聚全氟乙丙烯中空纤维复合膜的制备及其染料/无机盐分离性能研究

doi:10.11949/0438-1157.20240800

摘要/Abstract

摘要：

利用膜分离技术进行染料脱盐，对实现纺织印染废水的清洁处理与资源回收具有重要意义。以聚全氟乙丙烯（FEP）中空纤维膜为基膜，通过邻苯二酚（CA）和聚乙烯亚胺（PEI）共沉积改善膜表面亲水性，利用聚吡咯（PPy）构筑中间层优化界面聚合过程，制备FEP中空纤维复合膜。结果表明：改性后，膜表面的水接触角由122°降至39°，亲水性改善；当吡咯（Py）浓度为10%（质量分数）时，所得复合膜综合性能最佳，对考马斯亮蓝和刚果红等的截留率达95%、NaCl和MgSO₄等的截留率均低于8%，可实现染料与无机盐的高效分离。经有机溶剂处理以及在高运行温度（80℃）下，膜的截留率保持稳定，显示耐热和耐溶剂性良好。此外，FEP中空纤维复合膜还可实现二元染料分离。

关键词: 聚全氟乙丙烯, 膜, 结构设计, 分离, 废水

Abstract:

The use of membrane separation technology for dye desalination is of great significance for the clean treatment and resource recovery of textile printing and dyeing wastewater. In this paper, poly(tetrafluoroethylene-co-hexafluoropropylene) (FEP) hollow fiber porous membrane prepared by melt spinning was utilized as the base membrane. The surface hydrophilicity of FEP hollow fiber composite membrane was improved by co-deposition of catechol (CA) and polyethylenimine (PEI) on the membrane surface, and the interfacial polymerization process was optimized by polypyrrole (PPy) as the intermediate layer. Finally, the FEP hollow fiber composite membrane was fabricated. The results showed that the water contact angle of the membrane was reduced from 122° to 39° after modification, and the hydrophilicity was improved. When the concentration of pyrrole was 10%(mass fraction), the composite membrane had the best comprehensive performance. The rejection of dyes such as Coomath brilliant blue and Congo red were above 95%, while the rejection of salts such as NaCl and MgSO₄were all below 8%, which could realize the efficient separation of dyes and inorganic salts. Furthermore, when the FEP hollow fiber composite membrane was tested at 80℃ and treated with organic solvent, the dye rejection remained stable, indicating excellent resistance to heat and solvents. In addition, FEP hollow fiber composite membrane was capable of achieving the separation of binary dyes.

Key words: FEP, membrane, structure design, separation, waste water

中图分类号:

TQ 028.8

王璐遥, 张广勇, 于海鑫, 张轩诚, 黄岩, 赵玉潮. 聚全氟乙丙烯中空纤维复合膜的制备及其染料/无机盐分离性能研究[J]. 化工学报, 2024, 75(11): 4309-4319.

Luyao WANG, Guangyong ZHANG, Haixin YU, Xuancheng ZHANG, Yan HUANG, Yuchao ZHAO. Preparation of poly(tetrafluoroethylene-co-hexafluoropropylene) hollow fiber composite membrane for dye/inorganic salt separation[J]. CIESC Journal, 2024, 75(11): 4309-4319.

图/表 17

图1 FEP中空纤维多孔基膜制备及成孔过程

Fig.1 Schematic diagram of the preparation and pore-forming process of FEP hollow fiber porous base membrane

图2 FEP中空纤维复合膜制备过程示意图

Fig.2 Schematic diagram of the preparation process of FEP hollow fiber composite membrane

表1 膜标号与膜名称

Table 1 Membrane code and membrane name

膜标号	膜名称
M1	FEP中空纤维膜
M2	亲水改性后的FEP中空纤维膜
M3	构筑中间层后的FEP中空纤维膜
M4	FEP中空纤维复合膜
M4-6	6%（质量分数）Py制备的FEP中空纤维复合膜
M4-8	8%（质量分数）Py制备的FEP中空纤维复合膜
M4-10	10%（质量分数）Py制备的FEP中空纤维复合膜
M4-12	12%（质量分数）Py制备的FEP中空纤维复合膜

图3 FEP中空纤维复合膜纯水通量与分离性能测试装置

Fig.3 Testing device for pure water flux and separation performance of FEP hollow fiber composite membrane

图4 FEP中空纤维多孔基膜形貌

Fig.4 Morphology of FEP hollow fiber porous base membrane

图5 M2、M3、M4膜形貌结构

Fig.5 Morphology and structure of M2, M3, and M4

图6 不同膜样品FTIR谱图

Fig.6 FTIR spectra of different membrane samples

图7 不同膜样品的水接触角

Fig.7 Water contact angle of different membrane samples

图8 不同膜样品应力应变曲线

Fig.8 Stress-strain curves of different membrane samples

图9 FEP中空纤维复合膜纯水通量

Fig.9 Pure water flux of FEP hollow fiber composite membrane

图10 FEP中空纤维复合膜Zeta电位

Fig.10 Zeta potential of the FEP hollow fiber composite membrane

图11 Py浓度对所得中空纤维复合膜分离性能影响

Fig.11 Effect of Py concentration on separation performance of hollow fiber composite membrane

图12 FEP中空纤维复合膜染料脱盐性能

Fig.12 Dye desalination performance of the FEP hollow fiber composite membrane

图13 FEP中空纤维复合膜结构设计示意图

Fig.13 Schematic diagram of the structure design for FEP hollow fiber composite membrane

图14 FEP中空纤维复合膜对二元染料混合物的分离性能

Fig.14 Separation performance of FEP hollow fiber composite membrane for binary dye mixtures

图15 FEP中空纤维复合膜耐温和耐溶剂性能

Fig.15 Thermal stability and solvent resistance of FEP hollow fiber composite membrane

表2 本研究与文献报道的中空纤维复合膜染料/盐分离性能比较

Table 2 Separation performance comparison of hollow fiber composite membrane in this work with literatures

膜材料	渗透通量	操作压力	染料截留率	盐截留率	文献
PP中空纤维复合膜	5.8 L/(m²· h)	0.07 MPa	99.6%（BG，1000 mg/L）	5%（NaCl，1000 mg/L）	[25]
PP中空纤维复合膜	5.6 L/(m²· h)	0.08 MPa	99.8%（CR，2000 mg/L）	<2%（NaCl，10000 mg/L）	[26]
PVDF中空纤维复合膜	20.4 L/(m²· h)	0.2 MPa	99.99%（CR，50 mg/L）	6.2%（NaCl，1000 mg/L）	[27]
PVDF中空纤维复合膜	约9 L/(m²· h)	0.1 MPa	98.5%（AO10，50 mg/L）	约4%（NaCl，1000 mg/L）	[28]
PAN中空纤维复合膜	43.5 L/(m²· h)	0.3 MPa	>99%（CR，50 mg/L）	约10%（NaCl，1000 mg/L）	[29]
PPTA中空纤维复合膜	28.6 L/(m²· h)	0.6 MPa	99.9%（CR，100 mg/L）	22.4%（NaCl，1000 mg/L）	[30]
FEP中空纤维复合膜	2.45 kg/(m²· h)（20℃） 7.12 kg/(m²· h)（80℃）	0.5 MPa	99.1%（CBB，100 mg/L） 99.1%（CBB，100 mg/L）	7.5%（NaCl，1000 mg/L） 7.1%（MgSO₄，1000 mg/L）	本文

参考文献 30

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