高分离精度抗污染PVDF中空纤维膜的制备
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摘要
聚偏氟乙烯(PVDF)是一种常见的高分子膜材料,具有优良的机械强度、热稳定性和耐化学性,在水处理领域获得了广泛的应用.但由于PVDF膜表面润湿性差,在处理含有机物的废水时易被污染;同时孔径较大的PVDF膜在应用方面会受到一定的限制.为了有效减少膜污染并达到调控孔径的目的,本文采用亲水聚合物聚乙烯醇(PVA)通过表面涂覆、窄缝刮涂、交联的方法对PVDF膜进行改性,改性后的PVDF膜截留分子量减小到80 000以下.当PVA涂覆浓度为1.0%(质量分数)时,改性膜的亲水性能显著提高,在葡聚糖溶液过滤实验中,改性膜的通量几乎不衰减,保持高抗污染性能.
Poly(vinylidene fluoride)(PVDF) is a common polymer membrane material, which has excellent mechanical strength, thermal stability and chemical resistance, and it has been widely applied in the field of water treatment. However, PVDF membranes are vulnerable to be fouled in the treatment of wastewater containing organics matters due to their poor surface wettability, and for membranes with large pore size, their real application is limited. In this study, in order to effectively reduce membrane fouling and achieve the purpose of regulating the membrane pore size, PVDF membranes were modified by surface coating, slit scraping and cross-linking to improve PVDF membrane fouling resistance and separation performance using a hydrophilic substance-polyvinyl alcohol(PVA). The molecular weight cuts-off of the modified PVDF membrane was reduced to less than 80 000. When the PVA coating concentration was 1.0%(mass fraction), the hydrophilicity of the modified membrane was significantly increased. In the dextran solution filtration experiment, the flux of the modified membrane was remained stable and maintained a relatively high anti-fouling performance.
Poly(vinylidene fluoride)(PVDF) is a common polymer membrane material, which has excellent mechanical strength, thermal stability and chemical resistance, and it has been widely applied in the field of water treatment. However, PVDF membranes are vulnerable to be fouled in the treatment of wastewater containing organics matters due to their poor surface wettability, and for membranes with large pore size, their real application is limited. In this study, in order to effectively reduce membrane fouling and achieve the purpose of regulating the membrane pore size, PVDF membranes were modified by surface coating, slit scraping and cross-linking to improve PVDF membrane fouling resistance and separation performance using a hydrophilic substance-polyvinyl alcohol(PVA). The molecular weight cuts-off of the modified PVDF membrane was reduced to less than 80 000. When the PVA coating concentration was 1.0%(mass fraction), the hydrophilicity of the modified membrane was significantly increased. In the dextran solution filtration experiment, the flux of the modified membrane was remained stable and maintained a relatively high anti-fouling performance.
引文
[1] Jesswein I,Hirth T,Schiestel T.Continuous dip coating of PVDF hollow fiber membranes with PVA for humidification[J].J Membr Sci,2017,541:281-290.
[2] Sina B,Shung C T,Raj R.A novel approach to fabricate macrovoid-free and highly permeable PVDF hollow fiber membranes for membrane distillation[J].AIChE J,2010,55(3):828-833.
[3] Cui Z,Cheng Y,Xu K,et al.Wide liquid-liquid phase separation region enhancing tensile strength of poly(vinylidene fluoride) membranes via TIPS method with a new diluent[J].Polymer,2018,141:46-53.
[4] Hu Y,Lu K,Yan F,et al.Enhancing the performance of aromatic polyamide reverse osmosis membrane by surface modification via covalent attachment of polyvinyl alcohol (PVA)[J].J Membr Sci,2016,501:209-219.
[5] Wang X,Fang D,Yoon K,et al.High performance ultrafiltration composite membranes based on poly(vinyl alcohol) hydrogel coating on crosslinked nanofibrous poly(vinyl alcohol) scaffold[J].J Membr Sci,2006,278(1):261-268.
[6] He Z,Miller D J,Kasemset S,et al.Fouling propensity of a poly(vinylidene fluoride) microfiltration membrane to several model oil/water emulsions[J].J Membr Sci,2016,514:659-670.
[7] Kang G D,Cao Y M.Application and modification of poly(vinylidene fluoride) (PVDF) membranes-A review [J].J Membr Sci,2014,463(1):145-165.
[8] Li N,Xiao C,An S,et al.Preparation and properties of PVDF/PVA hollow fiber membranes [J].Desalination,2010,250(2):530-537.
