抗污染聚醚砜超滤膜的制备及其在油水分离中的应用
发布时间：2018-12-11 17:25
【摘要】：随着现代工业的快速发展,水环境问题越来越受到人们的重视,尤其是工业有机废水、含油污水的处理问题备受关注。各种水处理方法、工艺在水质调理过程中得到了广泛应用,而膜分离技术被认为是解决水质问题工艺环节中的重要措施之一。高分子聚合物聚醚砜(PES)具有耐高温、强度高、物化性质稳定等优点,是理想的膜材料。但在实际使用中,由于PES本身的疏水性,纯PES膜易被污染,导致膜的分离效率下降,操作成本增加,限制其工业应用。本文采用物理共混和化学接枝并用的方法对疏水性PES膜进行两步亲水化改性,来提高其抗污染性能,增强其实际应用性。文中先采用物理共混法对PES膜进行亲水化改性。利用表面引发的可逆加成断裂链转移聚合法(RAFT),以普兰尼克F-127(F127)和丙烯酸(AA)为原料,合成亲水性嵌段聚合物PAA-F127-PAA,将其作为添加剂以不同比例与PES共混,通过非溶剂致相分离法(NIPS)制备PES/PAA-F127-PAA膜。研究表明,在成膜过程中,亲水性的PAA-F127-PAA会在界面自由能最低化驱使下自发地向膜表面迁移,膜的纯水通量、亲水性、抗污染能力都得到了改善。且随添加剂含量的增加,纯水通量表现为先增大后减小的趋势。当添加剂相对PES的添加量为5wt%时,膜的性能最好,与纯PES膜相比,纯水通量从122.11L/(m2·h)增大到333.72L/(m2.h),接触角从82.6°减小到64.3°,通量恢复率从45.75%提高到81.34%。此外,为继续提升改性膜的性能,在物理共混改性基础上对膜进行进一步化学接枝亲水化改性。通过控制电子转移活化再生催化剂原子转移自由基聚合法(ARGET ATRP)的聚合时间,由(2-乙基(2-溴-2-甲基丙酰氨基))叔丁基氨基甲酸(Boc-Br)和甲基丙烯酸二甲氨乙酯(DMAEMA),合成了不同链长的强亲水性聚合物NH2-PDMAPS。以上述性能最好的共混改性膜为基膜,利用合成的亲水性聚合物NH2-PDMAPS与膜表面PAA链段进行酰胺化反应,制备了PES/PAA-F127-PAA/NH2-PDMAPS改性膜。实验表明,随着膜表面接枝的NH2-PDMAPS链长的增加,膜的纯水通量先增大后减小。当聚合时间为8h时,改性膜的性能最佳,纯水通量为280.78L/(m2·h),接触角为45.3°,通量恢复率高达93.45%,相比于纯PES膜,纯水通量增大了 129.9%,接触角降低了 47.1%,通量恢复率提高了 106.6%。膜的抗污染能力得到了显著提升,油水分离效果得到了明显增强。
[Abstract]:With the rapid development of modern industry, people pay more and more attention to the problem of water environment, especially the treatment of industrial organic wastewater and oily wastewater. Various water treatment methods have been widely used in the process of water quality conditioning, and membrane separation technology is considered as one of the most important measures to solve water quality problems. Polymer polyethersulfone (PES) is an ideal membrane material because of its high temperature resistance, high strength and stable physicochemical properties. However, due to the hydrophobicity of PES, the membrane of pure PES is liable to be contaminated, which leads to the decrease of membrane separation efficiency and the increase of operation cost, which limits its industrial application. In this paper, the hydrophilic modification of hydrophobic PES membrane was carried out by means of physical blending and chemical grafting in order to improve its anti-pollution performance and enhance its practical application. In this paper, the hydrophilic modification of PES membrane was carried out by physical blending method. The hydrophilic block polymer PAA-F127-PAA, was synthesized by surface-initiated reversible addition-breaking chain transfer polymerization (RAFT),) with (AA) and F-127 (F127) as raw materials. The PES/PAA-F127-PAA membrane was prepared by non-solvent induced phase separation (NIPS) method by blending it with PES in different proportion as additive. The results show that the hydrophilic PAA-F127-PAA can migrate spontaneously to the membrane surface under the lowest free energy at the interface. The pure water flux, hydrophilicity and antifouling ability of the membrane are improved. With the increase of additive content, the pure water flux increased first and then decreased. When the content of additive relative to PES is 5 wt%, the performance of the membrane is the best. Compared with the pure PES membrane, the pure water flux increases from 122.11L/ (m 2 h) to 333.72L/ (m 2 h), and the contact angle decreases from 82.6 掳to 64.3 掳. The flux recovery rate increased from 45.75% to 81.34%. In addition, in order to improve the properties of the modified membrane, further chemical grafted hydrophilic modification was carried out on the basis of physical blending modification. The polymerization time of (ARGET ATRP) by atom transfer radical polymerization with electron transfer activated regeneration catalyst was controlled. A strong hydrophilic polymer NH2-PDMAPS. with different chain lengths was synthesized from (2-ethyl (2-bromo-2-methylpropionyl) tert-Ding Ji carbamate (Boc-Br) and dimethylaminoethyl methacrylate (DMAEMA),). The PES/PAA-F127-PAA/NH2-PDMAPS modified membrane was prepared by amidation of the hydrophilic polymer NH2-PDMAPS with the PAA segment of the membrane surface. The experimental results show that the pure water flux of the membrane increases first and then decreases with the increase of the NH2-PDMAPS chain length on the surface of the membrane. When the polymerization time is 8 h, the performance of the modified membrane is the best. The pure water flux is 280.78L/ (m ~ 2 h), contact angle is 45.3 掳, and the flux recovery rate is 93.45 掳). Compared with the pure PES membrane, the pure water flux increases 129.9%. The contact angle decreased by 47.1 and the flux recovery rate increased by 106.6. The antifouling ability of the membrane was improved significantly, and the separation effect of oil and water was obviously enhanced.
