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1.
PSF-SPES共混中空纤维超滤膜制备的研究   总被引:5,自引:0,他引:5  
以聚砜(PSF)、磺化聚醚砜(SPES)和醋酸纤维素(CA)为膜材料,水为内凝胶剂,采用干湿法制备了PSF-SPES共混中空纤维超滤膜,探讨了PSF-SPES铸膜液中SPES离子交换容量(IEC)、SPES浓度、添加剂、外凝胶剂的选择和热处理对膜性能的影响。所得共混超滤膜性能如下:w=0.0 0 1的Na2SO4截留率19.9%,通量62 L/(h.m2.MPa);w=0.001的PEG4000截留率78.2%,通量85 L/(h.m2.MPa)。此外,以PSF-SPES中空纤维为支撑膜,采用醋酸纤维素作为涂层液,研究了CA/PSF-SPES复合超滤膜性能,讨论了CA/PSF-SPES共混中空纤维超滤膜结构。  相似文献   

2.
以静电纺丝技术制备的同轴聚甲基丙烯酸十八烷基酯(PSMA)/聚对苯二甲酸乙二酯(PET)纳米储能纤维为支撑层,经聚偏氟乙烯(PVDF)涂覆成膜和溶剂化处理,制备了一种低压高水通量的纳米储能纤维复合过滤膜(NFCM),其中以水或乙醇为凝固溶液的复合过滤膜分别记为NFCM@H2O或NFCM@EtOH.分析并讨论了不同溶剂处理方式对NFCM力学性能和表面形貌的影响,表征了膜的纯水通量和抗污性能,用扫描电子显微镜(SEM)观察了膜的横断面形貌.结果表明,PSMA/PET纳米储能纤维具有明显的吸放热行为,熔融温度和热焓值分别为36.5℃和10.7J/g,NFCM的熔融温度和热焓值分别为36℃和2.7J/g.NFCM的形貌结构、纯水通量和截留率与溶剂处理方式相关,NFCM@EtOH膜的水通量介于100~1400L/(m2·h)之间,而NFCM@H2O膜的水通量仅在40~220L/(m2·h)之间.NFCM的拉伸强度由初始0.925MPa(PVDF)提高到4.28MPa以上.NFCM中的相变材料对膜过滤性能有重要影响,并在过滤温度低于50℃时具有减缓作用.  相似文献   

3.
以聚间苯二甲酰间苯二胺(PMIA)为成膜聚合物,N,N-二甲基乙酰胺(DMAc)为溶剂,氯化钙(Ca Cl2)、氯化锂(Li Cl)和聚乙二醇(PEG)为添加剂,调制铸膜液,采用干—湿法纺丝技术制备了PMIA中空纤维膜.研究表明,PEG的加入可显著提高PMIA中空纤维膜的纯水通量,而随PEG添加量增加,膜的纯水通量呈现先增加后减小趋势;膜对牛血清蛋白(BSA)有较好的截留性能,截留率可达92%;膜具有良好的亲水性能,膜对纯水接触角可低至44°;膜的断裂强度达5.8 MPa,具有较好的力学性能,以及良好的耐热水和耐碱性能,可用于高温和碱性水处理等领域.  相似文献   

4.
采用二维编织技术将聚丙烯腈(PAN)长丝编织成中空纤维编织管作为增强体,分别以聚丙烯腈(PAN)和聚偏氟乙烯(PVDF)为成膜聚合物,N,N-二甲基乙酰胺(DMAc)为溶剂,聚乙烯吡咯烷酮(PVP)为添加剂,调制铸膜液,采用同心圆挤出-涂覆法制备了PAN纤维编织管同质增强型PAN中空纤维膜和异质增强型PVDF中空纤维膜.研究表明,所得PAN纤维编织管增强型中空纤维膜断裂强度最大可超过75 MPa,在伸长率10%范围内,表面分离层与增强体之间界面结合良好;表面分离层具有类似于非对称膜的结构,铸膜液可浸入纤维编织管纤维空隙中,铸膜液浸入部分固化后未影响膜的通透性能;随成膜聚合物浓度增加,膜纯水通量减小,牛血清白蛋白(BSA)截留率增大;随添加剂PVP浓度增加,膜的纯水通量先增大后减小,在8 wt%左右达最大值,BSA截留率随PVP浓度增加而单调增加;同质增强型中空纤维膜界面结合程度优于异质增强型.  相似文献   

5.
以离子液体氯代1-烯丙基-3-甲基咪唑([AMI M]Cl)为溶剂纺制纤维素中空纤维膜,考察了聚乙二醇(PEG)分子量及其质量分数对中空纤维膜结构与性能的影响。采用场发射扫描电子显微镜(FESEM)对膜内、外表面形态结构进行了观察,测试了中空纤维膜的水通量、截留率等渗透性能以及最大拉伸强度、断裂伸长率等力学性能。结果表...  相似文献   

