Molecular Dynamics Simulation of Transport Mechanisms and Desalination Performance of the PSF/UiO-66 Thin-film Composite Membrane

A novel molecular dynamics (MD) model was presented to investigate the transport mechanisms and desalination performance of a series of thin-film composite membranes. Firstly, polyamide (PA) and polysulfone (PSF), or PSF/UiO-66 was constructed by cross-linking reactions as an active layer and a support layer of the composite membrane. Subsequently, feed solution and three draw aqueous solutions with salt concentrations of 0.5, 1.0 and 1.5 M were generated by GROMACS, a molecular dynamics software that can places different solutions into separate boxes. Thirdly, these aqueous boxes and membranes were combined such that the active layer faced the feed solution or the draw solution. The forward osmosis (FO) process was then applied to anatomize the membrane fouling, water flux, and salt rejection. The results indicated that the PA-PSF/UiO-66 membrane exhibited a strong antifouling effect, high water transport and salt rejection performances compared to the pristine PA and PA-PSF membranes. This simulation work provided important insight in guiding the design and synthesis of the FO membrane.