超滤技术去除羟基喜树碱中细菌内毒素的研究

考察了超滤技术去除羟基喜树碱原料药中细菌内毒素的效果。采用10 kDa截留分子量超滤膜对羟基喜树碱原料药溶解液进行超滤,以动态浊度法定量检测超滤前后羟基喜树碱中细菌内毒素的含量。结果表明:样液超滤前细菌内毒8.103 5 EU/mL,超滤后为0.307 6 EU/mL,内毒素去除率为96.20%,其有效成分羟基喜树碱的透过率为96.1%。超滤技术可以很好的去除羟基喜树碱原料药溶解液中细菌内毒素,有效成分损失极其微少,可提高其用药安全性。     

超滤对清开灵注射液含量成分的影响

通过用5KD和10KD分子量超滤膜对清开灵注射液的精制终端＂八混液＂进行超滤,分析2个级别超滤膜对产品含量成分等影响。实验结果显示：10KD分子量终端超滤可用于清开灵注射液终端超滤,有益于产品质量提高;用5KD分子量对清开灵注射液进行终端超滤,损失含量较大,色泽浅,有关检验项目指标难以控制在标准范围内,有待于进一步实验研究。     

浸没式超滤海水预处理工艺

目前渤海湾反渗透海水淡化工程多采用新型的超滤膜法预处理工艺,为提高预处理效果,主要进行超滤膜材料和性能改进以及膜组件运行参数的优化,而对超滤膜前预处理的研究相对较少。本实验研究了超滤与混凝/超滤作为反渗透海水淡化预处理工艺的处理效果。考察了两种预处理工艺条件下浸没式超滤膜比通量(SF)、进水水质、产水水质,膜孔孔径变化、反洗效果及膜表面污染情况。结果表明,超滤与混凝/超滤两种预处理工艺都能达到产水SDI₁₅<2.0;混凝处理可以大幅度降低海水中颗粒数目,降低颗粒物在膜表面沉积和吸附的概率,减轻超滤膜的污染。当采用混凝/超滤工艺时超滤膜表面滤饼层疏松多孔,膜孔孔径变化较小,超滤膜比通量的衰减速度减缓,反洗时超滤膜比通量恢复率较高。     

超滤法浓缩棉籽溶解蛋白的数学模型

通过测定纯水的膜通量得到了超滤膜的膜阻力,考察了操作压力、蛋白质溶液浓度对膜通量的影响,建立了超滤的数学模型,该模型的预测值与实验值之间的平均偏差4.1%,最大偏差14.1%。根据所建立的模型,通过计算获得了超滤膜两侧的渗透压。     

超滤一体化装置处理闽江高含藻原水的效果

考察了集混凝—斜管沉淀—超滤于一体的装置在高藻水期对闽江水的净水效果。结果表明超滤一体化装置出水浊度小于0.1 NTU,浊度去除率达到99%以上;出水CODMn均值为1.40 mg/L,出水UV254为0.024 cm-1,CODMn和UV254去除率分别为57.3%和50.1%;出水细菌含量低于《生活饮用水标准》(GB 5749—2006)的限值,细菌去除率大于99%。超滤组合工艺对藻类处理效果优于水厂工艺,藻类总去除率为99.3%。当膜通量下降时,缩短过滤时间、延长反冲洗时间可以使膜通量恢复;当超滤膜出现不可逆污染时,通过CIP清洗恢复膜过滤性能。在高藻水期,水温对膜通量和TMP影响较小,在保证出水水质的前提下,较大的膜通量运行更节能。     

吸附剂预沉积超滤膜过滤腐殖酸影响研究

以自备羟基铁(FeO_xH_y)作为吸附剂,通过吸附剂预沉积超滤的方法,考察吸附磷酸盐前后对超滤膜过滤腐殖酸时的膜通量及膜出水水质的影响。实验结果表明:吸附剂预沉积超滤膜较膜滤,膜比通量升高,水质改善,且存在一个最佳吸附剂投加值0.45 g/L。吸附剂在吸附了一定量磷酸盐后,沉积层致密性变差、粗糙程度变大、膜比通量升高值少,膜出水水质也存在一定程度下降。     

