动态Monte Carlo模拟蛋白质与微滤膜相互作用及其对微滤过程影响

构建了二维晶格蛋白质-微滤膜疏水相互作用模型，采用动态Monte Carlo方法模拟了微滤膜污染过程及其受膜孔径、蛋白质浓度和蛋白质结构特性等因素的影响。模拟结果显示：微滤过程中膜通量的变化呈现快速下降、缓慢下降和平台期3个阶段。小孔径微滤膜的滤阻从以膜孔阻力为主转变为以饼层阻力为主;而大孔径微滤膜的滤阻则以膜孔阻力为主。提高蛋白质浓度会强化滤阻从膜孔阻力向饼层阻力的转变。在微滤过程中，蛋白质会因疏水相互作用在膜孔内发生构象转换，进而发生不可逆吸附并形成多层堆积，导致膜污染和通量下降，提高蛋白质的构象稳定性可以显著降低其对微滤膜的污染。分子模拟结果与文献报道的实验结果和理论模型相符，所提供的微观信息对于微滤过程优化和微滤膜设计具有参考作用。     

颗粒粒径和膜孔径对陶瓷膜微滤微米级颗粒悬浮液的影响

通过测定颗粒悬浮液通过陶瓷微滤膜时的参透通量及污染阻力,确定了陶瓷膜处理微米级颗粒悬浮液时,颗粒粒径和膜孔径对微滤过程的影响和膜污染机理,获得了微米级颗粒悬浮液微滤过程中膜孔径的选择方法。     

苦楝素酶解法提取液微滤过程的研究

采用微滤膜法对苦楝素酶解法提取液进行分离.优选出PES微滤膜,研究了膜孔径、操作压力、操作温度对微滤性能的影响.结果表明,在微滤膜孔径0.22 μm,操作压力0.12 MPa,操作温度25 ℃条件下,微滤平均渗透速率为49.1 mL/h,苦楝素透过率为73.97%.     

平板α-Al2O3陶瓷微滤膜的制备与表征

采用固态粒子烧结法和浸拉提渍工艺研制出α-Al2O3平板式陶瓷微滤膜,探讨涂膜液中固含量对膜孔径及纯水通量的影响,并研究涂层工艺及烧成制度对膜形成的作用。同时对微滤膜的孔径大小及分布,膜孔隙率、纯水通量及抗弯强度等性能进行表征。实验结果表明,制备出平均孔径为0.7μm的平板陶瓷膜,其具有表面性质连续完整、孔径分布窄以及机械强度大的特点。     

氧化铝微滤膜的制备及表征

通过固相粒子烧结法分别制备了膜孔径为0.1,0.4,0.8,1,3μm的氧化铝微滤膜.氧化铝微滤膜膜厚与涂膜液中氧化铝的含量成正比.采用SEM,干湿膜法孔径测定仪及过滤等方法对膜进行了表征,过滤法作为测定氧化铝膜完整性的方法之一,对测定工业生产的氧化铝微滤膜的完整性具有现实意义.     

湿式催化氧化/膜过滤组合工艺膜过滤机理

采用湿式催化氧化/膜过滤组合工艺,以Mo-Zn-Al-O粉末作为催化剂降解阳离子红GTL模拟染料废水,探讨在膜过滤过程中平均孔径为0.1 μm的微滤和0.022 μm的超滤聚偏氟乙烯(PVDF)中空纤维膜的过滤机理。实验结果表明,两种膜过滤组合工艺对染料的降解效果均优于单独湿式催化氧化,0.01 MPa恒压条件下运行120 min后微滤和超滤的膜通量分别衰减了26.63%和16.48%,其原因是粉末催化剂可在微滤膜孔内部沉积形成中间阻塞过滤,后在表面形成滤饼层;而在超滤膜表面仅形成滤饼层。通过实验结果对膜阻力进行计算,可知在相同反应过程后微滤膜产生的不可逆阻力大于超滤膜。在不同反应条件下,催化剂的沉积量与膜阻力呈现线性相关。     

