层层自组装法制备氧化石墨烯复合单价选择性离子交换膜

Preparation of Monovalent-selective Ion-exchange Membrane with Graphene Oxide Deposition by Layer-by-Layer Assembly

将氧化石墨烯(GO)添加到聚丙烯酸(PAA)溶液中,并与聚乙烯亚胺(PEI)在阳离子交换膜表面通过层层自组装(LBL)法制备了单价选择性离子交换膜。结果表明,PEI为表层的复合膜,具有更高的单价离子选择性,随着层层自组装的进行,GO连续地沉积到膜的表面。复合膜的面电阻随组装层数的增加而增大,相比于未添加GO的多层膜,GO的加入有利于膜电阻的降低。同时,随着自组装层数的增加,复合膜的单价离子分离效率提高;GO浓度升高,复合膜的单价离子选择性先升高后降低,当GO浓度升高至0.5 g/L时,复合膜的分离效率最高。

Monovalent-selective ion-exchange membranes were fabricated by adding graphene oxide(GO)to polyacrylic acid(PAA)and alternately deposited on the surface of cation-exchange membrane with polyetherimide(PEI)through layer-by-layer self-assembly(LBL).The result indicated that the composite membranes terminated with PEI had higher separation efficiency.GO was deposited onto the membrane surface evenly and continuously with the assembly of polyelectrolyte.The surface resistance of the composite membranes increased with the assembled number of bilayers.Moreover,the addition of GO is beneficial to reduce the membrane resistance compared to the multilayer membranes without GO.The composite membranes exhibited improved separation efficiency with the assembled bilayers.Besides,the separation efficiency increased firstly and then decreased with the GO concentration and showed the highest selectivity with GO concentration of 0.5 g/L.