正渗透浓缩茶料液中茶多酚研究

采用NaCl溶液作为驱动液,考察了不同的驱动液浓度、不同的膜材料对茶料液中茶多酚的浓缩效果,研究了正渗透过程中膜渗透性能(通量)、膜污染状况、膜清洗效果以及浓缩液中茶多酚的保留率.结果表明:正渗透浓缩茶多酚,以NaCl溶液为驱动液,可以获得较为稳定的通量,采用正渗透浓缩荼多酚具有一定的可行性;以PA-4M、CTA-4M、CTA-2.7M浓缩茶料液,在达到10倍的浓缩倍数时,对污染的膜用NaOH(pH=10)进行清洗25 min,其通量恢复率分别为100％、95.9％、96.1％,浓缩液中茶多酚的保留率分别为70％、79.3％、83.8％;采用CTA膜以2.7 mol/L NaCl溶液为驱动液进行浓缩较为合适.     

正渗透膜分离关键技术及其应用进展

<正>渗透是一种新型的膜分离技术,具有能耗低、膜污染小及回收率高等优点,近年来在国际上得到了广泛的关注.本文介绍正渗透膜分离技术的基本原理;综述正渗透膜分离关键技术驱动液与膜材料的最新进展;简述正渗透膜分离技术的最新应用;展望正渗透膜分离技术的重点研究方向.     

正渗透的机理

正渗透技术是一种新兴的利用渗透原理的膜分离技术,能自发进行,无需外加压力即可实现,为水资源和环境问题提供了低能耗、高效率的解决途径.近年来正渗透技术在国际上得到了广泛的重视,相关的研究正快速发展.文章详细总结了正渗透机理方面的研究进展,深入分析了正渗透的整个动力学过程,为正渗透膜的设计和制备与驱动溶质的选择和开发提供了理论基础.     

正渗透结合真空膜蒸馏技术处理页岩气废水研究进展

介绍本课题组利用正渗透技术处理页岩气废水的研究进展,对正渗透膜材料的制备、驱动液的选择和回收等关键问题进行阐述.分别利用界面聚合法和浸入沉淀相分离法制备正渗透膜材料用于页岩气废水处理,并与商业的HTI膜进行比较.结果显示:界面聚合膜具有更高的通量和盐截留率.页岩气废水经絮凝沉淀和超滤等前处理后,通过FO-VMD集成技术得到可饮用的纯净水,同时对驱动液进行回收并循环利用,实现零排放.     

海藻酸钠修饰磁性纳米粒子驱动液及其正渗透分离性能

通过微乳液共混沉淀法制备了海藻酸钠(SA)修饰的Fe_3O_4磁性纳米粒子Fe_3O_4-SA,该粒子具有良好的分散性和磁响应性.采用红外、透射电镜、磁滞回线和热失重等对磁性纳米粒子的结构和性能进行表征,同时对该磁性纳米粒子与去离子水的混合液作为驱动液时的正渗透(FO)分离性能进行了测试.结果表明,SA成功包覆在Fe_3O_4粒子表面,粒子的粒径约为20 nm,80 g/L的Fe_3O_4-SA磁性纳米粒子与去离子水的混合液渗透压达到1 270 mOSM/L,以此混合液作为FO过程的驱动液时,渗透通量可以达到2.04 L/(m~2·h),并且该驱动液具有较低的反向溶质通量,当驱动液质量浓度为80 g/L时,反向溶质通量约为0.04 g/(m~2·h),大大低于NaCl和SA的反向溶质通量,这说明该驱动液具有较好的FO分离性能.     

正渗透工艺用于微藻生物燃料脱水的研究进展

微藻作为第三代生物能源，在应对传统能源危机方面具有十分巨大的发展潜力。由于微藻脱水能耗巨大，导致后续的微藻生物燃料制备难以实现大规模商业化生产.针对此瓶颈问题，研究人员尝试采用正渗透工艺进行微藻脱水.基于近年来正渗透技术应用于微藻脱水的研究现状，综述了膜污染成因与控制、膜材料开发与膜结构优化、工艺节能增效等方面的研究进展，着重总结了在藻种、正渗透膜以及汲取液等明显影响微藻脱水性能因素方面的研究成果，并指出了未来采用正渗透技术进行微藻脱水的发展趋势.     

