| Membrane separation technology has widely used due to its high separation efficiency and low cost compared to the traditional ways toward wastewater treatment.Poly(vinylidene fluoride)(PVDF),a common polymer material,has always been used to prepare microfiltration and ultrafiltration membrane because of its good stability.However,the inherent hydrophobicity of PVDF membrane would result in two major problems when it used as membrane material employed in the field of wastewater treatment.One is that its inherent hydrophobicity limited the improvement of water flux of membrane;another is that PVDF membrane was prone to adsorb oil and protein pollutants in water,blocking membrane pores,and reducing the water flux of membrane,and further resulting the decrease of span of membrane.Improving the hydrophilicity of PVDF membrane is an effective method to solve these two problems.Herein,the hydrophilicity of PVDF membrane was enhanced based on the natural adhesion of plant polyphenol tannin acid and high hydrophilicity of zwitterion.The chemical construction,water flux,surface wettability,antifouling property and usability of membranes before and after modification were investigated by adjusting the preparation conditions.The work of this paper was consist of two part: one is to improve the hydrophilicity of PVDF microfiltration membrane,the modified membrane could effectively resist oil pollution and be used in efficiently separating various oil-in-water emulsions;the other is to enhance the hydrophilicity of PVDF ultrafiltration membrane,the surface of modified membrane was endowed with anti-adsorption of protein and the membrane can be used in intercepting the protein contaminant in water efficiently.The modification strategy proposed in this paper significantly improved the hydrophilicity and separation performance of PVDF membrane,provided a reference method for the research of membrane hydrophilicity modification,and also promoted biomimetic surface engineering based on plant polyphenols. |
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