Abstract:

A novel poly (vinylidene fluoride) (PVDF)/graphene oxide (GO) membrane with an amount of silver carbonate (Ag₂CO₃) deposition was prepared by both the phase-inversion method and the in situ co-precipitation reaction, respectively. The casting solution of Ag₂CO₃@ PVDF/GO membrane (AgC-PGM) is composed of PVDF as the polymer matrix, GO and Ag₂CO₃ powders as additives, PVP -K30 as the pore-forming agent, and dimethylacetamide (DMAc) as the solvent. The morphology and performances of the AgC-PGM were investigated using scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), contact angle, the BSA rejection and cross flow filtration. Moreover, the separation effect of the lake water was also observed by three-dimensional excitation fluorescence spectrum matrix (3D-EEM). The results indicated that the AgC-PGM exhibited good hydrophilicity and filtering quality, and the pure water flux increased from 132.8 to 237.4 L·m^-2·h^-1, meanwhile the rejection for the BSA solution stabilized around 75% as the GO loading amount to 0.4% (mass), AgNO₃ (5.0 mmol·L^-1)/Na₂CO₃ (2.5 mmol·L^-1) precipitating 3 times. In addition, compared to the PVDF membrane, the 3D-EEM of the lake water shows a better removal effect on the protein pollutant, the removal efficiency of both COD_Mn and UV₂₅₄ separately achieved about 95% and 83% when the AgC-PGM was used to filter the surface water continuously, which has reached to the national primary standard.

Key words: membrane, filtration, seperation, poly (vinylidene fluoride), graphene oxide, silver carbonate

摘要：

以聚偏氟乙烯（PVDF）为聚合物，氧化石墨烯（GO）为添加剂，聚乙烯吡咯烷酮（PVP-K30）为致孔剂，N，N-二甲基乙酰胺（DMAc）为溶剂配制铸膜液，借助相转化法制备了PVDF/GO膜（PGM），并通过原位共沉反应在PGM表面沉积Ag₂CO₃得到Ag₂CO₃@PVDF/GO复合膜（AgC-PGM）；使用扫描电镜（SEM）、傅里叶红外光谱（FTIR）、水接触角、纯水通量、BSA截留率和三维荧光光谱（3D-EEM）考察了膜材料的形貌、亲水性、水通量和分离性。结果表明，当添加GO为0.4%（质量），AgNO₃（5.0 mmol·L^-1）与Na₂CO₃（2.5 mmol·L^-1）共沉反应3次得到AgC-PGM；与PVDF膜（132.8 L·m^-2·h^-1）相比，AgC-PGM呈现出较高的亲水性和纯水通量（237.4 L·m^-2·h^-1），其纯水通量提高了78.8%，对BSA截留率稳定在75%以上；在过滤校区湖水时，AgC-PGM不仅凸显去除蛋白质污染的能力，且出水COD和UV₂₅₄达到自然水体一级标准。

关键词: 膜, 过滤, 分离, 聚偏氟乙烯, 氧化石墨烯, 碳酸银