能的影响.实验结果表明,制膜参数中,随着拉伸倍数和温度的增加,平均孔径和孔隙率增加,泡点降低;随拉伸速度增大,膜平均孔径变小,泡点增加,拉伸速度对孔隙率的影响则呈现无规律变化;烧结可提高PTFE中空纤维膜的强度,孔径和孔隙率增加.PTFE中空纤维膜具有明显的非对称结构.     

复合增强聚偏氟乙烯中空纤维膜的制备研究

提出了一种新的中空纤维膜增强方法.采用非溶剂致相分离法,将聚偏氟乙烯铸膜液和作为基膜的高固含量聚偏氟乙烯铸膜液,与芯液一起,通过特殊结构的纺丝喷头同时挤出,制备复合增强的聚偏氟乙烯中空纤维膜.期望复合膜保持原有孔径和高通量,同时具有更高的断裂强力.研究了复合层配方对膜结构和性能的影响.结果表明,随着复合层聚偏氟乙烯固含量减少,靠近外皮层的指状孔结构向大空穴结构转化,外表面开孔数和孔径增加,纯水通量增大,断裂强力有所减小.     

PVDF／TPU相容性分析及中空纤维膜的制备与表征

通过DSC扫描分析PVDF/TPU共混后二者相容性.采用相转化法制备PVDF/TPU中空纤维膜.牛血清白蛋白截留实验、FTIR-ATR红外光谱扫描、扫描电子显微镜分析共混时添加水溶性聚合物聚乙烯吡咯烷酮(PVP)后对中空纤维膜分离性能、微观结构、晶相组成的影响.结果表明,PVDF/TPU为部分相容体系,添加适量的PVP伊可以明显改善PVDF的亲水性和膜过滤性能.     

Titanate nanotubes: preparation, characterization, and application in the detection of dopamine

Titanate nanotubes were successfully synthesized via a hydrothermal process with the assistance of surfactant. These nanotubes with average length of several hundred nanometers and diameter of 10 nm were employed to modify glass carbon electrode and measure dopamine via electrochemistry method. The experiments showed ideal reversibility in cyclic voltammetry, which might be due to the decrease of the overvoltage of the electrode and increase of electron transference. The results illustrated the potential application in the detection of dopamine.     

红外空芯光纤辐射温度计的研制及应用

为了对冲击发电机的轴套温度进行监测,设计并研制了一种新型的红外光纤辐射温度计.温度计主要由红外空芯玻璃光纤、红外探测器、放大电路及80C552单片机组成.在分析各部分实现功能的基础上,重点研究了环境温度变化对探测器的影响,并实现了数学建模.温度计的工作波长是8~14μm,测量温度范围是60~400℃,测试环境温度范围是25~60℃.利用可精确控温的实物标定炉和环境模拟箱对温度计进行了标定,测量误差小于2%.经过几个月的在线监测,取得了较好的测量结果.     

中空纤维分子印迹PVDF超滤膜的制备与表征

基于伪模板技术，通过表面涂覆热聚合的方法制备分子印迹膜。衰减全反射FTIR和扫描电镜表征表明改性后PVDF膜表面形成了印迹聚合物层。印迹膜的改性率约为2．3mg／cm^2，其纯水通量约为9．40L／（m^2·h·Bar）。利用动态过滤实验考察了聚合物膜对水相分子的选择性透过性能，结果表明印迹膜可以选择性地透过模板类似物。在pH=7．6时，印迹膜分离因子α约为1．8，而在pH=10．5时，α在1．2左右，表明疏水作用在水相中有促进识别的作用。     

石墨烯制备、表征及应用研究最新进展

石墨烯由于其特殊的电学、热学、力学等性质以及在纳米电子器件、储能材料、光电材料等方面的潜在应用,引起了科学界新一轮的"碳"热潮。分析了近1年来发表在Science、Nature等期刊上的关于石墨烯的论文,对石墨烯制备、表征及应用方面的最新进展进行了综述,并对各种制备技术及表征手段进行了分析评价。     

Kinetics and the on-site application of standards in a solid-phase microextraction fiber

The kinetics of the desorption of analytes from a SPME fiber into an agitated sample matrix was studied, and a theoretical model was proposed to describe the dynamic desorption process, based on the steady-state diffusion of analytes in the extraction phase and in the boundary layer. It was found that the desorption of analytes from a SPME fiber into an agitated sampling matrix is isotropic to the absorption of the analytes onto the SPME fiber from the sample matrix under the same agitation conditions, and this allows for the calibration of absorption using desorption. The calibration was accomplished by exposing a SPME fiber, preloaded with a standard, to an agitated sample matrix, during which desorption of the standard and absorption of analytes occurred simultaneously. When the standard was the isotopically labeled analogue of the target analyte, the information from the desorption process, i.e., time constant a, could be directly used for estimating the concentration of the target analyte. When the standard varied from the target analyte, the mass-transfer coefficient of the analyte could be extrapolated from that of the standard. These predictions agree well with experimental results. This approach facilitates the full integration of sampling, sample preparation, and sample introduction, especially for on-site or in vivo investigations, where the addition of standards to the sample matrix, or control of the velocity of the sample matrix, is very difficult.     

