One-step preparation of a superhydrophilic membrane with excellent anti-oil fouling property for simultaneous separation of emulsified oils and dyes in complex wastewater

Jun Zhang, Dawei Luo, Lihao Yao, Jiaxin Guo, Jinhao Zhang,Cuiyin Liu,Jingjing Li,Xinjuan Zeng,Min Zhang,Shaozao Tan


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As reported herein, an environmentally friendly superhydrophilic membrane with underwater superoleophobicity was prepared for the efficient separation of oil-in-water emulsions and dyes. The preparation of this superhydrophilic membrane is very simple, requiring only a one-step modification of polyvinylidene fluoride (PVDF) membranes by ionic chelation of phytic acid (PA) and polydopamine (PDA) in an aqueous solution (PA@PDA/PVDF). The PA@PDA/PVDF membrane shows superhydrophilicity in air with pure water permeance reaching up to 98354 ± 1574 L m −2 h −1 bar −1 and underwater oil contact angles (UWOCAs) greater than 150°. The high water permeance and excellent underwater superoleophobicity of the PA@PDA/PVDF membrane give it excellent oil–water separation performance, thus enabling it to separate various oil-in-water emulsions with high efficiency above 95.2% and permeance up to 48855.3 ± 3752 L m −2 h −1 bar −1 . Moreover, the PA@PDA/PVDF membrane shows remarkable recoverability and excellent anti-oil fouling property during the separation of emulsified oily wastewater. The remaining catechol groups of PDA and the phosphate groups of PA endow the PA@PDA/PVDF membrane with significant electronegativity, so that it can be used to efficiently separate dye wastewater by filtration through electrostatic adsorption. More importantly, the PA@PDA/PVDF membrane can simultaneously remove organic contaminants from complex wastewaters containing emulsified oils and dyes in just one filtration process, with a total efficiency above 92%. Thanks to its simple and environmentally friendly preparation method and excellent separation performance, the PA@PDA/PVDF membrane shows great potential for the practical treatment of complex wastewaters containing a wide range of organic pollutants. Graphical abstract
superhydrophilic membrane,emulsified oils,complex wastewater,one-step,anti-oil
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