聚醚砜纳滤膜的制备、结构调控与性能研究
发布时间：2019-01-03 14:49
【摘要】：本文采用相转化法制备了磺化聚砜(SPSF)/聚醚砜(PES)/苯乙烯-马来酸酐共聚物(SMA)共混新型纳滤膜,以磺化聚砜(SPSF)和聚醚砜(PES)作为制备基膜的原材料,以聚乙烯吡咯烷酮(PVP)和苯乙烯-马来酸酐共聚物(SMA)作为添加剂,以N,N-二甲基乙酰胺(DMAc)作为溶剂,通过研究不同的SPSF与PES固含量值,不同的PVP添加量,不同的SMA添加量来探讨这些物质配比对膜结构性能的影响;同时还讨论了制膜工艺条件中的预蒸发时间,预蒸发温度,凝固浴温度和铸膜液温度对SPSF/PES/SMA共混纳滤基膜结构性能的影响;为进一步对制备的膜进行优化改性,最后对膜表面进行改性处理,其中以甲醛为交联剂,使其与马来酸酐(MA)官能团发生交联反应形成纳滤脱盐层,考察了交联剂浓度、交联温度、交联时间对脱盐层结构和脱盐率的影响规律,并初步解释了纳滤脱盐层的形成过程。研究结果表明,随着SPSF与PES固含量的增加,膜水通量整体上呈现递减趋势,膜对Na2SO4的脱盐率上升。随着PVP含量的增加,铸膜液粘度变大,膜指状孔得到抑制。随着SMA的加入消除了膜的指状孔,使膜内部结构变得致密。当选取SPSF与PES固含量为25%、添加剂PVP固含量为5%、添加剂SMA固含量为6%时制备出的SPSF/PES/SMA共混纳滤基膜综合性能较好。在SPSF/PES/SMA体系中,随着预蒸发时间增加,水通量下降,脱盐率上升。固定其它条件不变,随着预蒸发温度的升高,膜水通量降低,脱盐率上升。随着凝固浴温度升高,膜水通量上升,且在此过程中膜对Na2SO4的截留率上升。最后考察铸膜液溶解温度对膜性能的影响,随着铸膜液温度的上升,膜水通量先升后降,脱盐率则是先降后升。综合考虑预蒸发时间为90s,预蒸发温度为70℃,凝固浴温度为25℃,铸膜液温度为60℃时为最优制膜工艺条件,此时的膜对二价盐Na2SO4的截留率为56.70%,水通量为39.96L/m~2·h。为进一步对制备的膜进行优化改性,最后对膜表面进行改性处理。随着交联剂浓度从4%增加到12%,膜对Na2SO4的截留率从57.84%提高到75.89%,总体上对比基膜56.70%的脱盐率,改性过后的膜明显优于基膜。固定其他条件不变,升高交联温度不利于得到高水通量的膜。此外随着交联时间增加,膜皮层厚度增加,膜水通量下降。综合考虑,当交联条件中交联剂浓度为10%,交联温度为90℃,交联时间为3h时改性的膜综合性能较优,此时测得的脱盐率为77.25%,对应的水通量也能达到13.75L/m~2·h。
[Abstract]:A novel sulfonated polysulfone (SPSF) / polyethersulfone (PES) / styrene-maleic anhydride copolymer (SMA) nanofiltration membrane was prepared by phase inversion method. Sulfonated polysulfone (SPSF) and polyethersulfone (PES) were used as the raw materials for the preparation of the membranes. Polyvinylpyrrolidone (PVP) and styrene-maleic anhydride copolymer (SMA) were used as additives and NN-dimethyl acetamide (DMAc) as solvent. The solid contents of SPSF and PES were studied. The effects of different SMA ratios on the structure and properties of the membranes were investigated. At the same time, the effects of pre-evaporation time, pre-evaporation temperature, coagulation bath temperature and casting liquid temperature on the structure and properties of SPSF/PES/SMA blend nanofiltration membrane were also discussed. In order to optimize the membrane, the surface of the membrane was modified. Formaldehyde was used as crosslinking agent to form a nanofiltration desalination layer with maleic anhydride (MA) functional group. The concentration of crosslinking agent was investigated. The effects of crosslinking temperature and crosslinking time on the structure and desalination rate of desalination layer were studied. The formation process of nanofiltration desalination layer was also explained. The results show that with the increase of solid content of SPSF and PES, the water flux of the membrane decreases as a whole, and the desalination rate of the membrane to Na2SO4 increases. With the increase of PVP content, the viscosity of casting solution increased and the finger pore was inhibited. With the addition of SMA, the finger-like pores of the membrane were eliminated, and the internal structure of the membrane became compact. When the solid content of SPSF and PES is 25, the solid content of additive PVP is 5 and the solid content of additive SMA is 6, the composite properties of SPSF/PES/SMA blend nanofiltration base membrane are better. In SPSF/PES/SMA system, with the increase of pre-evaporation time, the water flux decreases and the desalinization rate increases. With the increase of preevaporation temperature, the membrane water flux decreases and the desalinization