[9] Li L,Hou J,Ye Y,et al.Composite PVA/PVDF pervaporation membrane for concentrated brine desalination:Salt rejection,membrane fouling and defect control [J].Desalination,2017,422:49-58.
[10] Jesswein I,Hirth T,Schiestel T.Continuous dip coating of PVDF hollow fiber membranes with PVA for humidification [J].J Membr Sci,2017,541:281-290.
[11] Liu L,Zhao C,Yang F.TiO2 and polyvinyl alcohol (PVA) coated polyester filter in bioreactor for wastewater treatment [J].Water Res,2012,46(6):1969-1978.
[12] Zeng K,Zhou J,Cui Z,et al.Insight into fouling behavior of poly(vinylidene fluoride)(PVDF) hollow fiber membranes caused by dextran with different pore size distributions [J].Chin J Chem Eng,2018,26(2):268-277.
[13] 曾凯亮,汪朝晖,崔朝亮,等.超滤膜在处理农药废水过程中的膜污染行为分析 [J].膜科学与技术,2018,38(2):98-105.
[14] Du J R,Peldszus S,Huck P M,et al.Modification of poly(vinylidene fluoride) ultrafiltration membranes with poly(vinyl alcohol) for fouling control in drinking water treatment [J].Water Res,2009,43(18):4559-4568.
[15] Jin T,Zhao Z,Chen K.Preparation of a poly(vinyl chloride) ultrafiltration membrane through the combination of thermally induced phase separation and non-solvent-induced phase separation[J].J Appl Polym Sci,2015,133(5):1-12.
[2] Sina B,Shung C T,Raj R.A novel approach to fabricate macrovoid-free and highly permeable PVDF hollow fiber membranes for membrane distillation[J].AIChE J,2010,55(3):828-833.
[3] Cui Z,Cheng Y,Xu K,et al.Wide liquid-liquid phase separation region enhancing tensile strength of poly(vinylidene fluoride) membranes via TIPS method with a new diluent[J].Polymer,2018,141:46-53.
[4] Hu Y,Lu K,Yan F,et al.Enhancing the performance of aromatic polyamide reverse osmosis membrane by surface modification via covalent attachment of polyvinyl alcohol (PVA)[J].J Membr Sci,2016,501:209-219.
[5] Wang X,Fang D,Yoon K,et al.High performance ultrafiltration composite membranes based on poly(vinyl alcohol) hydrogel coating on crosslinked nanofibrous poly(vinyl alcohol) scaffold[J].J Membr Sci,2006,278(1):261-268.
[6] He Z,Miller D J,Kasemset S,et al.Fouling propensity of a poly(vinylidene fluoride) microfiltration membrane to several model oil/water emulsions[J].J Membr Sci,2016,514:659-670.
[7] Kang G D,Cao Y M.Application and modification of poly(vinylidene fluoride) (PVDF) membranes-A review [J].J Membr Sci,2014,463(1):145-165.
[8] Li N,Xiao C,An S,et al.Preparation and properties of PVDF/PVA hollow fiber membranes [J].Desalination,2010,250(2):530-537.
[9] Li L,Hou J,Ye Y,et al.Composite PVA/PVDF pervaporation membrane for concentrated brine desalination:Salt rejection,membrane fouling and defect control [J].Desalination,2017,422:49-58.
[10] Jesswein I,Hirth T,Schiestel T.Continuous dip coating of PVDF hollow fiber membranes with PVA for humidification [J].J Membr Sci,2017,541:281-290.
[11] Liu L,Zhao C,Yang F.TiO2 and polyvinyl alcohol (PVA) coated polyester filter in bioreactor for wastewater treatment [J].Water Res,2012,46(6):1969-1978.
[12] Zeng K,Zhou J,Cui Z,et al.Insight into fouling behavior of poly(vinylidene fluoride)(PVDF) hollow fiber membranes caused by dextran with different pore size distributions [J].Chin J Chem Eng,2018,26(2):268-277.
[13] 曾凯亮,汪朝晖,崔朝亮,等.超滤膜在处理农药废水过程中的膜污染行为分析 [J].膜科学与技术,2018,38(2):98-105.
[14] Du J R,Peldszus S,Huck P M,et al.Modification of poly(vinylidene fluoride) ultrafiltration membranes with poly(vinyl alcohol) for fouling control in drinking water treatment [J].Water Res,2009,43(18):4559-4568.
[15] Jin T,Zhao Z,Chen K.Preparation of a poly(vinyl chloride) ultrafiltration membrane through the combination of thermally induced phase separation and non-solvent-induced phase separation[J].J Appl Polym Sci,2015,133(5):1-12.