硅橡胶-聚砜中空纤维复合膜的制备及性能研究

主要讨论硅橡胶 -聚砜中空纤维复合膜的制备工艺 ,并对所制备的膜组件进行透气性能研究 .考察了涂膜液浓度、涂膜压力对膜组件性能的影响 ,发现过高的涂膜压力不利于组件富氧空气通量的提高 .     

聚偏氟乙烯中空纤维微孔膜的应用及清洗方法

采用聚偏氟乙烯中空纤维微孔膜进行了油田采出含油污水净化回注、轧钢厂冷却水净化回注、轧钢厂冷却水净化回用、生活废水活性污泥膜法净化处理等项工作。取得了良好的效果,设计了一种能内外同时进行清洗的中空纤维分离装置气流振荡清洗新工艺。可迅速有铲地将外压式中空纤维膜上附着的污染物去除,恢复膜透过通量。     

相转化法制备中空纤维陶瓷膜的研究进展

利用相转化法制备中空纤维陶瓷膜具有操作简单、成膜微观结构可控、一步成型等优点.因此成为目前最常用的中纤维陶瓷膜的制备方法之一.首先论述了相转化法的过程,成膜机理,其次介绍了相转化法制膜过程中的影响因素,以及在膜烧结过程中烧结温度、保温时间、升温速率和烧结助剂对膜的影响,最后,对中空纤维陶瓷膜未来的研究方向提供了建议.     

银粒子修饰聚醚砜抗污染中空纤维膜的制备与性能研究

采用原位还原法制备的银粒子对聚醚砜中空纤维超滤膜进行修饰以提高膜的抗污染能力。以聚乙烯吡咯烷酮(PVP)为分散剂,乙二醇为还原剂,在聚醚砜溶液中将硝酸银还原成银粒子,同时采用相转化法制备中空纤维超滤膜。与未修饰的聚醚砜膜相比,经过银粒子修饰的聚醚砜中空纤维膜的抗污染能力和力学性能都得到明显提高,并且膜的初始水通量和截留率也高于未修饰的膜。当PVP含量为7.5%时,银粒子修饰的聚醚砜中空纤维膜的抗污染能力达到最强,膜的综合性能达到最佳:初始水通量为183L/(m2.h),截留率为94.5%,断裂强度为2.87MPa。在此条件下制备含银膜时,银的流失率仅为4.7%,每100g膜中银粒子的含量为4.55g。     

Fabrication, characterization, and potential application of carbon fiber cone nanometer-size electrodes

A novel method has been developed for the fabrication of carbon fiber cone nanometer-size ultramicroelectrodes (nanoelectrodes) with overall tip dimensions as small as 50 nm in diameter. In this method, carbon fibers were initially etched by an argon ion beam thinner. Afterward, a single etched carbon fiber was inserted into a glass capillary, which was then sealed by heating the glass/fiber interface in a vacuum; thus, no epoxy resin is involved. The success rate of our fabrication route for the electrodes with overall tip diameters of up to 500 nm was about 80%; for those with tip diameters of up to 100 nm, it was about 50%. The fabricated carbon fiber cone nanoelectrodes (CFCNEs) were inspected by optical and scanning electron microscopy. Their electrochemical behavior was examined by cyclic and linear sweep voltammetric measurements of ferricyanide and ferrocene ions in aqueous and nonaqueous media. The potential analytical applicability of the CFCNEs was tested by differential pulse voltammetric measurements of two well-known neurotransmitters, dopamine (DA) and 5-hydroxytryptamine (5-HT), and the results achieved were highly satisfactory. The calibration plots obtained were linear over the ranges from 5.0 × 10(-7) to 1.0 × 10(-4) and from 2.0 × 10(-6) to 1.0 × 10(-4) mol/L, with limits of detection of 1.0 × 10(-7) and 5.0 × 10(-7) mol/L for DA and 5-HT, respectively. Some advantages and improvements of the proposed CFCNE fabrication method, especially with respect to smoothness of the fiber (electrode) surface, strength, and control over the fiber tip dimensions, are also discussed.     

单皮层中空纤维超滤膜及其应用

简要介绍了单皮层中空纤维超滤膜制备的思路、原理和工艺方法，并对其在各个领域中的应用进行了讨论．