Novel two-dimensional fused pentagon monolayer as a separation membrane with high desalination properties

YT Niu and K Meng and T Xu and JL Wang and XX Xiao and J Rong and XH Yu and YN Zhang and Y Wei, DIAMOND AND RELATED MATERIALS, 140, 110448 (2023).

DOI: 10.1016/j.diamond.2023.110448

The contradiction between supply and demand of freshwater, which has emerged as a global concern, is intensifying as the continued growth of the population on earth, and desalination serves as a tactic to enable open source increment of water resources. Lately, fused pentagon, a hypothetical two-dimensional (2D) carbon allotrope, has focused the attention of researchers due to its extensive five-membered multiple- ring structure and superior properties. However, the potential solute transport mechanism of fused pentagon as a 2D reverse osmosis desalination membrane has not been profoundly elucidated. Here, we combine density functional theory (DFT) and molecular dynamics (MD) to explore the promising feasibility of fused pentagon with abundant penta- carbon rings for desalination applications, and further analyze the properties superiority of such materials featuring periodic pore structures from the electronic level. The results indicate that the membrane structure constructed by a uniform distribution of enriched pentagonal and dodecagonal pores exhibits exceptional structural stability and satisfactory resistance to salt ion aggregation. Compared with other 2D materials, the 12-membered carbon rings of fused pentagon demonstrate remarkable Na ions adsorption properties (adsorption energy value is -2.049 eV, which is superior than those of the compared 2D materials), with a charge transfer of 0.68 |e| as Na ions across the membrane. Moreover, with the physical pressure increased to 95 MPa, the salt ions rejection rate of fused pentagon could present >92.31 % while preserving superior water molecule penetration, which evidences its favorable desalination properties. Promisingly, fused pentagon manifests intrinsic metallicity, which facilitates self-cleaning upon electrical stimulation. This work clarifies the desalination mechanism of fused pentagon monolayer from a theoretical perspective and contributes to an innovative research concept for the development of carbon-based reverse osmosis materials.

Return to Publications page