Two-dimensional MXene incorporated graphene oxide composite membrane with enhanced water purification performance

Abstract

The limitations of instability and low permeability of graphene oxide (GO) membranes in aqueous applications, such as water treatment, represent significant obstacles to their wider application. In this paper, we describe the development and testing of a novel composite membrane based on GO and MXene. The unique heterogeneous structure of the GO/MXene membrane demonstrated a synergistic effect, in terms of substrate rejection and permeability, which varied according to the relative proportions of GO and MXene. Due to its advantageous two-dimensional (2D) interlayer channels and hydrophilicity, a composite membrane (~550 nm) with a GO/MXene mass ratio of 1/4 exhibited much greater water flux (71.9 L m−2 h−1.bar−1) compared to a reference GO membrane (6.5 L m−2 h−1.bar−1) under the same experimental conditions. Moreover, the composite membrane showed excellent stability in water over one month. The rejection of common small molecule organic dyes (NR, MB, CV, BB) was found to exceed 99.5%, and similar excellent removal efficiencies were found for two representative types of natural organic matter in raw waters (HA and BSA). The superior water flux of the GO/MXene composite membrane compared to the reference GO membrane was mainly attributed to the moderate increase of interlayer spacing of the membrane and the decrease of oxygen-containing functional groups.