(398w) Molecular Dynamics Simulations of Zeolite Nanosheets for Water Desalination

Reverse osmosis (RO) water desalination could represent an ideal solution to the increasingly limited availability of fresh water. Such an approach to produce clean water using currently available membranes, however, requires high costs and a considerable amount of energy. Discovering new membranes possessing significantly enhanced water permeability while remaining excellent ability to reject salts is critical. Zeolite nanosheets, ultrathin-film materials with precisely controlled nanostructures as well as good chemical, mechanical, and thermal stability, can be potential RO membrane candidates. In this study, molecular dynamics simulations are used to systematically investigate 27 zeolites with a wide range of geometrical characteristics for desalination. Water permeability and salt rejection are determined from the trajectories of water molecules and salt ions through the zeolite membrane. Our calculations show that orders of magnitude enhancement in water permeability can be achieved, and zeolites with properly chosen structural topologies have a salt rejection of approximately 100%. Moreover, our study establishes the structure-performance relationship for zeolite nanosheet membranes in water desalination, leading to important guidelines for the rational design of zeolite RO membranes. Detailed analysis of free energy barriers for transport is also carried out to better understand the desalination performance of zeolite nanosheets. Overall, zeolite nanosheets have been shown computationally to provide opportunities to RO water desalination. The outcomes of this study can lead to important experimental consequences, facilitating the development of novel zeolite nanosheet membranes for water desalination.

Reference:

Jamali, S.H., Vlugt, T.J.H & Lin, L.-C.*, Atomistic Understanding of Zeolite Nanosheets for Water Desalination, J. Phys. Chem. C, in press, DOI: 10.1021/acs.jpcc.7b00214.