6.
吉欣  王坤鹏  张利娟  张琳 《化学研究》2005,16(3):65-66,70
用截留分子量不同的中空纤维超滤膜组件对梨醋半成品进行了处理.结果表明,使用截留分子量为1万的中空纤维超滤膜组件,在0.1 MPa压力差和室温下,将梨醋半成品超滤5 h,透过通量基本恒定在6 L/(m2.h).梨醋经过超滤,酸度保留率可达97.4%,糖度保留率88.3%,且风味不变,澄清透明,放置13个月无沉淀物.  相似文献   

7.
低截留分子量PPES超滤膜的制备   总被引:1,自引:0,他引:1  
以杂萘联苯聚醚砜(PPES)为膜材料、N-甲基吡咯烷酮(NMP)为溶剂、有机小分子丙醇(PrOH)和无机小分子氯化锂(LiCl)作为混合添加剂,采用相转化法制备超滤膜.研究了聚合物浓度、混合添加剂配比、凝胶浴温度等对膜结构和性能的影响.结果表明:随聚合物浓度的增大,膜的纯水通量下降,截留率升高;混合添加剂,在PrOH含量为12%、LiCl含量为1.5%时,可制得纯水通量为252 L/(m2·h),对聚乙二醇1000(PEGl000)截留率为96%的超滤膜;随凝胶浴温度的升高,膜的纯水通量增加.  相似文献   

8.
以N,N-二甲基乙酰胺(DMAc)为溶剂,水为外凝固浴,乙醇为内凝固浴,DMAc为内凝固浴添加剂,采用相转化法制备了聚醚酰亚胺(PEI)中空纤维膜,研究了内凝固浴组成和纺丝液浓度对膜结构和性能的影响。实验结果表明,随着内凝固浴中DMAc含量在一定范围内增加,纤维断面指状孔有所减少,内表面由无孔到有微孔出现,但膜的水通量下降,截留率不受影响;随着纺丝液浓度提高,膜的水通量下降,截留率提高。  相似文献   

9.
中空纤维膜因其体积装填密度高、占地面积小、成本相对低等优点备受关注。本文通过将Armos聚合液与聚砜(PSf)共混,经干-湿法纺丝制备了Armos/PSf共混中空纤维超滤膜,研究表明:Armos均匀分散在中空纤维膜中,中空纤维膜断面呈现疏松的多孔结构,随着Armos共混含量的增加,膜的亲水性和纯水通量均提高,但对PEG-20000截留率下降明显。以Armos/PSf共混中空纤维膜为基膜,通过界面聚合制备了中空纤维复合纳滤膜,优化的制备条件为:基膜中Armos的共混含量为4%、水相单体浓度为3%、油相单体浓度为0.15%时,制得的中空纤维复合纳滤膜性能最佳,其通量为8.40L/(m2·h),对MgSO4的截留率为88%。  相似文献   

10.
抗油污染α-纤维素中空纤维超滤膜油-水分离性能的研究   总被引:7,自引:0,他引:7  
以α-纤维素为原料,一水合N-甲基吗琳-N-氧化物(NMMO.H2O)为溶剂,聚乙二醇(PEG400)为添加剂,去离子水为内外凝胶浴,采用浸入相转化法制备用于油水分离的中空纤维非对称超滤膜,并采用纯水通量表征了膜的性能.用纤维素中空纤维超滤膜进行油水分离实验,油水乳液的截留率可达到99%以上,渗透液含油量小于10 mg/L,达到国家环境保护排放要求.考察了物理清洗、物理清洗加0.1 mol/L HCL清洗、物理清洗加0.1 mol/L NaOH清洗3种清洗方法对油水污染后膜的清洗效果.其中,物理清洗加0.1 mol/LNaOH清洗的清洗方法的通量恢复率达到99%.与其它种类的膜相比,α-纤维素中空纤维膜的油水通量衰减率仅为9.5%,表现出优异的抗油污染性能.  相似文献   

11.
用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.  相似文献   

12.
In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.  相似文献   

13.
A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.  相似文献   

14.
The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp3)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp2)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp2)?H and aliphatic 1,5- and 1,6-C(sp3)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp3)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp2)?H insertion.  相似文献   

15.
The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.  相似文献   

16.
KMnO4-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.  相似文献   

17.
The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.  相似文献   

18.
The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.  相似文献   

19.
N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).  相似文献   

20.
An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y1 and Y2. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.  相似文献   

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