基于多巴胺亲水改性的聚丙烯中空纤维膜及油水分离性能研究

Polypropylene hollow fiber membrane based on dopamine hydrophilic modification and oil-water separation performance study

基于多巴胺(DA)氧化自聚合机理,通过3-(2,3-环氧丙氧)丙基三甲氧基硅烷(KH560)上的环氧基与聚乙烯亚胺(PEI)上的伯胺发生开环反应,使两者交联并涂覆于聚丙烯中空纤维膜(PPHFM)表面,然后DA在弱碱性环境下被氧化成醌基与PEI的氨基发生迈克尔加成或席夫碱反应,使DA进一步与PEI交联,进而涂覆在膜表面.通过ATR-FTIR、XPS、SEM和AFM对膜表面化学组成和表面形貌进行表征,还对改性膜进行亲水性和油水分离性能测试.结果表明,改性膜的纯水通量从原膜的(124.8±6.3)kg/(m^(2)·h)提高到(363±8.1)kg/(m^(2)·h).对不同种类的水包油乳液的分离效率均达96%以上,通量恢复率均高于86%,说明改性膜PPHFM-KH560/PEI-PDA具有较好的渗透性、抗油污染性能和重复使用性能.此外,改性膜在酸性、弱碱性和高浓度盐溶液环境下均表现出良好的化学稳定性,有利于高效地处理复杂成分的含油废水,具有广阔的应用前景.

Based on the oxidative self-polymerization mechanism of dopamine(DA),the two were cross-linked and coated on the surface of polypropylene hollow fibre membrane(PPHFM)through a ring-opening reaction between the epoxy group on 3-(2,3-epoxypropyloxy)propyltrimethoxysilane(KH560)and a primary amine on polyethyleneimine(PEI),and then dopamine(DA)is oxidized to quinone groups in a weakly alkaline environment and reacts with the amino group of the PEI in a Michael addition or Schiff base reaction,which further cross-links the DA with the PEI,which is then coated on the film surface.The membrane surface chemical composition and surface morphology were characterised by ATR-FTIR,XPS,SEM and AFM,and the hydrophilicity and oil-water separation properties of the modified membrane were also tested.The results showed that the pure water flux of the modified membrane was increased from(124.8±6.3)kg/(m^(2)·h)of the original membrane to(363±8.1)kg/(m^(2)·h).The separation efficiencies for different types of oil-in-water emulsions were all above 96%,and the flux recovery rates were all higher than 86%,indicating that the PHFM-KH560/PEI-PDA membranes have good permeability,resistance to oil contamination and reusability.In addition,the modified membranes showed good chemical stability in acidic,weakly alkaline and high concentration salt solution environments,which is conducive to the efficient treatment of oily wastewater with complex composition and has broad application prospects.