微滤膜材料分析研究

以聚偏氟乙烯（PVDF）微滤膜为研究对象,采用了多种分析手段,对其材料组成和结构进行了分析,研究结果表明：该微滤膜为疏水性膜,其接触角为121°;微滤膜表层材料主要为聚偏氟乙烯,未进行化学改性,共混有无机物二氧化硅;其支撑层的材料为高密度聚乙烯（HDPE）;微滤膜孔径分布均匀,表层的孔呈指孔状结构,截面孔分布呈海绵状分布,为不对称膜。     

二硫化钼生产废水的特征及资源化利用

采用"颗粒富集—电石渣中和—离子交换"工艺处理二硫化钼化学提纯产生的废水,考察了微滤膜孔径、水乳比因素对二硫化钼回收率和出水pH值的影响。实验结果表明:微滤膜孔径越小,二硫化钼回收率越高;水乳比越小,出水pH值越高。在采用微滤膜孔径0.2μm、水乳比8∶1的实验条件下,二硫化钼回收率达到99.76%,出水pH值达到6.95。经离子交换装置处理后的废水达到车间循环用水要求。     

溶液环境对陶瓷膜微滤微米级颗粒悬浮液的影响

本文研究了溶液环境对陶瓷微滤膜处理微米,亚微米级颗粒悬浮液过程的影响,通过测定电解质溶液种类,浓度对微滤过程渗透通量的影响,及溶液环境对微滤过程影响随颗粒粒径,膜孔径的变化,确定了溶液环境对微滤过程的影响主要是由于其引起了颗粒表面Ｚｅｔａ电位的变化,改变了颗粒在溶液中的分散情况,并引起了决定膜通量的颗粒粒径／膜孔径比值的变化,从而改变了微滤过程。     

铸膜液结构对PVC/PMMA合金微滤膜性能的影响

通过高分子合金化,以L-S相转化法制备了PVC/PMMA非对称型合金微滤膜,考察了铸膜液结构对微滤膜结构与性能的影响.结果表明:随聚合物浓度、铸膜液温度升高合金膜水通量降低,平均孔径减小;增大PMMA含量,水通量上升,平均孔径增大;随添加剂量的增加,合金膜水通量上升,平均孔径减小.     

Sieve mechanism of microfiltration separation

A theoretical model of dead-end microfiltration purification (MFP) of dilute suspensions is suggested. The model is based on a sieve mechanism of MFP and takes into account the probability of membrane pore blocking during MFP of dilute colloidal suspensions. An integro-differential equation (IDE) that includes both the membrane pore size and particle size distribution functions is deduced. According to the suggested model a similarity property is deduced, which allows one to predict the flux through the membrane as a function of time for any pressure and dilute concentration based on one experiment at a single pressure and concentration. For a narrow pore size distribution in which one pore diameter predominates (track-etched membranes), the IDE is solved analytically and the derived equation is in a good agreement with the measurements on four different track-etched membranes. A simple approximate solution of the IDE is deduced and that approximate solution as well as the similarity property of MFP process is in a good agreement with the measurements on a commercial Teflon microfiltration membranes.     

膜技术在荷叶黄酮分离纯化中应用

运用膜技术对荷叶黄酮提取液进行纯化.实验分别采用微滤膜和超滤膜对荷叶黄酮提取液进行初步纯化,研究表明孔径为50 nm的微滤膜Ⅱ对荷叶黄酮提取液有较好的除杂效果,黄酮透过率为97.4％,平均通量为186.7 L×h-1×m-2,且运行稳定;采用纳滤膜和反渗透膜对微滤膜的滤液进行浓缩,研究表明,纳滤膜在浓缩过程中能去除部分盐分等小分子物质,进一步纯化了黄酮溶液,纳滤膜平均通量为32.8L×h-1×m-2,透过率0％.     