正渗透技术应用于污废水处理的研究进展

随着我国污废水处理市场和规模的进一步扩大,同时膜材料生产成本下降,促进了膜技术在废水处理领域的迅速发展.不同于传统施加外压的压力驱动膜处理技术,正渗透以其低能耗、低污染和高截留能力的特点引起了广泛关注.本文从正渗透技术原理出发,介绍了膜材料、汲取液种类和浓差极化3个主要影响因素;其次,分析了正渗透技术及组合工艺在废水处...     

三醋酸纤维素正渗透膜制备过程中影响因素的研究

以三醋酸纤维素为膜材料,以1,4-二氧六环和丙酮为溶剂,乳酸为添加剂.采用相转化法制备三醋酸纤维素正渗透膜.研究了不同支撑材料以及膜制备过程中溶剂挥发时间和添加剂的含量对正渗透膜性能的影响.结果表明,在原料液为0.1 mol/L NaCl,汲取液为4 mol/L葡萄糖,原料液面向分离层,室温的测试条件下,采用180目(80 μm)的筛网为支撑体材料,挥发时间为180 s,乳酸含量为6.6%所制备的三醋酸纤维素正渗透膜的水通量为6～7 L/(m2·h),NaCl截留率在95%以上.     

界面聚合正渗透膜结构参数的调控

<正>渗透过程是以渗透压差为驱动力的膜过程.其中膜的结构参数是决定膜的传质阻力和水通量的关键因素.本文系统介绍了本课题组在调控界面聚合正渗透膜材料结构参数方面的研究进展.利用共混亲水高分子材料调节基膜的亲水性,利用双层刮膜技术调节基膜的孔结构.结果表明利用亲水基膜和具有贯通孔结构的基膜获得FO膜具有更低的膜结构参数,其正渗透性能也更高.     

醋酸纤维素正渗透膜的制备及其性能研究

以醋酸纤维素(CA)作为成膜材料,以聚酯筛网作为支撑材料,利用相转化法制备正渗透膜,考察了正渗透膜制备过程中的影响因素,包括铸膜液中聚合物浓度以及制膜过程中环境湿度、凝胶浴温度及热处理温度对正渗透膜性能(水通量和截盐率)的影响规律。并利用SEM表征了膜表面和断面的形貌。结果表明,在原料液为0.1mol/L NaCl,汲取液为4mol/L葡萄糖,原料液面向分离层,室温的测试条件下,当聚合物浓度为10.4%、在60℃下热处理、凝胶浴温度为15℃、环境湿度为90%时所制备的正渗透膜通量为9.7～10.3L/(m2.h),截盐率在93%以上。     

Energy efficiency of RO and FO–RO system for high-salinity seawater treatment

Forward osmosis (FO) has been proposed as an alternative method for seawater desalination, wherein reverse osmosis (RO) membrane technology is used for regeneration of the draw solution. Previous studies have indicated that a standalone RO unit is more energy efficient than an FO–RO system, and as such it was recommended that an FO–RO system is best employed only for the desalination of high-salinity seawaters. This study examined FO–RO applicability in more detail by examining the impact of seawater salinity, impact of an energy recovery device (ERD), and the effect of membrane fouling. For comparison purposes, the performance of the FO process was improved to minimize the impact of concentration polarization and optimize the concentration of draw solution. Model calculations revealed that FO–RO is more energy efficient than RO when no ERD was employed. However, results showed that there was no significant difference in the power consumption between the FO–RO system and the RO unit at high seawater salinities particularly when a high-efficiency ERD was installed. Moreover, the FO–RO system required more membrane area than a conventional RO unit which may further compromise the FO–RO desalination cost.     