【学位授予单位】：东南大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ051.893;X703
本文编号：2372939
[Abstract]:With the rapid development of modern industry, people pay more and more attention to the problem of water environment, especially the treatment of industrial organic wastewater and oily wastewater. Various water treatment methods have been widely used in the process of water quality conditioning, and membrane separation technology is considered as one of the most important measures to solve water quality problems. Polymer polyethersulfone (PES) is an ideal membrane material because of its high temperature resistance, high strength and stable physicochemical properties. However, due to the hydrophobicity of PES, the membrane of pure PES is liable to be contaminated, which leads to the decrease of membrane separation efficiency and the increase of operation cost, which limits its industrial application. In this paper, the hydrophilic modification of hydrophobic PES membrane was carried out by means of physical blending and chemical grafting in order to improve its anti-pollution performance and enhance its practical application. In this paper, the hydrophilic modification of PES membrane was carried out by physical blending method. The hydrophilic block polymer PAA-F127-PAA, was synthesized by surface-initiated reversible addition-breaking chain transfer polymerization (RAFT),) with (AA) and F-127 (F127) as raw materials. The PES/PAA-F127-PAA membrane was prepared by non-solvent induced phase separation (NIPS) method by blending it with PES in different proportion as additive. The results show that the hydrophilic PAA-F127-PAA can migrate spontaneously to the membrane surface under the lowest free energy at the interface. The pure water flux, hydrophilicity and antifouling ability of the membrane are improved. With the increase of additive content, the pure water flux increased first and then decreased. When the content of additive relative to PES is 5 wt%, the performance of the membrane is the best. Compared with the pure PES membrane, the pure water flux increases from 122.11L/ (m 2 h) to 333.72L/ (m 2 h), and the contact angle decreases from 82.6 掳to 64.3 掳. The flux recovery rate increased from 45.75% to 81.34%. In addition, in order to improve the properties of the modified membrane, further chemical grafted hydrophilic modification was carried out on the basis of physical blending modification. The polymerization time of (ARGET ATRP) by atom transfer radical polymerization with electron transfer activated regeneration catalyst was controlled. A strong hydrophilic polymer NH2-PDMAPS. with different chain lengths was synthesized from (2-ethyl (2-bromo-2-methylpropionyl) tert-Ding Ji carbamate (Boc-Br) and dimethylaminoethyl methacrylate (DMAEMA),). The PES/PAA-F127-PAA/NH2-PDMAPS modified membrane was prepared by amidation of the hydrophilic polymer NH2-PDMAPS with the PAA segment of the membrane surface. The experimental results show that the pure water flux of the membrane increases first and then decreases with the increase of the NH2-PDMAPS chain length on the surface of the membrane. When the polymerization time is 8 h, the performance of the modified membrane is the best. The pure water flux is 280.78L/ (m ~ 2 h), contact angle is 45.3 掳, and the flux recovery rate is 93.45 掳). Compared with the pure PES membrane, the pure water flux increases 129.9%. The contact angle decreased by 47.1 and the flux recovery rate increased by 106.6. The antifouling ability of the membrane was improved significantly, and the separation effect of oil and water was obviously enhanced.
【学位授予单位】：东南大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ051.893;X703
【参考文献】
相关期刊论文 前1条
1 唐龙祥;范保林;刘春华;张奎;王平华;;ATRP法在纳米SiO_2表面接枝PS及其对HDPE的改性[J];高分子材料科学与工程;2011年05期
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