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排序方式: 共有159条查询结果,搜索用时 31 毫秒
41.
Reverse osmosis (RO) is being increasingly used in treatment of domestic wastewater secondary effluent for potable and non-potable reuse. Among other solutes, dissolved biopolymers, i.e., proteins and polysaccharides, can lead to severe fouling of RO membranes. In this study, the roles of RO membrane surface properties in membrane fouling by two model biopolymers, bovine serum albumin (BSA) and sodium alginate, were investigated. Three commercial RO membranes with different surface properties were tested in a laboratory-scale cross-flow RO system. Membrane surface properties considered include surface roughness, zeta potential, and hydrophobicity. Experimental results revealed that membrane surface roughness had the greatest effect on fouling by the biopolymers tested. Accordingly, modified membranes with smoother surfaces showed significantly lower fouling rates. When Ca2+ was present, alginate fouled RO membranes much faster than BSA. Considerable synergistic effect was observed when both BSA and alginate were present. The larger foulant particle sizes measured in the co-existence of BSA and alginate indicate formation of BSA-alginate aggregates, which resulted in greater fouling rates. Faster initial flux decline was observed at higher initial permeate flux even when the flux was measured against accumulative permeate volume, indicating a negative impact of higher operating pressure. 相似文献
42.
HPLC study of the physicochemical characteristics of reverse-osmosis separation on a polyamide membrane material 总被引:2,自引:0,他引:2
Summary The fundamental characteristics of reverse osmosis on a polymer membrane have been correlated with HPLC experimental conditions
by using the membrane material as a column packing. Twelve formulas were used to calculate the physicochemical characteristics
of the reverse-osmosis separation process and it was found that these characteristics can be determined on the basis of retention
(t
R, VR) and partition coefficient (K) of the solute in HPLC. It seems that HPLC is an effective tool for studying the physicochemical nature of reverse-osmosis
separations and the characteristics of the polymer membrane. 相似文献
43.
Ultrathin self-assembled polyelectrolyte multilayer membranes 总被引:3,自引:0,他引:3
B. Tieke F. van Ackern L. Krasemann A. Toutianoush 《The European physical journal. E, Soft matter》2001,5(1):29-39
The paper is concerned with ultrathin membranes prepared upon alternating layer-by-layer adsorption of cationic and anionic
polyelectrolytes on a porous substructure. The formation of the polyelectrolyte multilayer membranes is characterised and
the transport of gases, liquid mixtures and ions across the membranes is studied. In particular, the use of the membranes
for alcohol/water separation under pervaporation conditions, and for the separation of mono- and divalent ions is described.
It is demonstrated that upon a suitable choice of polyelectrolytes and substructures, and a careful optimisation of preparation
and operation conditions, membranes can be tailored exhibiting an excellent separation capability.
Received 4 September 2000 相似文献
44.
Jay B. Benziger May Jean Cheah Vaclav Klika Michal Pavelka 《Journal of Polymer Science.Polymer Physics》2015,53(22):1580-1589
Water and proton transport across a Nafion membrane are measured as functions of water activity and applied electric potential with a polymer electrolyte hydrogen pump. Water and proton transport across the membrane must match water and proton transport entering and leaving the electrode/membrane/vapor three phase interfaces at the anode and cathode. At low applied electric potential proton and water fluxes are correlated. At moderate to high applied electric potential the proton current is constant, independent of applied electric potential, while the water transport increases with increasing electric potential. At high applied electric potential water and proton transport become uncoupled at the membrane interfaces; water is transported across the membrane/vapor interface and protons are transported across the membrane/electrode interface. The applied electric potential drives electro‐osmosis to redistribute the water in the membrane. Water redistribution is limited by the interfacial transport of water across the membrane/vapor interface. © 2015 Wiley Periodicals, Inc. J. Polym. Sci. Part B: Polym. Phys. 2015 , 53, 1580–1589 相似文献
45.
Wonsik Nam Seichang Oh Hyunku Joo Jaekyung Yoon 《Journal of solid state chemistry》2011,184(11):2920-2924
The purpose of this study was to develop effective cathodes to increase the production of hydrogen and use the seawater, an abundant resource in the earth as the electrolyte in photoelectrochemical systems. In order to fabricate the Pt/TiO2 cathodes, various contents of the Pt precursor (0–0.4 wt%) deposited by the electrodeposition method were used. On the basis of the hydrogen evolution rate, 0.2 wt% Pt/TiO2 was observed to exhibit the best performance among the various Pt/TiO2 cathodes with the natural seawater and two concentrated seawater electrolytes obtained from single (nanofiltration) and combined membrane (nanofiltration and reverse osmosis) processes.The surface characterizations exhibited that crystal structures and morphological properties of Pt and TiO2 found the results of XRD pattern and SEM/TEM images, respectively. 相似文献
46.
