具有pH值响应性纳米通道的氧化石墨烯纳滤膜的制备

Preparation of a graphene oxide nanofiltration membrane with pH-responsive nanochannels

为了改善氧化石墨烯基纳滤膜在应用时结构稳定性差和应用范围窄的问题,利用乙烯基三乙氧基硅烷(VTES)对氧化石墨烯(GO)进行改性,并接枝聚丙烯酸(PAA),获得具有交联结构和pH值响应性的GO-PAA纳滤膜;对GO粉末、GO-VTES粉末、GO-PAA粉末和纳滤膜进行表征,采用染料刚果红、达旦黄、金橙、结晶紫、罗丹明B和碱性红分析纳滤膜的分离性能。结果表明:在酸性环境下,PAA链静电斥力减弱,链收缩,膜分离效果差;在中性或碱性环境下,PAA链静电斥力大,链伸展,膜分离效果好,纳滤膜对阴离子型染料的分离效果均达99%以上,对阳离子型染料均具有99%以上的吸附分离效果。该GO-PAA纳滤膜具有优异的分离效果和结构稳定性,在染料废水处理领域有着广泛的应用前景。

To improve the structural stability and narrow application range of graphite oxide based nanofiltration membrane in application,graphene oxide(GO)was modified with triethoxyvinylsilane(VTES),then poly(acrylic acid)(PAA)was grafted onto GO nanosheets to prepare the GO-PAA nanofiltration membrane with cross-linked structure and pH responsive nanochannels.GO powder,GO-VTES powder,GO-PAA powder and nanofiltration membrane were tested and characterized.The separation performance of nanofiltration membrane was analyzed by dyes Congo red,Titan yellow,gold orange,crystal violet,Rhodamine B and basic red.The results show that in an acidic environment,the electrostatic repulsion between PAA chains is weakened,the PAA chains shrink,and the membrane specific performance is poor;in a neutral or alkaline environment,the electrostatic repulsion between PAA chains increases,the PAA chains stretch,and the membrane separation performance is superior.The nanofiltration membrane has a separation effect of over 99%for anionic dyes,and an adsorption separation effect of over 99%for cationic dyes.To sum up,the GO-PAA nanofiltration membrane has excellent separation performance and structural stability,and has a broad application prospect in the field of dye wastewater treatment.