Ion selection of charge-modified large nanopores in a graphene sheet

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

98 Scopus Citations
View graph of relations

Author(s)

Detail(s)

Original languageEnglish
Article number114702
Journal / PublicationJournal of Chemical Physics
Volume139
Issue number11
Online published17 Sept 2013
Publication statusPublished - 21 Sept 2013
Externally publishedYes

Abstract

Water desalination becomes an increasingly important approach for clean water supply to meet the rapidly growing demand of population boost, industrialization, and urbanization. The main challenge in current desalination technologies lies in the reduction of energy consumption and economic costs. Here, we propose to use charged nanopores drilled in a graphene sheet as ion exchange membranes to promote the efficiency and capacity of desalination systems. Using molecular dynamics simulations, we investigate the selective ion transport behavior of electric-field-driven KCl electrolyte solution through charge modified graphene nanopores. Our results reveal that the presence of negative charges at the edge of graphene nanopore can remarkably impede the passage of Cl- while enhance the transport of K+, which is an indication of ion selectivity for electrolytes. We further demonstrate that this selectivity is dependent on the pore size and total charge number assigned at the nanopore edge. By adjusting the nanopore diameter and electric charge on the graphene nanopore, a nearly complete rejection of Cl- can be realized. The electrical resistance of nanoporous graphene, which is a key parameter to evaluate the performance of ion exchange membranes, is found two orders of magnitude lower than commercially used membranes. Our results thus suggest that graphene nanopores are promising candidates to be used in electrodialysis technology for water desalinations with a high permselectivity.

Citation Format(s)

Ion selection of charge-modified large nanopores in a graphene sheet. / Zhao, Shijun; Xue, Jianming; Kang, Wei.
In: Journal of Chemical Physics, Vol. 139, No. 11, 114702, 21.09.2013.

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review