Graphene oxide membranes with short-range pore channels toward ultrafast water transport via γ-ray etching

Abstract

Graphene oxide (GO) has the characteristics of easy membrane formation and adjustable interlayer size, which can achieve molecular/ion separation precisely. However, the stacked GO nanosheets have a large tortuosity factor and long mass transfer channel, which limits the feasibility of GO membranes with high-flux. In this study, we propose the short-range pore channels construction strategy that a γ-ray irradiation pore-making technology is used to increase the in-plane porosity of GO nanosheets, thereby shortening the mass transfer channel and realizing the rapid transmission of water molecules. The in-plane defects and d-spacing of GO, used as the mass transfer channel of the membrane, were finely controlled by the irradiation dose of γ-rays. More in-plane pores and expanded interlayer pathway was introduced into the membrane by adjusting the irradiation dose, which leads to significantly strengthened water permeability. The optimized membrane has a higher pure water permeability (345.23 L m-2h−1 bar−1) and dye rejection (nearly 100 %) as well as excellent dye/salt separation performance (αmax: 109.27), which is superior to GO membranes previous reported in the literature. The porous membrane with short-range pore channels obtained by high-energy irradiation provides a new strategy for preparing two-dimensional membranes with efficient wastewater purification and recovery.