超滤法对清喉颗粒除杂效果的研究

目的：考察超滤技术对清喉颗粒的除杂效果。方法：以绿原酸、总黄酮、牛蒡子苷保留率及固形物减少率为指标,对膜分子量、药液比、温度、加水量等4因素进行考察。结论：确定超滤工艺为：药液比为1∶16（g/ml）的药液,在40℃条件下进行超滤（超滤膜的截留分子量为20万）,在超滤过程中补加5倍量水。采用超滤技术对药液进行除杂,能够有效去除药液中的热原,提高药液澄明度,较大程度保留有效成分。     

膜结构和DOM相对分子质量分布对城市二级出水超滤过程的影响

考察了膜孔径、膜孔隙率以及水中溶解性有机物( DOM)相对分子质量分布对二级出水超滤膜过程的影响.结果表明,膜孔孔径对膜污染特性有一定影响,孔径越大,则膜纯水通量越大,单位时间在膜表面和膜孔内形成污染的有机物也越多,膜污染也越严重,导致通量衰减幅度较大;对于膜孔径相近的膜来说,孔隙率大意味着水通量大,过滤过程对膜产生的...     

超滤去除水溶液中聚乙二醇的研究

采用截留分子量为10kDa和50kDa的超滤膜,对不同分子量的聚乙二醇(PEG)溶液进行了截留实验。考察了超滤对不同分子量PEG的去除效果,膜的截留分子量、操作条件及料液浓度对PEG去除效果的影响,讨论了操作压力和过滤时间对超滤膜过滤通量的影响,分析了超滤(UF)对PEG的去除机理和超滤膜的污染机理。     

不同截留分子量超滤膜包浓缩狂犬病病毒的效果

目的比较不同截留分子量超滤膜包浓缩狂犬病病毒(rabies virus,RV)的效果。方法将RV固定毒3aG-V株按0.01 MOI比例接种至Vero细胞中,制备RV原液,分别用截留分子量100 KD和300 KD的膜包超滤浓缩60倍,β-丙内酯灭活后,验证病毒液浓缩过程膜下液的病毒灭活效果;采用Sepharose 4FF凝胶层析纯化灭活的病毒浓缩液,Lowry法测定病毒浓缩液和纯化液中的蛋白质含量;酶联免疫法测定病毒浓缩过程膜下液、浓缩液和纯化液中的RV抗原含量。结果 100 KD和300 KD的超滤膜包均能有效截流RV,3次试验膜下液RV抗原含量均为0 IU/ml,观察期内小鼠均健存。300 KD膜包超滤的浓缩液和纯化液比100 KD超滤膜包超滤的浓缩液和纯化液中杂蛋白含量低,抗原含量高。结论截留分子量300 KD的膜包比100 KD的膜包更适用于RV的浓缩。     

清开灵注射液药用水牛角中总氮含量的测定及其HPLC指纹图谱的建立

建立了水牛角的质量控制方法,提高了清开灵注射液药用水牛角的内控标准。将水牛角用Ba（OH）2溶液水解后,采用氮测定法和HPLC法对10批水牛角水解液进行总氮和指纹图谱测定。结果表明,总氮测定中,精密度试验RSD为1.30%,重现性试验RSD为1.25%,方法稳定性RSD为1.08%,水牛角水解液中总氮含量均值为76.92 mg/mL,RSD为5.43%,各批间总氮含量有一定差异。HPLC指纹图谱测定通过了方法学考察,建立了标准指纹图谱。10批样品相似度较好。通过建立总氮和指纹图谱的检测方法,提高了水牛角的内控质量标准,为减少清开灵注射液的批件差异打下了基础,同时为其它中药材的质量控制提供了思路。     

