Atomistic understanding of Ti3C2 MXene membrane performance for separation of nitrate ions from aqueous solutions.

Water desalination, which is a reliable method for providing drinking water and a suitable solution, as well as the membrane filtration method in wastewater treatment, has increased significantly in recent years. In this research, the separation of nitrite and nitrate ions from aqueous solutions was done using the MXene membrane of the Ti3C2 type using molecular dynamics simulation. In this study, various parameters, such as pore size MXene structure, characteristics of cavities, applied pressure, and flux were investigated. To investigate the removal of toxic pollutants from water, water flux, potential mean force, distribution of water molecules, and density were investigated. The results showed that the amount of penetration through the membrane increased with the increase in pressure. It was observed that by applying pressure to the system, the number of water molecules accumulated in front of the membrane decreases because they quickly pass through the membrane, which indicates the positive effect of increasing pressure on the separation rate of molecules. The permeability of this membrane was several times higher than the existing membranes in the industry. So that Mexene membranes, which consist of at least two layers, can repel ions with 100 % success.

Rectification, transport properties of doped defective graphene nanoribbon junctions.

The transport properties and rectification behavior of junctions which contain armchair graphene nanoribbons (AGNRs) with double vacancy defects or nitrogen-doped in three different sizes of 9, 10 and 12 atoms are studied. The non-equilibrium Green function method and density functional based tight-binding approach are used for different computations. The double vacancy (DV) defects are along the direction of current pathways of graphene devices. We calculated transmission probability, density of states, the current-voltage curves, rectification ratio, and electrodes band structures. We found that I-V graph has nonlinear characteristic and displays rectification behavior. Devices which posses the size of 9 atoms show significant sign of rectification in contrast to other cases (10, 12 atoms). But the current value is more important for the device of 12 atoms size. Moreover, it is shown that extra energy bands are created by the DV defects and nitrogen (N) doped atoms. These bands of DV defects and N-doped cause the Fermi level to shift upwards and can change the behavior (n-type semiconductor, or metal-like) of devices of 9, 10 and 12 AGNRs. Also, various orbital distributions of MPSH (molecularly projected self-consistent Hamiltonian) states in the DV-9AGNR device are investigated.