My research focused on investigating saltwater transport through nanoporous graphene membranes using molecular dynamics (MD) simulations. Particularly, in this dissertation, we focused on pressure-driven flows of salt water through uncharged and charged nanoporous graphene membranes for water desalination applications. In the first study, desalination performance of uncharged single-layer nanoporous graphene membranes was observed based on volumetric flow rate, required pressure drop, and salt rejection efficiency. A functional relationship between the volumetric flow rate, pressure drop, pore diameter, and the dynamic viscosity of saltwater was also examined. In further studies, transport of salt ions through positively and negatively charged single-layer nanoporous graphene membranes with large hydraulic diameters was investigated. I discovered that the positively charged membranes are better than the negatively charged ones in filtering salt ions. The largest pore diameter for which positively charged single-layer graphene membranes still conserve high salt rejection efficiency (≥ 98%) is 18.9 Å. I also showed that using charged bilayer graphene membranes is a good remedy, in which, perfect salt rejection can be obtained while pressure drop is lower than that required for the uncharged single-layer graphene membranes with the same salt removal efficiency.
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Nguyen, Thanh Chinh, "Graphene-Based Water Desalination Using Atomistic Simulations" (2019). Mechanical Engineering Research Theses and Dissertations. 20.