An asymmetric membrane of polyimide 6FDA-BDAF and its pervaporation desulfurization for n-heptane/thiophene mixtures
YANG Xiang-dong, YE Hong, LI Yan-ting, LI Juan, LI Ji-ding, ZHAO Bing-qiang, LIN Yang-zheng
1、Institue of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, P.R.China
2、Department of Chemical Engineering, Tsinghua University, Beijing 100084, P.R.China
3、School of Food and Chemical Engineering, Beijing Technology and Business University, Beijing 100048, P.R.China
4、Geophysical Laboratory, Carnegie Institution of Washington, Washington, D.C. 20015, USA
摘要 Polyimide (PI) is a type of important membrane material. A soluble polymer was synthesized from 4,4´-(hexafluoroisopropylidene) diphthalic anhydride (6FDA) and 2,2-bis[4-(4-aminophenoxy) phenyl] hexafluoropropane (BDAF) by the two-step polymerization method. The polymer was proved to be polyimide 6FDA-BDAF by the Fourier transform infrared (FT-IR), the 1H-NMR and 19F-NMR spectra. An asymmetric membrane was prepared with the synthesized polyimide 6FDA-BDAF, it was porous in the 50 μm height bulk and dense in a 3–5 μm height surface. The membrane was used to separate n-heptane/ thiophene mixtures by pervaporation with sulfur (S) contents from 50 to 900 μg g–1. The total flux was enlarged from 7.96 to 37.61 kg m–2 h–1 with temperature increasing from 50 to 90°C. The membrane’s enrichments factor for thiophene were about 3.13 and dependent on the experimental conditions. The experimental results demonstrated that polyimide 6FDA-BDAF would be a potential membrane material for desulfurization and controlled release of the S-containing fertilizer.
Abstract Polyimide (PI) is a type of important membrane material. A soluble polymer was synthesized from 4,4´-(hexafluoroisopropylidene) diphthalic anhydride (6FDA) and 2,2-bis[4-(4-aminophenoxy) phenyl] hexafluoropropane (BDAF) by the two-step polymerization method. The polymer was proved to be polyimide 6FDA-BDAF by the Fourier transform infrared (FT-IR), the 1H-NMR and 19F-NMR spectra. An asymmetric membrane was prepared with the synthesized polyimide 6FDA-BDAF, it was porous in the 50 μm height bulk and dense in a 3–5 μm height surface. The membrane was used to separate n-heptane/ thiophene mixtures by pervaporation with sulfur (S) contents from 50 to 900 μg g–1. The total flux was enlarged from 7.96 to 37.61 kg m–2 h–1 with temperature increasing from 50 to 90°C. The membrane’s enrichments factor for thiophene were about 3.13 and dependent on the experimental conditions. The experimental results demonstrated that polyimide 6FDA-BDAF would be a potential membrane material for desulfurization and controlled release of the S-containing fertilizer.
The authors greatly appreciate the support from the Key Technology R&D Program of China (2011BAD11B05) and the National Nonprofit Institute Research Grant of Chinese Academy of Agricultural Sciences (2011-28; 2013-17). This work was supported by the National Basic Research Program of China (973 Program, 2003CB615701), the National Natural Science Foundation of China (20576059, 20676067, 31572204), the China Petroleum & Chemical Corporation (SINOPEC Foundation, X505002) and the China National Petroleum Corporation (CNPC) Innovation Foundation (05051143).
YANG Xiang-dong, YE Hong, LI Yan-ting, LI Juan, LI Ji-ding, ZHAO Bing-qiang, LIN Yang-zheng.
2015.
An asymmetric membrane of polyimide 6FDA-BDAF and its pervaporation desulfurization for n-heptane/thiophene mixtures. Journal of Integrative Agriculture, 14(12): 2529-2537.
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