共查询到20条相似文献,搜索用时 15 毫秒
1.
2.
3.
pH对膜污染层EPS污染特征的影响及机理分析 总被引:1,自引:0,他引:1
溶液pH值不仅影响溶质的电荷等表面性质,同时也影响膜表面的特性,从而影响溶质与膜表面之间的相互作用和溶质在膜面的沉积量及膜通量.胞外多糖(Extracellular POlvsac-charides,EPS)是膜生物反应器(Membrane Bioreactor,MBR)中主要的膜污染物质之一,从实际MBR膜污染层中分离纯化得到的EPS,在EPS引起膜污染机理分析的基础上,以过滤阻力、EPS在膜表面沉积量及膜通量为评价指标,综合分析不同溶液pH对EPS污染特征的影响,可为揭示MBR中EPS膜污染的成因和机理以及污染膜的清洗提供参考.结果表明,MBR膜污染层EPS的膜污染过程较好地符合沉积阻力模型,EPS在膜表面的污染主要是EPS沉积引起的;EPS溶液的pH越高,其与膜之间的排斥力越大,沉积量越少,沉积阻力越小,膜通量越高.pH为7.0时,沉积阻力为3.34×10~(11) m~(-1),沉积量为1.25 g/m~2,初始相对膜通量为9.8%. 相似文献
4.
5.
填充型渗透蒸发膜的材料选择和制备 总被引:4,自引:0,他引:4
填充型渗透蒸发膜将填充剂的高吸附容量和膜过程的连续性的优势有效集成.以创造出适宜的膜结构形态并赋予膜以新颖和期望的理化特性,从而提高膜的渗透通量、选择性和力学强度等,因而在有机物脱水、水中有机物脱除和有机物-有机物分离等领域具有良好的应用前景。文中从膜的分类,膜材料的选择以及膜的制备方法三个方面对填充型渗透蒸发膜进行简要评述。 相似文献
6.
7.
8.
采用溶液相转化法制备了羽绒粉体/聚偏氟乙烯(PVDF)和苎麻粉体/PVDF复合微孔膜,对膜结构和性能进行了分析和测试。结果显示苎麻粉体/PVDF复合膜、羽绒粉体/PVDF复合膜、纯PVDF膜的形态一致,均为致密皮层和多孔亚层,孔隙率和水通量依次降低,结晶度依次增加;但膜的吸水率按照羽绒粉体/PVDF复合膜、苎麻粉体/PVDF复合膜、纯PVDF膜依次下降;这说明复合膜水通量主要受孔隙率的影响,而膜吸水率主要受纤维粉体吸水性大小的影响。膜力学性能测试显示加入粉体之后,PVDF膜的强度增加,断裂伸长率有所下降。 相似文献
9.
10.
11.
阳极氧化铝膜在分离方面有许多优点如均一的孔径、高的热力学稳定性、独特的孔结构等,作为无机膜有较好的商业应用价值,但膜的脆性问题一直是公认的难题.用一次阳极氧化铝膜的铝面做阳极在盐酸中电解后,再在磷酸中扩孔,制得了两面贯通以大孔铝为支撑体的阳极氧化铝膜.研究了扩孔时间对膜的纯水通量、平均孔径、截留率的影响.结果表明,膜的平均孔径为65.5~119.2 nm;膜的孔径分布窄,孔隙率为28.6%~32.7%;随着扩孔时间的增加,膜的平均孔径、纯水通量均增大,而膜对聚乙二醇20 000的截留率减小;当扩孔时间为30min时,对聚乙二醇20 000截留率达到了26.5%;膜的纯水通量随着时间的增加而减小;膜的脆性问题在一定程度上得以改善. 相似文献
12.
13.
新型CO2分离膜的结构和性能 总被引:6,自引:0,他引:6
研制成功一种对CO2具有促进传递作用的新型膜材料-聚乙烯胺,将此膜材料覆盖在聚砜膜表面复合膜,考察了复合膜的多层结构,复合膜对CO2、CH4、N2等的吸着性能,及复合膜对CO2和CH4的分离进透过性能。结果表明,该复合膜对CO2有很高的吸着量,而对其他测试气体仅有极微弱的吸着;对CO2/CH4体系该复合膜具有良好的分离的能力。 相似文献
14.
15.
