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采用Co^60辐射引发丙烯酸接枝和PVDF中空纤维膜自交联,用IR谱图证实了丙烯酸接枝到中空纤维膜上.由SEM显示,低辐射剂量率有利于接枝链在膜表面的均匀分布,接枝率随辐射剂量率增加而下降,随单体浓度增加先上升,单体体积分数达到20%左右后接枝率反而下降;接枝膜的拉伸断裂强度随接枝率的增加而提高,但是辐射自交联无法显著提高膜的力学性能. 相似文献
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Ultrafiltration hollow-fiber membranes (UHFMs) ofpoly(acrylonitrile-co-malefic acid) (PANCMA) were prepared by a dry-wet phase inversion process. The morphologies of inner surface and cross section for these hollow fibers were inspected with scanning electron microscopy. It was found that, by increasing the amount of solvent DMSO in internal coagulant, the number and size of macrovoid underneath the inner surface decreased. The water flux of the UHFMs also decreased while the bovine serum albumin rejection increased minutely. These results were interpreted based on the ternary phase diagrams for the PANCMA/DMSO/(H2O+DMSO) system, which was obtained from the experimental cloud point measurements and empirical linearized cloud point relation. It was envisaged that the membrane surface could be further modified by the reaction of acid groups with poly(ethylene glycol). 相似文献
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膜生物反应器研究进展 总被引:4,自引:0,他引:4
本文概括分析了膜生物反应器的特征、类型和功能,对其在发酵、动植物细胞培养帮生物催化等过程中的应用和发展做了介绍和讨论。 相似文献
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We have found that the chemistries of inner and external coagulants, gelation bath temperature, and air gap distance have profound effects on 6FDA-polyimde hollow-fiber morphology and performance. This 6FDA-polyimide is made of 50 mol % 2,2′-bis(3,4′-dicarboxyphenyl) hexafluoro propane dianhydride (6FDA) and 50 mol % 2,2′-bis(3-aminophenyl) hexafluoro propane (4,4′ 6F-diamine) (6FDAM). An increase in air gap distance tends to induce three-dimensional open-cell pore formation. Raising bath temperature has a similar effect. Multilayer finger-void structure can be completely eliminated if one properly chooses a bore-fluid flow rate and a gelation bath temperature. Experimental data demonstrate that the location of the dense layer can be shifted from the inner skin to the outer skin based on the chemistry (solubility parameter) of coagulants. The location of finger voids is also dependent on the chemistry of coagulants, and the dense layer location may shift from the inner surface to the external surface or appear in both surfaces dependent on the differences in solubility and coagulation rate. A defect-free 6FDA/6FDAM polyimide fiber with a selectivity of 4.73 and a permeance of 38.1 GPU is produced. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65:1555–1569, 1997 相似文献
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Abstract An extraction and simultaneous back-extraction process with two hollow-fiber membrane contactors is evaluated for the continuous recovery of alkali metals and 1,3 bis-benzo-crown-6-calix[4]arene. The results show that this configuration operates as a “liquid membrane” (permeable only with alkali picrate) and order of the recovery yields is in agreement with the Donnan equilibrium. It is higher for the rubidium (75.8%) than for the cesium (68.1%) while it is only 11% for the potassium. This is a case where the high affinity of cesium picrate for the 1,3 bis-benzo-crown-6-calix[4]arene cannot be neglected and, as a consequence, its release in the back-extraction aqueous phase is more difficult. The effect of the alkali metal and the initial concentration on the system behavior shows that the concentration gradient controls the mass transfer. The kinetics are similar for the cesium and the rubidium whereas the mass-transfer resistance increases for the potassium. A high mass transfer in the first module can slow down the global-transport kinetics. 相似文献
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Akio Shibasaki Yasumitsu Irimoto Min Kim Kyoichi Saito Kazuyuki Sugita Takashi Baba Isao Honjyo Shigeru Moriyama Takanobu Sugo 《Journal of the American Oil Chemists' Society》1999,76(7):771-775
Silver ions were loaded at a density of 1 mmol/g onto a sulfonic acid group-containing porous hollow-fiber membrane prepared
by radiation-induced graft polymerization of an epoxy group-containing monomer with subsequent modification by reaction with
sodium sulfite. The permeability (i.e., permeation flow rate per inside surface area of the hollow fiber) of 4.6% wt/vol bonito
oil ethyl ester solution in water/ethanol (7.5:92.5, vol/vol) was 1.7 m/h at a permeation pressure of 0.1 MPa. Breakthrough
curves (i.e., concentration changes of the effluent with increasing effluent volume) obtained with docosahexaenoic acid ethyl
ester (DHA-Et) overlapped, irrespective of the permeation flow rate. This indicates that a higher rate of DHA-Et adsorption
onto the silver ions on the membrane was attained with increasing permeation flow rate. DHA-Et, which was selectively bound
to the membrane, was quantitatively eluted with acetonitrile as an eluent. The adsorption characteristics (i.e., binding rate,
selectivity and durability for repeated use) of DHA-Et using the silver ion loaded porous hollow-fiber membrane were demonstrated.
Feasibility studies will enable comparison of the purification cost of DHA-Et among the other purification techniques. 相似文献
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聚偏氟乙烯中空纤维膜的改性研究 总被引:12,自引:0,他引:12
采用化学接枝方法对聚偏氟乙烯(PVDF)中空纤维膜进行亲水改性,采用红外光谱、X射线光电子能谱和扫描电子显微镜等对接枝层进行测试、表征,实验结果表明,PVDF中空纤维膜与2-丙烯酰胺-2-甲基丙磺酸发生了接枝反应,接枝物可有效提高PVDF中空纤维膜的亲水性;改性后PVDF中空纤维膜含水率提高至112.3%;pH值和溶液离子浓度对改性的PVDF中空纤维膜的通量有较为明显的影响。 相似文献