47.
Yi-Ning Hu Qiao-Mei Li Yan-Feng Guo Li-Jing Zhu Zhi-Xiang Zeng Zhu Xiong 《Journal of polymer science. Part A, Polymer chemistry》2021,59(11):1065-1071
Here, polyvinylidene fluoride (PVDF) membranes were fabricated via non-solvent induced phase separation (NIPS) using dopamine (DA) and polyethyleneimine (PEI) as the hydrophilic additives, which has a loose surface and somewhat improved hydrophilicity. Then nanofiltration (NF)-like thin-film composite forward osmosis (TFC FO) membrane with a loose polyamide (PA) active layer on the blend membrane was synthesized via the interfacial polymerization. The as-prepared NF-like TFC FO membrane exhibited a high water flux (Jw) of 29.98 L m−2 h−1 and a much low specific salt flux (Js/Jw) of 0.018 g/L, when 0.6 M NaCl was used as draw solution (DS). It had a superior rejection of malachite green (99.6% ± 0.1%) and a low rejection of NaCl (27.4% ± 4.2%), when filtrated malachite green/NaCl mixture solution in active layer-facing draw solution (AL-FS) mode. The results provide new insights on the design and preparation of FO membranes of selective separation for dyes from salty water. 相似文献
48.
本研究提出的强渗磨圆球率测定方法,将GB/T12958-1990中已有的树脂强度测定方法(渗磨圆经)中的渗透压冲击由一个周期增加为五个周期,以便更加实地反映凝结水处理树脂在实际使用中在强度方面的差别。对国内主要树脂厂家生长的凝结水处理用强酸,强碱各9种样品的测定结果表明,78%的强酸树脂和56%的强碱树脂的强渗磨圆球率可达到或大于90%的指标,大型型树脂的强渗磨圆球率一般高于凝胶型均粒树脂。该测定方法已作为电力行业标准-《火电厂水处理用离子交换树脂选用导则》的“标准的附录”。 相似文献
49.
Novel thin-film composite membranes with improved water flux from sulfonated cardo poly(arylene ether sulfone) bearing pendant amino groups 总被引:3,自引:0,他引:3
A new class of polymeric amine, namely, sulfonated cardo poly(arylene ether sulfone) (SPES-NH2) was synthesized and used for the preparation of thin-film composite membrane. The TFC membranes were prepared on a polysulfone supporting film through interfacial polymerization with trimesoyl chloride (TMC) solutions and amine solutions containing SPES-NH2 and m-phenylenediamine (MPDA). The resultant membranes were characterized with water permeation performance, chemical structure, hydrophilicity of active layer and membrane morphology including top surface and cross-section. The membrane prepared under the optimum condition showed the salt rejection and water flux reached 97.3% and 51.2 L/m2 h, respectively. The high salt rejection and water flux was attributed to the rigid polymer backbone and the presence of strong hydrophilic sulfonic groups. 相似文献
50.
Preparation of thin-film-composite polyamide membranes for desalination using novel hydrophilic surface modifying macromolecules 总被引:1,自引:0,他引:1
Belal J. Abu Tarboush D. Rana T. Matsuura H.A. Arafat R.M. Narbaitz 《Journal of membrane science》2008
A new concept for the preparation of thin-film-composite (TFC) reverse osmosis (RO) membrane by interfacial polymerization on porous polysulfone (PS) support using novel additives is reported. Hydrophilic surface modifying macromolecules (LSMM) were synthesized both ex situ by conventional method (cLSMM), and in situ within the organic solvent of the TFC system (iLSMM). The effects of these LSMMs on the fouling of the TFC RO membranes used in the desalination processes were studied. FTIR results indicated that both cLSMM and iLSMM were present in the active layer of the TFC membranes. SEM micrographs depicted that heterogeneity of the surface increases for TFC membranes compared to the control PS membrane, and that higher concentrations of LSMM provided smoother surface. AFM characteristic data presented that the surface roughness of the skin surface increases for TFC membranes compared to the control. The RO performance results showed that the addition of the cLSMM significantly decreased the salt rejection of the membrane and slightly reduced the flux, while in the case of the iLSMM, salt rejection was improved but the flux declined at different rates for different iLSMM concentrations. The membrane prepared by the iLSMM exhibited less flux decay over an extended operational period. 相似文献