混合溶剂对TiO2/PVDF平板超滤膜性能和结构的影响

采用N,N-二甲基乙酰胺(DMAC)和N-甲基吡咯烷酮(NMP)为混合溶剂制备PVDF超滤膜。考察了不同混合比例的DMAC和NMP对膜性能及膜结构的影响,同时利用扫描电子显微镜(SEM)对膜表面及断面结构进行分析,原子力学显微镜(AFM)对膜表面粗糙度进行了分析,利用接触角测量仪对膜表面接触角进行了测量。结果表明,使用混合溶剂对膜孔径和膜亚层结构影响较大,但混合溶剂对膜孔隙率和接触角基本没有影响。当混合溶剂DMAC/NMP为1:2时,膜性能达到最优,孔隙率为70%,平均孔径为0.24μm,水通量为373 L.m-2.h-1,截留率为88%。     

聚氨酯/二氧化硅超滤膜的制备及应用研究

利用溶胶-凝胶法制备了二氧化硅含量及粒径均不同的聚氨酯/二氧化硅超滤膜,并用膜性能测试仪及扫描电子显微镜分别测试膜的性能及其微孔结构形态。实验结果表明聚氨酯复合膜中二氧化硅含量增加,其水通量增加趋势明显;二氧化硅粒径不同时,其在提升膜的水通量方面的作用差别较大;随二氧化硅用量增加,膜的截留率与孔隙率呈先升后降趋势,但不同粒径二氧化硅所起的作用不同,最佳用量也不同。将制得的超滤膜用于处理麻杆蒸煮废液并测定了其对化学耗氧量及色度的去除率。     

Nonuniform deposition of particles inside the pores of a semipermeable membrane

Macroscopic equations of the theory of filtration through granular beds are used to consider the spatial nonuniformity of particle deposition on pore walls during the standard blocking of the pores of ultrafiltration (UF) and microfiltration (MF) membranes. It is shown that the thickness of the layer of particles deposited inside the pore is characterized by a high degree of nonuniformity, which considerably affects the values of membrane permeate flux and selectivity. The effect of pore diameter, pore length, transmembrane pressure, and the coefficient of particle deposition onto the inner pore surface on the performance of standard blocking is studied. A dimensionless number representing the combination of the above parameters is proposed. The number can be used for optimizing the choice of membranes and process parameters for the UF and MF processes using standard blocking.     

Preparation and characterization of polysulfone ultrafiltration membranes for concentrating waste tuna broth

Three sets of ultrafiltration (UF) membranes were prepared containing the following proportions (w/w) of polysulfone and dimethylacetamide: 14.5/85.5, 15.0/85.0 and 15.5/84.5. The membranes were characterized in terms of water flux, molecular weight (MW) cut-off, fouling, average pore size and ratio of pore surface area to membrane area. Membrane water flux was found to decrease as the polysulfone concentration or membrane thickness was increased. Scanning electron microscopy showed an asymmetric pore structure and indicated that the variation in water flux between membrane sets were probably due to differences in the number of pores per unit membrane area and not to differences in pore diameter. The MW cut-off for all the membranes was found to be close to 66 kD. The permeate flux for standard proteins decreased with increasing protein MW. A decrease in water flux was also observed after the UF runs; this could be explained by membrane fouling.

Defatted waste tuna broth, which was obtained from a fish canning plant as steam condensate after autoclaving fresh tuna, was ultrafiltered using the prepared membranes. The rejection coefficient for either protein or carbohydrate solute of the tuna broth was approximately 54.5% while solute recovery was about 90%. The ultrafiltered broth had negligible turbidity and odor.     

