Titanium Carbide MXene for Water Desalination: A Molecular Dynamics Study

Abstract

The energy-efficient desalination of seawater has been sought as a solution to the challenge of providing society with fresh water. With the recent advances in nanotechnology, nanoporous 2D materials are developed and studied as potential membranes for efficient water desalination. Here we study the desalination performance of a class of MXenes, titanium carbides (Tin+1Cn), via conducting extensive molecular dynamics simulations. We show that 50 Å2 nanopores on Ti3C2 membranes can effectively reject >99% ions with a 20–55% higher permeation rate than graphene, MoS2, and other MXene membranes. Parameters such as the pore size, MXene structure, and pore chemistry are shown to influence the water flux. We demonstrate that pores with titanium on their edges result in a higher flux than carbon-terminated pores. The observations are supported by analyzing the permeability coefficient, the energy barrier, the interfacial water structure near the membrane, and the water packing and mass flux inside the pore.