摘要
Abstract
Membrane cleaning is a critical step in membrane technology.Although advanced oxidation processes are widely used for organic fouling removal,the impact of the generated free radicals on the structure and performance of organic membrane materials still requires in-depth research.Based on this,a systematic evaluation is conducted to assess the aging effects of advanced oxidation techniques(Fenton system,activated persulfate system)and traditional chemical cleaning agents(NaClO)on Polyether Sulfone(PES)ultrafiltration membranes.Through analysis of separation performance,physicochemical characteristics,and functional group structures,it was found that the hydroxyl radical(·OH)generated by the Fenton system caused minimal damage to the PES membrane structure.After 96 h treatment,the porosity increased only to 35.00%,and the flux ratio did not exceed 2,indicating that its oxidative effect was selective and localized.The sulfate radical(SO4·-)produced by the activated persulfate system exhibited stronger oxidation capacity,leading to a porosity increase of 37.29%and a flux ratio reaching 7.34.In contrast,NaClO demonstrated the most significant non-selective oxidative effect,with a porosity increase of 76.6%and a flux ratio as high as 7.61.Infrared spectroscopy revealed a notable reduction in the intensity of sulfone and aromatic structural peaks,along with the emergence of carbonyl peaks,indicating drastic changes on the membrane surface accompanied by molecular chain reorganization.Scanning Electron Microscope(SEM)and contact angle analysis further confirmed that NaClO treatment accelerated the leaching of hydrophilic agent Polyvinyl Pyrrolidone(PVP)and pore enlargement,resulting in enhanced membrane hydrophobicity.Mechanistic studies demonstrated that the type of free radical and oxidation mode are key factors influencing membrane aging.These findings provide a theoretical basis for optimizing oxidative cleaning processes and balancing membrane service life.关键词
膜老化/芬顿体系/活化过硫酸盐体系/聚醚砜(PES)Key words
membrane aging/Fenton system/activated persulfate system/Polyether Sulfone(PES)分类
化学工程
