Fabrication of a Superhydrophilic and Underwater Superoleophobic Membrane via One-Step Strategy for High-Efficiency Semicoking Wastewater Separation
journal contributionposted on 2022-04-18, 19:11 authored by Yujia Tong, Jinbo Chen, Wenlong Ding, Lijian Shi, Weixing Li
Hydrophilic polyvinylidene fluoride (PVDF) membranes can effectively separate the low oil content in semicoking wastewater. It is important to develop a stable superhydrophilic PVDF membrane with high oil rejection. Here, we developed a one-step strategy based on a polyphenol netlike structure coating to achieve the conversion of commercial membranes from hydrophobic to superhydrophilic; namely, the codeposition of 2-propenamide, N-[2-(3,4-dihydroxyphenyl)ethyl] (DMA) and 3-aminopropyltriethoxysilane (APTES) in aqueous solution. ATR-FTIR and XPS technologies proved that the coating successfully adhered to the PVDF membrane. The pure water flux of the developed membrane was 17 270 L m–2 h–1 bar–1. When treating simulated semicoking wastewater with low oil content, the permeate flux and the oil content of the filtrate were 5500 L m–2 h–1 bar–1 and <6.5 mg L–1, respectively. The modified PVDF membrane showed perfect wetting performance. The permeation flux of the real semicoking wastewater cycled 9 times was stable at 4530 L m–2 h–1 bar–1 and the oil content of the filtrate was <12.5 mg L–1. This work emphasizes a simple way to design superhydrophilic membranes for the separation of low-oil content emulsion, which will be promising for treating semicoking wastewater.
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