A Sm-MOF/GO nanocomposite membrane for efficient organic dye removal from wastewater

The instability of graphene oxide (GO) membranes in aqueous solutions restricts their application in wastewater treatment through the membrane separation technology. In this work, a nanocomposite membrane (Sm-MOF/GO) composed of samarium metal-organic frameworks (Sm-MOFs) and GO nanosheets was successfully fabricated via the filtration of the corresponding Sm-MOF/GO dispersions. The in situ growth of Sm-MOF with aqueous stability on the GO sheets prevented the adjacent GO layers from expanding in aqueous solutions, thus endowing the prepared Sm-MOF/GO membrane with a stable membrane skeleton structure. Besides, the successful loading of Sm-MOF enlarged the layer space of the composite membrane, which was beneficial for higher permeance. The optimization of the Sm-MOF loading contents was also investigated to prepare M-X (where X represents the mass ratio of the MOF raw material to the total mass of the reactants). Subsequently, the fabricated M-0.31 possessed a high permeance of 26 L m^-2 h^-1 bar^-1, which was 3 times higher than that of a pure GO membrane; moreover, high rejections (>91%) to rhodamine B and methylene blue were obtained. After continuous 5.5 h filtration, the excellent rejection was still maintained as expected, indicating the long-term stability of M-0.31.