正渗透过程参数对渗透性能的影响

正渗透是新的非热能驱动膜过程。采用界面聚合的方法制备了中空纤维复合膜。以Na2SO4、MgSO4、NaCl和Mg-Cl2水溶液作为驱动液进行了正渗透实验。实验表明,正渗透通量随着驱动液浓度的增加而增加,其中Na2SO4、MgCl2水溶液的渗透通量大于MgSO4、NaCl水溶液的。驱动液中无机盐向原水中扩散的渗透速率随无机盐浓度的增加而增加,且MgCl2>NaCl>Na2SO4>MgSO4。原水流速对正渗透通量的影响极小,而驱动液流速对正渗透通量的影响较大。     

PU/PVDF共混中空纤维膜结构与性能

采用熔体纺丝后拉伸的方法制备了聚氨酯(PU)/聚偏氟乙烯(PVDF)共混中空纤维膜,研究了拉伸对共混膜形态结构的影响,通过测定水通量随透膜压力的变化讨论了PU/PVDF共混中空纤维膜的压力响应性能,并对不同拉伸倍数所得膜压力响应性能差异进行了研究.结果表明,拉伸过程增大了聚合物间界面微孔的通透性,有效地提高了膜的水通量;且随拉伸倍数的提高,PU/PVDF共混中空纤维膜界面微孔的回复性有所提高.     

几种混合导体陶瓷膜反应器的比较研究

用湿化学方法合成了SrCo_0.5FeO_3.25（SC5FO）,La_0.15Sr_0.85Ga_0.3Fe_0.7O3-δ（LSGFO）和Ba_0.5Sr_0.5Co_0.8Fe_0.2O3-δ（BSCFO）三种透氧膜材料.采用H₂-TPR、XRD和透氧测定,并结合膜反应等方法对它们的性质进行了比较研究.LSGFO与BSCFO具有较高的相结构稳定性,而SC5FO较差.LSGFO具有很高的抗还原能力,而BSCFO较差,但它具有优异的相结构可逆性.在air/He氧浓差梯度下,LSGFO和SC5FO导体膜的透氧量较低;BSCFO具有很高的氧渗透能力,850℃下,透氧量高达1.16[STP]mL/cm²·min.SC5FO膜反应器在POM反应开始不久,因为反应端膜表面的材料组成被反应气还原而出现严重的漏气现象,并最终导致实验失败.BSCFO与LSGFO膜反应器成功地应用到POM反应中,进行了长时间的稳定操作,稳态下透氧量分别高达11.5[STP]mL/cm²·min（875℃）与4.0[STP]mL/cm²·min（950℃）.     

Investigating the performance of ammonium sulphate draw solution in fertilizer drawn forward osmosis process

This work investigated the performance of ammonium sulphate as a draw solution in a fertilizer drawn forward osmosis (FDFO) desalination process using thin-film composite (TFC) membrane. Performance has been assessed by the water flux, reverse permeation and the forward rejection of the feed solutes. A logarithmic relation has been determined between flux and ammonium sulphate concentration. As water flux increased, the specific reverse solute flux (SRSF) of NH₄ ⁺ and SO₄ ^2? ions dropped, which is a favourable condition. Reverse permeation values obtained at flux less than 10 L/m²/h are significantly higher than that for flux more than 10 L/m²/h. Thus, it is recommended to operate the process at a flux higher than 10 L/m²/h to avoid loss of draw solute by reverse permeation. SRSF was almost constant irrespective of ammonium sulphate concentration. TFC membrane used in this study exhibited high rejection of feed solution ions for almost all draw solution concentrations except when operated at low ammonium sulphate concentration and high feed solution concentration. In conclusion, ammonium sulphate is an efficient draw solution for FDFO process when run at water flux more than 10 L/m²/h exhibiting high osmotic pressure, low reverse solute permeation and high rejection of feed solute.     

