Transport of Water Contaminated with Various Ions Through Nanoporous Graphene: A Molecular Dynamics Simulation

M Rahiminejad and V Mortazavi and A Moosavi and A Nouri-Borujerdi, TRANSPORT IN POROUS MEDIA, 146, 537-557 (2023).

DOI: 10.1007/s11242-022-01870-9

Through extensive MD simulations, desalination of water contaminated with various ions including Na+, K+, Mg2+, Ca2+, and Cl- through monolayer graphene is explored, and the influences of nanopore diameter, applied pressure, contaminant concentration, and functional groups on the number of permeated water through the membrane and ion rejection are quantified. Obtained results reveal that there exists an optimum pore diameter in which maximum ion rejection by the membrane occurs. Also, it is demonstrated that the hydration energy of ions is potentially effective in ion rejection, so ions with lower hydration energy are more likely to pass through the membrane. This conclusion applies to all contaminant concentrations. Moreover, it is found that the effect of increasing the external pressure on the water permeability is more for the membranes with smaller diameters. This observation may be crucial in designing such membranes. Finally, it is shown that the hydroxylated pore has higher water permeability than the carboxylated pores. In contrast, the carboxylated pore is better at ion rejection than the hydroxylated and pristine pores.

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