含碳纳米管TFN膜的制备与性能测试

发布时间：2018-06-27 23:33

本文选题：正渗透 + 纳滤　；参考：《中国海洋大学》2015年硕士论文

【摘要】：本文用界面聚合法制备出新型高性能含碳纳米管的复合正渗透膜。并探索了制备多孔支撑层和表面分离层的工艺条件,得出了最佳制膜条件。将碳纳米管添加到多孔支撑层和表面分离层中,探究了复合膜中碳纳米管的含量和管径对膜的渗透性能和结构的影响。此外,还对膜的正渗透,纳滤性能和抗污能力进行了测试,并得出以下主要结论：膜的水通量随着基膜铸膜液中致孔剂的含量的增加而提高,异丙醇溶胀也可提高膜通量,但提高不太明显,通量不超过1.0 L/(m2h)。表面分离层的制备条件的探究最终确定膜的制备条件为：致孔剂含量8 g,界面聚合反应时间为30 s,界面聚合水相反应单体浓度为0.5%,油相单体浓度为0.1%。多巴胺改性浓度为2g/L,改性时间24 h。改性膜获得了4.05 L/(m2h)的通量,而反混通量相对于改性基底明显下降,Js/J,约为0.13g/L。复合膜的水通量随着改性层中碳纳米管含量的增加先增大后减小。当改性层中碳纳米管添加量为0.05%时,膜获得最大正渗透通量,水通量由原膜的2.30L/(m2h)上升到4.92 L/(m2h),对NaCl的截留率保持在90%。对于氯化镁/纯水体系,复合膜获得最大水通量为7.24 L/(m2h), Js/Jv约为0.42g/L。多壁碳纳米管比单壁管使复合膜更高地提高膜的水通量,并获得更低的反混通量。此外,当支撑层中碳纳米管添加含量为0.15%时,膜获得氯化镁/纯水体系最大通量为7.15L/(m2h)：当支撑层和改性层中都添加碳纳米管时,复合膜获得最大水通量为8.25L/(m2h),Js/Jv约为0.03g/L。与纯聚酰胺膜相比,在支撑层和改性层中都添加碳纳米管的复合正渗透膜能获得更高的水通量,同时保持其截留率。在4 bar操作压力下,基膜添加0.15%、改性层添加0.05%的复合膜水通量为29.33 L/(m2h),对200 ppm MgCl2的截留率为40%,而纯聚酰胺膜的水通量为20.89 L/(m2h),截留率为41%。所制备的正渗透复合膜抗污能力明显高于纯聚酰胺膜,3次污染-清洗-恢复循环后,改性层中添加量为0.05%的复合膜正渗透的水通量恢复率为80.1%,纳滤通量恢复率为51.5%,而纯聚酰胺膜的分别为73.4%和35.9%。
[Abstract]:In this paper, a novel high performance carbon nanotube composite percolation membrane was prepared by interfacial polymerization. The preparation conditions of porous supporting layer and surface separation layer were investigated and the optimum conditions of membrane preparation were obtained. Carbon nanotubes (CNTs) were added to porous support layer and surface separation layer to investigate the effect of the content and diameter of CNTs on the permeability and structure of the membrane. In addition, the direct permeation, nanofiltration and antifouling properties of the membrane were tested. The main conclusions were as follows: the water flux of the membrane increased with the increase of the content of pore-forming agent in the casting solution of the base membrane, and the flux of the membrane was also increased by the swelling of isopropanol. But the increase was not obvious and the flux was not more than 1.0 L / (m2h). The preparation conditions of the surface separation layer are as follows: the content of pore-forming agent is 8 g, the reaction time is 30 s, the monomer concentration of aqueous phase is 0.5 and the concentration of oil monomer is 0.1. The modified concentration of dopamine was 2 g / L and the modification time was 24 h. The flux of modified membrane was 4.05 L / (m2h), while the flux of reverse mixing decreased significantly compared with the modified substrate, about 0.13 g / L. The water flux of the composite membrane increased firstly and then decreased with the increase of carbon nanotube content in the modified layer. When the amount of carbon nanotubes added in the modified layer was 0.05, the maximum positive osmotic flux was obtained, the water flux increased from 2.30L / (m2h) of the original membrane to 4.92L / (m2h), and the retention rate of NaCl was kept at 90L / (m2h). For magnesium chloride / pure water system, the maximum water flux of the composite membrane is 7.24 L / (m2h), and the Js / Jv is about 0.42 g / L. Compared with single-walled carbon nanotubes, multiwalled carbon nanotubes (MWNTs) increase the water flux and obtain lower reverse fluxes. In addition, when the carbon nanotube content in the supporting layer is 0.15, the maximum flux of magnesium chloride / pure water system is 7.15L / (m2h). When carbon nanotubes are added to the supporting layer and modified layer, the maximum water flux of the composite membrane is 8.25L / (m2h) / (m2h) Js-Jv is about 0.03g/ L. Compared with the pure polyamide membrane, the composite forward permeable membrane with carbon nanotubes added in the supporting layer and the modified layer can obtain higher water flux while maintaining its retention rate. Under the operating pressure of 4 bar, the water flux of the composite membrane was 29.33L / (m2h) and the water flux of the pure polyamide membrane was 20.89L / (m2h), and the water flux of the pure polyamide membrane was 20.89L / (m2h). The water flux of the modified membrane was 29.33L / (m2h), and the rejection rate of the modified membrane was 41L / (m2h), while the water flux of the pure polyamide membrane was 20.89L / (m2h). The antifouling ability of the composite membrane was obviously higher than that of the pure polyamide membrane after three fouling, cleaning and recovery cycles. The recovery rate of water flux and nanofiltration flux was 80.1% and 51.5% respectively for the composite membrane with 0.05% addition in the modified layer, and 73.4% and 35.9% for the pure polyamide membrane, respectively.
【学位授予单位】：中国海洋大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ051.893

【相似文献】