A comparison of sulfur mustard and heptane penetrating a dipalmitoylphosphatidylcholine bilayer membrane

In the present molecular dynamics simulations we study the chemical warfare agent sulfur mustard (bis(2-chloroethyl) sulfide) and the alkane heptane inserted into a dipalmitoylphosphatidylcholine (DPPC) bilayer, a generic model for a biological membrane. We investigate the diffusion, the orientation, the preferred positioning, and the end-to-end distance of the solutes within the membrane as well as the corresponding coupling times. We compare results of equilibrium simulations and simulation at different external forces, which drag the solutes through the membrane. These properties lead to a general comparison of the rotational and translational behaviors of the two solutes during the penetration of the membrane. We show that sulfur mustard, due to its atomic charge polarization, its bigger flexibility and its smaller molecular volume, is the faster moving molecule within the membrane. In last consequence, we show that this leads to different limits for the transport mechanism as observed in these simulations. For heptane the hindrance to penetrate into the membrane is significantly higher than for sulfur mustard. In contrast to heptane molecules, which spend the most of the time penetrating the tail groups, sulfur mustard needs more time to escape the tail group–head group interface of the membrane.     

An Investigation of the Reuse of Liquid Membranes and the Use of a Multidrug Donor Phase in Solute Transport

Complex or multiple emulsions have been investigated for their potential use in pharmaceutics as both drug delivery and drug removal systems. Studies involving previously unused emulsions and single drug donor phases have been described in the literature. The subsequent uptake of solutes using one multiple emulsion or liquid membrane and the co-uptake of solutes from one donor phase were studied. The ability of liquid membranes to remove one solute following removal of another solute was studied for three systems using salicylic acid and phenobarbital at various temperatures. In each case it was observed that the liquid membrane was capable of subsequent drug uptake to varying degrees indicating that the previous use of liquid membranes does not materially affect their further use as sinks. The removal of two drugs from one donor phase using a liquid membrane was studied using acetylsalicylic acid, salicylic acid, and phenobarbital. These systems demonstrated the ability to remove two solutes simultaneously at rates which were of the same magnitude as those measured in single solute systems. The solute combination, initial molar concentration of each solute, and the liquid membrane oil/water ratio were found to influence the apparent rate constants and extent of removal for each drug in the donor phase.     

An Investigation of the Reuse of Liquid Membranes and the Use of a Multidrug Donor Phase in Solute Transport

Abstract

Complex or multiple emulsions have been investigated for their potential use in pharmaceutics as both drug delivery and drug removal systems. Studies involving previously unused emulsions and single drug donor phases have been described in the literature. The subsequent uptake of solutes using one multiple emulsion or liquid membrane and the co-uptake of solutes from one donor phase were studied. The ability of liquid membranes to remove one solute following removal of another solute was studied for three systems using salicylic acid and phenobarbital at various temperatures. In each case it was observed that the liquid membrane was capable of subsequent drug uptake to varying degrees indicating that the previous use of liquid membranes does not materially affect their further use as sinks. The removal of two drugs from one donor phase using a liquid membrane was studied using acetylsalicylic acid, salicylic acid, and phenobarbital. These systems demonstrated the ability to remove two solutes simultaneously at rates which were of the same magnitude as those measured in single solute systems. The solute combination, initial molar concentration of each solute, and the liquid membrane oil/water ratio were found to influence the apparent rate constants and extent of removal for each drug in the donor phase.     

含腐殖酸类有机物模拟废水超滤过程研究

研究了用中空纤维超滤膜组件净化含腐殖酸类有机物模拟废水的过程.考察了料液中Ca2 浓度、离子强度和pH值对超滤过程的影响.实验结果表明,由于Ca2 与腐殖酸分子发生络合反应,随着料液中Ca2 浓度的增大,膜污染程度加剧;料液离子强度的变化改变了腐殖酸分子的构型和溶质分子之间以及溶质分子与膜面之间的相互作用,随着溶液离子强度的增大,膜通量下降程度增大;料液pH值的降低减少了腐殖酸分子链上官能团中H 的离解度,随着pH值的降低,膜污染程度增大;同时,随着料液中Ca2 浓度、离子强度的增大以及pH值的降低,膜对腐殖酸的脱除率降低.