氧化钛-氧化铝复合微滤膜的制备

采用悬浮粒子烧结法制备氧化钛 -氧化铝复合微滤膜 ,研究了膜厚度、烧结时间和烧结温度对膜的孔径及其分布的影响。     

TiO2对微滤陶瓷复合膜改性的研究--反应物种类的影响

分别以硫酸钛，硫酸氧钛作为起始反应物，采用均相沉淀法对微滤陶瓷复合膜进行了TiO2的涂覆改性研究。实验结果表明；采用硫酸钛制备的TiO2改性膜致密光滑，晶粒尺寸在20nm以下，使改性后的微滤膜水通量提高了19.2%;而采用硫酸氧钛制备的TiO2改性膜表面粗糙，晶粒尺寸超过40nm，反而使改性后的微滤膜水通量降低了56.9%。     

面向过程的陶瓷膜材料设计理论与方法(Ⅱ)颗粒体系微滤过程中膜结构参数影响预测

以所建立的颗粒体系微滤过程中膜结构参数与渗透性能关系模型为基础,在膜孔径和颗粒粒径均为正态分布的理想条件下对膜孔径、膜厚度、孔隙率对膜稳态通量的影响进行模拟计算.结果表明：对于颗粒悬浮体系的分离存在最优膜孔径使膜通量最大,该最优孔径随颗粒平均粒径增大、颗粒粒径分布变窄而有所增大.模拟计算结果有助于深入理解膜微观结构对宏观性能的影响.     

炭膜处理印染废水的影响因素

用不同孔径的酚醛树脂基管状微滤炭膜,对两种模拟染料废水溶液进行处理,考察了膜孔径、原料液浓度、测试压力和测试时间对截留率和膜通量的影响。实验结果表明,微滤炭膜对模拟染料废水有较好的处理效果,截留率和膜通量受膜孔径及操作条件的影响。     

The effect of surface polarity and pore dimension on the adsorption of polar molecules on activated carbon cloth

The adsorption of cyanogen chloride (CK) on carbon cloth activated to various degrees was studied. At intermediate activation time, maximum adsorbent-adsorbate interaction is manifested corresponding to a fit of the pore size to the dimension of the adsorbate molecule. Comparison of the maximum interaction effect of this highly polar molecule with that of nonpolar molecules and with water shows that, unlike the polar and hydrogen-bonding water molecule, only minute clustering occurs with CK at the pore size that corresponds to maximum interaction. Carbons enriched with surface oxygen groups bring about slightly smaller pore size of maximum interaction (PSMI), compared to oxygen-depleted carbon. The effect is attributed to greater dipoledipole interaction with the polar surface. The possibilities of optimizing adsorption isotherms and estimating the average ultramicropore size by utilizing the maximum interaction effect are discussed.It is stated that the pore size of maximum interaction provides an estimate of the average pore size of the molecular sieve carbon, which, quite probably, cannot be obtained otherwise, and the molecular sieving effect discussed in previous papers may serve to assess the pore constriction or aperture dimensions of the molecular sieve.     

Micro‐ and ultrafiltration film membranes from poly(ether ether ketone) (PEEK)

Film membranes from the thermoplastic poly(ether ether ketone) (PEEK) have been extruded and tested for their microfiltration and ultrafiltration performance. High‐performance asymmetric membranes have been obtained by extruding polymer blends of PEEK, polysulphone, and a small molecule solvent mixture, and then by removing the polysulphone and solvent in a subsequent extraction step. The process for making ultrafiltration membranes differs from microfiltration membranes only in the relative blend components, and the temperature of the film pick‐up rolls. Processing parameters with important effects on the membrane performance have been identified. Microfiltration membranes are characterized by their pore‐size distributions and SEM, and ultrafiltration membranes by their rejection of bovine serum albumin, bubble point, and SEM. Composite membrane for nanofiltration utilizing the PEEK ultrafiltration membrane as a substrate performed similarly to a commercial membrane for the same purpose. This work details the best method for making PEEK film membranes published to date. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 1146–1155, 1999     

Effect of chemical vapor deposition of toluene on gas separation performance of carbon molecular sieve membranes

Journal of Porous Materials - A carbon molecular sieve (CMS) membrane is a microporous membrane that can serve as a molecular sieve. Tuning the pore size of a CMS membrane to improve the...