首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 62 毫秒
1.
硅橡胶均质膜是渗透蒸发透醇膜的典型代表之一,因其机械性能较差、成膜性不好,分离性能受到限制。本文用物理涂敷(复合)和化学改性的方法,制备出了机械性能优良且具有超薄活性层的硅橡胶改性复合膜,明显改善了分离性能。在最佳条件下,分离系数和透过通量分别为6.78和1080g/m^2h。  相似文献   

2.
以脱乙酰化度为77.5%的壳聚糖为原料,分别将CS膜,CSA/PAN膜,CS-PVA/PAN膜用于乙醇/水混合物的分离,研究了原料组成,温度,膜厚等的影响,结果表明,这些膜均具有良好的分离性能,其中CS-PVA/PAN膜具有最优的渗透选择性。  相似文献   

3.
报道了以硅沸石(Silicalite)为原料,添加结晶模板剂TPABr(4-n-丙基溴铵)以及碱源(NaOH)等,利用水热合成法成功地合成了高硅含量、疏水性硅沸石膜.同时探讨了硅沸石膜对各种含醇水溶液的渗透气化分离特性.研究结果表明:对乙醇/水溶液,供给液乙醇浓度4.7%(wt)时,透过液乙醇浓度达到76%(wt)以上,分离系数αe/w)达65以上;对酒精发酵液,供给液乙醇浓度4.8%(wt)时,透过液乙醇浓度达到82%(wt)以上,分离系数α(e/w)高达90以上.充分说明了所合成的硅沸石膜对酒精水溶液具有非常高的分离效果.  相似文献   

4.
MFI型沸石填充硅橡胶分离膜的制备、结构与性质   总被引:1,自引:0,他引:1  
用ZSM-5沸石或硅沸石(silicalite-1)填充硅橡胶制成了疏水性分离膜,它对有机溶剂/水系统的渗透蒸发性能与膜的组成、结构以及吸附、脱附行为有关.所填充的沸石结构性质(如硅铝比、阳离子、Si-OH缺陷以及结晶度等)是影响膜分离性能的关键因素.用结构完美、疏水性优良的硅沸石制备的填充膜其乙醇/水的分离系数α可达30.基材硅橡胶本底的分离性质也影响填充膜的性能.填充膜对正丙醇/水、异丙醇/水、丙酮/水系统的分离效果不同与这些有机分子的分子尺寸及极性有关.本文还研究了填充膜的机械性能随填充量改变的规律.  相似文献   

5.
用ZSM-5沸石或硅沸石填充硅橡胶制成了疏水性分离膜。它对有机溶剂/水的渗透蒸发性能与膜的组成、结构以及吸附、脱附行为有关。所填充的沸石结构性质是影响膜分离性能的关键因素。用结构完美、疏水性优良的硅沸石制备的填充膜其乙醇/水的分离系α可达30.基村硅橡胶本底的分离性质也影响填充膜的性能。  相似文献   

6.
在硅橡胶中加入交联剂,制备成有机硅膜.该膜对醇-水混合物具有良好的分离性能,实验表明:交联剂的用量,交联方式均对膜性能有很大的影响,膜内支撑材料和料液浓度对膜的渗透性能也有影响,HV法和RTV法制得的透醇膜对酒精的选择因子分别约为7和5,其通量分别约为15×10-3kg/(m2·h)和40×10-3kg/(m2·h).  相似文献   

7.
聚氨酯微孔膜的防水透湿性及电镜分析   总被引:9,自引:0,他引:9  
以聚氨酯微孔膜的电膜照片,分析在不同组成和不同的成型条件下制取的膜的结构和性能,得到了采用配比为10/05/05的NN二甲基甲酰胺/四氢呋喃/乙二醇的混合溶剂和高温分级快干条件下形成的PU膜.该膜具有细密微孔结构和优良的防水透湿性  相似文献   

8.
PVC/PVB共混超滤膜性能研究及应用   总被引:2,自引:0,他引:2  
通过将两种羟基含量相同、黏度不同的PVB,分别与PVC进行共混制备微孔膜,可以改善PVC膜性能.利用扫描电镜(SEM)对PVC/PVB共混膜进行了微观结构分析,并测试了PVC/PVB共混膜水通量和截留率.结果表明:加入PVB后改变了铸膜液的分相过程,从共混膜SEM照片的断面结构可见其皮层厚度增加,指状孔减少,且形成较多的界面微孔;两种PVC/PVB共混膜性能有一定的改善,水通量及截留率均有不同程度的提高.并且利用制备的PVC/PVB膜对造纸黑液进行了处理.  相似文献   

9.
以脱乙酰化度为77.5%的壳聚糖为原料,采用高温浓碱处理的方法得到脱乙酰化度为98.2%的壳聚糖,分别用这两种壳聚糖制膜,用于乙醇/水混合物的分离结果表明,在同样条件下,脱乙酰化度高的壳聚糖膜的分离性能优于脱乙酰化度低的壳聚糖膜。  相似文献   

10.
以乙醇水溶液为分离对象,研究了聚丙烯酸(PAA)与聚酰胺羧或聚乙烯醇(PVA)共混膜的渗透蒸发分离性能,以及均相,非均相缩醛反应对PVA膜分离因素α和渗透通量J的影响。实验发现,戊二醛交联PVA膜的α提高 到49.5(乙醇含水C1=10%,温度为55℃);增加非均相缩甲醛反应时间,PVA/PAA共混膜的α先下降而后趋于不变,同时J存在一最大值。  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

13.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

14.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

15.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

16.
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that  相似文献   

17.
For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the  相似文献   

18.
Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of  相似文献   

19.
<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with  相似文献   

20.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号