Preparation And Application In Esterification Wastewater Treatment Of Polyvinylidene Fluoride/Polyphenylene Sulfone Blending Membrane

Esterification wastewater was emitted during polyester production, it had some features such as low pH (2-3), complex organic components, high stability and poor biodegradation, so it's essential to take some measures to treat esterification wastewater. At present, due to the membrane method, especially membrane bioreactor has many advantages such as stable treating effect and simple running management, was widely adopted to treat wastewater. However, the development of membrane methods were still greatly restricted by membrane fouling, it's essential to modify the membrane performance and reduce the membrane fouling.Firstly, preparation of polyvinylidene fluoride (PVDF)/polyphenylene sulfone (PPSU) blending membrane was studied by L25(56) orthogonal array, the effects of PVDF/PPSU blending ratio, polymer concentration and additives (LiCl, MgCl2, PEG-2000) concentration on PVDF/PPSU blending membrane performances (water flux, rejection, hydrophilicity) and membrane inner structure were investigated. Optimal blending membranes were obtained and adopted to treat esterification wastewater through indoor prepared submerged MBR.It was found that the best water flux, rejection and contact angle of blending membrane were 3300.0 L/m2·h,60.0% and 67°, respectively. Meanwhile, polymer concentration was proved to be the main factor affecting water flux, rejection even contact angle via orthogonal polar difference analysis. The results showed that with PVDF/PPSU blending ratio changed from 9:1 to 5:5, water flux increased but rejection and contact angle decreased; with the polymer concentration changed from 11.0 wt.% to 19.0 wt.%, water flux and contact angle decreased but rejection went up; with the additive (LiCl, MgCl2, PEG-2000) concentration increased, water flux and rejection slightly change but contact angle decreased obviously. When additive was PEG-2000, the membrane had the best comprehensive performance.Meanwhile, the optimal membranes were adopted to treat esterification wastewater (pre-processed) by MBR, the optimal operation paraments was determined:HRT (hydraulic retention time) was 24 h, aeration intensity (air) was 0.012 MPa.Compared with neat PVDF membrane, comprehensive analysis showed that the PVDF/PPSU blending membrane was more resistant to pollution and had higher water flux, better hydrophilicity. When the optimal blending membranes were adopted to treat esterification wastewater, steady treatment efficiency was obtained.