聚氨酯杂化超滤膜的制备及其性能研究

以聚氨酯为基质,添加二氧化硅及界面改性剂,通过湿法相转化法制备聚氨酯杂化超滤膜。实验结果表明,二氧化硅可以显著改善膜孔的结构,膜水通量有较大幅度的提高,二氧化硅用量在一定范围内,截留率也有一定增加。界面改性剂的加入可使二氧化硅在聚氨酯铸膜液中均匀分散,进一步增加聚氨酯与二氧化硅之间的界面微孔数量及细化微孔,使该膜的水通量和截留率进一步增加。用扫描电镜对膜的结构形态进行了观察。     

Tannin and polyacrylic acid polarity and structure influence on the performance of polyvinylchloride ultrafiltration membrane

Tannin and polyacrylic acid were selected to represent the hydrophobic and hydrophilic compounds with similar molecular weights to investigate their fouling characteristics on a polyvinylchloride ultrafiltration membrane and the cleaning efficiencies of the two compounds fouled membranes by three kinds of cleaning methods, i.e., backwashing, flushing&backwashing and 0.5% NaOH solution. The results obtained showed that their configuration optimized by PM3 method of quantum chemistry was significantly different, i.e., tannin was sphere-like, and polyacrylic acid was cylinder-like, though they had similar MW. The hydrophobic tannin, showed higher rejection and rapid permeate flux decline because it was prone to adsorption on membrane pore, resulting in partial flux recovery by hydraulic cleaning and complete recovery by NaOH cleaning. The hydrophilic polyacrylic acid rejection was lower, resulting from its penetrating through membrane pore, cylinder-like-configuration polyacrylic acid can twist in membrane pore passage so that the flux was not recovered by backwashing.     

Effect of additives concentration on the surface properties and performance of PVDF ultrafiltration membranes for refinery produced wastewater treatment

The aim of this study was to investigate the effect of pore-forming hydrophilic additives on the porous asymmetric polyvinylideneflouride (PVDF) ultrafiltration (UF) membrane morphology and transport properties for refinery produced wastewater treatment. PVDF ultrafiltration membranes were prepared via a phase inversion method by dispersing lithium chloride monohydrate (LiCl·H₂O) and titanium dioxide (TiO₂) nanoparticles in the spinning dope. The morphological and performance tests were conducted on PVDF ultrafiltration membranes prepared from a different additive content. The top surface and cross-sectional area of the membranes were observed using a field emission scanning electron microscope (FESEM) and energy dispersive X-ray (EDX) analysis. The surface wettability of porous membranes was determined by the measurement of a contact angle. The mean pore size and surface porosity were calculated based on the permeate flux. The results indicated that the PVDF/LiCl/TiO₂ membranes with lower TiO₂ nanoparticles loading possessed smaller mean pore size, more apertures inside the membrane with enhanced membrane hydrophilicity. LiCl·H₂O has been employed particularly to reduce the thermodynamic miscibility of dope which resulted in increasing the rate of liquid–liquid demixing process. The maximum flux and rejection of refinery wastewater using PVDF ultrafiltration membrane achieved were 82.50 L/m² h and 98.83% respectively at 1.95 wt.% TiO₂ concentration.     

Theoretical analysis of the effects of asymmetric membrane structure on fouling during microfiltration

There is a growing interest in the use of both asymmetric and composite membranes for microfiltration and ultrafiltration processes. This includes particle removal applications in the semiconductor industry and virus clearance in biopharmaceutical applications. Filter fouling plays an important role in these processes. Although flux decline models have been developed for homogeneous membranes, the effects of asymmetric membrane structure on flux decline behavior remain poorly understood on a fundamental level. Here, we develop a theoretical model to describe the effects of asymmetric membrane structure on flux decline. The asymmetric structure was described by the spatial variation in Darcy permeability in the directions normal to and parallel to the membrane surface. The velocity profile and flux decline because of pore blockage were described using Darcy's law and a pore blockage and cake filtration model. Flux decline data were obtained using pseudocomposite membranes with highly interconnected polyvinylidene fluoride membranes (PVDF) and straight through pore polycarbonate track‐etched membranes (PCTE). Model composite membranes were formed by layering PCTE or PVDF membranes with different pore sizes on top of each other. Flux decline data for the composite membrane were in good agreement with model calculations. The results provide important insights into the effects of asymmetric membrane pore structures on flux decline. © 2009 American Institute of Chemical Engineers AIChE J, 2009