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采用电子束辐照的方法制备了聚甲基丙烯酸二甲氨基乙酯(PDM)/聚砜(PSF)中空纤维复合纳滤(NF)膜。研究了PDM水溶液的浓度、预涂膜的干燥时间、辐照时间、辐照剂量等制备条件与纳滤膜截留性能的关系。实验得到中空纤维内压纳滤膜对1g/LMgSO4的截留率为84.8%,对0.5g/LNaCl的截留率为12.8%。对纳滤膜截留性能的研究表明:(1)纳滤膜对阴离子的截留率与香农半径的变化规律相同,而阳离子相反,阴离子的价态对截留率的影响较小,而阳离子的价态对截留率的影响较大;(2)纳滤膜可实现单糖与多糖分离;(3)纳滤膜能有效截留纺丝废水中的[Amim]Cl。采用流动电位法研究纳滤膜的表面动电现象,研究了浓度和压力对膜的表面Zeta电位和电荷密度的影响。结果表明,纳滤膜的表面流动电位的绝对值(ΔE)和表面Zeta电位的绝对值(ζ)均随电解质溶液浓度和压力的增加而减小;ΔE在不同电解质溶液中的顺序为NaCl>MgCl2>KCl>KBr>Na2SO4>MgSO4;表面电荷密度的绝对值(σd)随电解质溶液浓度的增加而增加,随压力的增加而降低。采用流动电位法研究了功能层结构与纳滤膜截留性能的关系。实验表明,流动电位法可用于研究复合纳滤膜的截留机理和功能层结构。流动电位法可以得到膜表面电学参数,如流动电位(ΔE)、Zeta电位(ζ)和表面电荷密度(σd),这些参数的变化与功能层交联时间和纳滤膜截留率的变化一致。复合纳滤膜的ξ按照Na2SO4>MgSO4>MgCl2增加,同截留率的变化一致。带侧基单体交联后得到的纳滤膜的表面电性能参数的绝对值小于不带侧基单体的。
Poly (N-ethylmethacrylate) (PDM) / polysulfone (PSF) hollow fiber composite nanofiltration (NF) membranes were prepared by electron beam irradiation. The concentration of PDM aqueous solution, the drying time of precoating film, the irradiation time, the irradiation dosage and other preparation conditions were studied. Obtained hollow fiber membrane nanofiltration membrane 1g / LMgSO4 rejection of 84.8%, 0.5g / LNaC retention rate of 12.8%. The results showed that: (1) The retention rate of anion on nanofiltration membrane was the same as that of Shannon radius, while on the contrary, the valence of anion had little effect on the rejection, while the valence of cation (2) Nanofiltration membrane can separate monosaccharide and polysaccharide; (3) Nanofiltration membrane can effectively retain [Amim] Cl in spinning wastewater. The surface electrokinetics of nanofiltration membrane was studied by flow potential method. The effects of concentration and pressure on the surface Zeta potential and charge density were studied. The results showed that both the absolute value of the surface flow potential (ΔE) and the surface zeta potential (ζ) of the nanofiltration membrane decreased with the increase of electrolyte concentration and pressure. The order of ΔE in different electrolyte solutions was NaCl> MgCl2> KCl> KBr> Na2SO4> MgSO4. The absolute value of surface charge density (σd) increases with the increase of electrolyte concentration and decreases with the increase of pressure. The relationship between the structure of the functional layer and the entrapment performance of the nanofiltration membrane was studied by flow potential method. Experiments show that the flow potential method can be used to study the entrapment mechanism of the composite nanofiltration membrane and the functional layer structure. The potential parameters such as flow potential (ΔE), zeta potential (ζ) and surface charge density (σd) can be obtained by the flow potential method. The changes of these parameters are consistent with those of the functional layer and the rejection of the nanofiltration membrane. The ξ of composite nanofiltration membrane increased according to Na2SO4> MgSO4> MgCl2, which was consistent with the change of rejection. The absolute value of the surface electrical performance parameters of the nanofiltration membrane obtained after the crosslinking with the pendant monomer is smaller than that without the pendant monomer.