(343a) Effect of Molecular Dynamics Water Models on Flux and Diffusivity in Membranes

Despite the broad application of polyamide membranes for water purification and treatment, the interactions between the membrane, water, and solutes are unclear at the molecular level. To better understand these interactions, molecular dynamics simulations are often used to model the filtration process. While realistic membrane models are crucial to investigating the membrane filtration process, the atomistic water model and simulation parameters also play important roles. Previous polyamide membrane simulation studies use a variety of water models along with different molecular dynamics thermostat settings. In this research, we find that the choices for the water model (SPC/E, TIP3P, or TIP4P), thermostat settings, and temperature have significant impact on water flux and diffusivity in simulations of charged nanofiltration membranes. We also compare the water dynamics results obtained through simulations with previous experimental and computational results. This work offers insights into the influence of simulation parameters on water dynamics and which water models most accurately represent real water behaviors in polyamide membrane filtration systems. Funded by NSF Grant CBET-1840816.