rate increases. With the increase of coagulation bath temperature, the water flux of the membrane increased, and the rejection rate of membrane to Na2SO4 increased during the process. Finally, the effect of solution temperature on membrane properties was investigated. With the increase of casting temperature, the membrane water flux increased first and then decreased, and the desalinization rate decreased first and then increased. When the pre-evaporation time is 90 s, the pre-evaporation temperature is 70 鈩，
本文编号：2399532
[Abstract]:A novel sulfonated polysulfone (SPSF) / polyethersulfone (PES) / styrene-maleic anhydride copolymer (SMA) nanofiltration membrane was prepared by phase inversion method. Sulfonated polysulfone (SPSF) and polyethersulfone (PES) were used as the raw materials for the preparation of the membranes. Polyvinylpyrrolidone (PVP) and styrene-maleic anhydride copolymer (SMA) were used as additives and NN-dimethyl acetamide (DMAc) as solvent. The solid contents of SPSF and PES were studied. The effects of different SMA ratios on the structure and properties of the membranes were investigated. At the same time, the effects of pre-evaporation time, pre-evaporation temperature, coagulation bath temperature and casting liquid temperature on the structure and properties of SPSF/PES/SMA blend nanofiltration membrane were also discussed. In order to optimize the membrane, the surface of the membrane was modified. Formaldehyde was used as crosslinking agent to form a nanofiltration desalination layer with maleic anhydride (MA) functional group. The concentration of crosslinking agent was investigated. The effects of crosslinking temperature and crosslinking time on the structure and desalination rate of desalination layer were studied. The formation process of nanofiltration desalination layer was also explained. The results show that with the increase of solid content of SPSF and PES, the water flux of the membrane decreases as a whole, and the desalination rate of the membrane to Na2SO4 increases. With the increase of PVP content, the viscosity of casting solution increased and the finger pore was inhibited. With the addition of SMA, the finger-like pores of the membrane were eliminated, and the internal structure of the membrane became compact. When the solid content of SPSF and PES is 25, the solid content of additive PVP is 5 and the solid content of additive SMA is 6, the composite properties of SPSF/PES/SMA blend nanofiltration base membrane are better. In SPSF/PES/SMA system, with the increase of pre-evaporation time, the water flux decreases and the desalinization rate increases. With the increase of preevaporation temperature, the membrane water flux decreases and the desalinization rate increases. With the increase of coagulation bath temperature, the water flux of the membrane increased, and the rejection rate of membrane to Na2SO4 increased during the process. Finally, the effect of solution temperature on membrane properties was investigated. With the increase of casting temperature, the membrane water flux increased first and then decreased, and the desalinization rate decreased first and then increased. When the pre-evaporation time is 90 s, the pre-evaporation temperature is 70 鈩，
本文编号：2399532
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