Novel “loose” GO/MoS2 composites membranes with enhanced permeability for effective salts and dyes rejection at low pressure

Graphene oxide-based nanofiltration membrane, have attracted tremendous interest due to the highly permeability and excellent rejection behavior. Here we show that a novel low-pressure nanofiltration membranes (LPMs) comprising MoS 2 nano-supporting spacer among the graphene oxide (GO) layers, which were fabricated by forward pressure-assisted assembly and heat-treatment. The resultant GO/MoS 2 LPMs exhibited a pure water permeability about 10.2 ± 1.68 L/(m 2 ·h·bar) at low pressure (2 bar), which was much higher ( about 13.6 times) than that of pristine GO membrane (~0.75 L/(m 2 h bar)). Meanwhile, high rejection to different charged dyes ( ≥ 95%) and moderate rejection for salts (43.2%, 65.2%, 26.5% and 24.3% for NaCl, Na 2 SO 4 , MgCl 2 and MgSO 4 , respectively) was remained. The satisfied filtration performance was attributed to the loose interlayer-structure of composite membrane and the cooperative effect of Gibbs-Donnan exclusion mechanism and steric hindrance. In addition, the GO/MoS 2 LPMs presented satisfied stability and antifouling properties. Experimental results and molecular dynamics simulation results demonstrated that the increase of vertical distance between GO sheets by introducing the MoS 2 nanoparticles could accelerate the water transport in the channels. This paper was not only provided a new design idea for adjusting the channel size of GO membrane, but also gave a promise of GO-based membrane for practical wastewater treatment and purification.