采用相转化法制得了氯甲基化聚砜(CMPSF)微孔滤膜,以乙二胺为试剂对CMPSF膜进行化学改性,膜表面的伯胺基与水溶液中的过硫酸铵构成表面引发体系-NH_2/S_2O_8~(2-),使叔胺单体甲基丙烯酸二甲基氨基乙酯(DMAEMA)发生接枝聚合,获得了多孔接枝膜PSF-g-PDMAEMA。考察了接枝聚合的规律,对接枝膜进行了充分表征,考察研究了接枝膜对2种毒性阴离子CrO_4~(2-)及MoO_4~(2-)离子的吸附性能和膜分离去除行为。研究结果表明,控制水溶液中过硫酸铵的质量分数为1%,温度为50℃,可制得PDMAEMA接枝度为0.64 mg/cm~2的接枝膜。在酸性及中性水溶液中,凭借强烈的静电相互作用,多孔接枝膜PSF-g-PDMAEMA对毒性阴离子CrO_4~(2-)离子及MoO_4~(2-)离子均会产生强吸附作用;以该多孔接枝膜为滤膜进行膜分离过程,通过选择性吸附,可有效地去除水介质中的CrO_4~(2-)离子。 相似文献
16.
17.
18.
Hisamoto H Shimizu Y Uchiyama K Tokeshi M Kikutani Y Hibara A Kitamori T 《Analytical chemistry》2003,75(2):350-354
Here we report a design and synthesis of a chemically functional polymer membrane by an interfacial polycondensation reaction and multilayer flow inside a microchannel. Single and parallel dual-membrane structures are successfully prepared by using organic/aqueous two-layer flow and organic/aqueous/organic three-layer flow inside the microchannel followed by an interfacial polycondensation reaction. By using the inner-channel membrane, permeation of ammonia species through the inner-channel membrane is successfully achieved. Furthermore, horseradish peroxidase is immobilized on one side of the membrane surface to integrate the chemical transform function onto the inner-channel membrane. Here substrate permeation through the membrane and subsequent chemical transformation at the membrane surface are realized. The polymer membrane prepared inside the microchannel has an important role in ensuring stable contact of different phases such as gas/liquid or liquid/ liquid and the permeation of chemical species through the membrane. Furthermore, membrane surface modification chemistry allows chemical transformation of permeated chemical species. These methods are expected to lead to development of complicated and sophisticated chemical systems involving membrane permeation and chemical reactions. 相似文献
19.
壳聚糖-硫酸软骨素共混膜性质的研究 总被引:13,自引:0,他引:13
以溶液共沸法制成不同共混比例的壳聚糖-硫酸软骨素共混膜,通过观察共混膜的表面形态结构、结晶度、红外吸收及透光率,发现壳聚糖和硫酸软骨素两种分子具有较好的相容性,分子间具有较强的相互作用,所形成的共混膜表面结构均匀单一。通过研究共混膜的各种性质发现硫酸软骨素的混入可以改善膜的力学特性,提高膜的透光性及渗透性,降低膜的吸水性及对蛋白的吸附性。以共混膜为载体培养兔角膜内皮细胞,发现硫酸软骨素的引入可明显提高膜和细胞的相容性,兔角膜内皮细胞可在膜上长期生长,结果提示此共混膜可作为细胞培养的良好载体,用于器官损伤修复及细胞移植。 相似文献
20.
Jorn A. Cheney Nicolai Konow Andrew Bearnot Sharon M. Swartz 《Journal of the Royal Society Interface》2015,12(106)
Bats fly using a thin wing membrane composed of compliant, anisotropic skin. Wing membrane skin deforms dramatically as bats fly, and its three-dimensional configurations depend, in large part, on the mechanical behaviour of the tissue. Large, macroscopic elastin fibres are an unusual mechanical element found in the skin of bat wings. We characterize the fibre orientation and demonstrate that elastin fibres are responsible for the distinctive wrinkles in the surrounding membrane matrix. Uniaxial mechanical testing of the wing membrane, both parallel and perpendicular to elastin fibres, is used to distinguish the contribution of elastin and the surrounding matrix to the overall membrane mechanical behaviour. We find that the matrix is isotropic within the plane of the membrane and responsible for bearing load at high stress; elastin fibres are responsible for membrane anisotropy and only contribute substantially to load bearing at very low stress. The architecture of elastin fibres provides the extreme extensibility and self-folding/self-packing of the wing membrane skin. We relate these findings to flight with membrane wings and discuss the aeromechanical significance of elastin fibre pre-stress, membrane excess length, and how these parameters may aid bats in resisting gusts and preventing membrane flutter. 相似文献