A novel strategy for enhancing the performance of membranes for dyes separation: Embedding PAA@UiO-66-NH2 between graphene oxide sheets

Abstract

A composite membrane based on a novel strategy was prepared which using graphene oxide (GO), UiO-66-NH2 and polyacrylic acid (PAA) as basic materials on the surface of nylon membrane by vacuum filtration self-assembly. The structure of the composite membrane was made of graphene oxide as vertical separation layer, the PAA@UiO-66-NH2 (PAA@UiO) embedding between GO as horizontal capture material. The PAA@UiO-66-NH2/GO (PAA@UiO/GO) membrane was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and atomic force microscopy (AFM). Compared with the GO membrane, PAA@UiO/GO membrane combined the effects of GO, UiO-66-NH2 and PAA, which significantly enhances the separation performance of dye wastewater. In particular, the PAA@UiO/GO membrane can achieve complete removal of MB, RB and CR while the fluxes during filtration process can reach about 100 L∙m-2∙h-1. At the same time, PAA@UiO/GO membrane almost retained stable removal rate on all dyes under extreme pH and ionic strength conditions. In addition, after 10 cycles of experiments, PAA@UiO/GO membrane retained a removal rate and a flux more than 95% and 85 L∙m-2∙h-1for all dyes, respectively. Compared to a composite membrane based on intercalation, the unique structure of PAA@UiO/GO membrane with a large number of adsorption sites and screening structures, resulting a better removal rate for dyes. Furthermore, PAA@UiO/GO membrane has a great potential in practical applications and a solution to balance trade-off effect.