Selective Separation of Metal Ions via Monolayer Nanoporous Graphene with Carboxyl Groups.
Graphene-coated plastic substrates, such as polyethylene terephthalate (PET), are regularly used in flexible electronic devices. Here we demonstrate a new application of the graphene-coated nanoporous PET membrane for the selective separation of metal ions in an ion exchange manner. Irradiation with swift heavy ions is used to perforate graphene and PET substrate. This process could create graphene nanopores with carboxyl groups, thus forming conical holes in the PET after chemical etching to support graphene nanopores. Therefore, a monolayer nanoporous graphene membrane with a PET substrate is constructed successfully to investigate its ionic selective separation. We find that the permeation ratio of ions strongly depends on the temperature and H+concentration in the driving solution. An electric field can increase the permeation ratio of ions through the graphene nanopores, but it inhibits the ion selective separation. Moreover, the structure of the graphene nanopore with carboxyl groups is resolved at the density functional theory level. The results show the asymmetric structure of the nanopore with carboxyl groups, and the analysis indicates that the ionic permeation can be attributed to the ion exchange between metal ions and protons on the two sides of graphene nanopores. These results would be beneficial to the design of membrane separation materials made from graphene with efficient online and offline bulk separation.
Key Laboratory of Chemistry of Northwestern Plant Resources and Key Laboratory for Natural Medicine of Gansu Province, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences , Lanzhou 730000, China.|Institute of Modern Physics, Chinese Academy of Sciences , Lanzhou 730000, China.
Zhan
Z
Li
The School of Nuclear Science and Technology, Lanzhou University , Lanzhou 730000, China.
Yanqi
Y
Liu
Department of Chemistry, State Key Lab of Molecular Engineering of Polymers, Shanghai Key Lab of Molecular Catalysis and Innovative Materials, and Collaborative Innovation Center of Chemistry for Energy Materials, Fudan University , Shanghai 200433, China.
Yang
Y
Zhao
The School of Nuclear Science and Technology, Lanzhou University , Lanzhou 730000, China.
Xin
X
Zhang
The School of Nuclear Science and Technology, Lanzhou University , Lanzhou 730000, China.
Lijuan
L
Qian
School of Radiation Medicine and Protection & School for Radiological and Interdisciplinary Sciences (RAD-X), Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Medical College of Soochow University , Suzhou, Jiangsu 215123, China.
Longlong
L
Tian
Institute of Modern Physics, Chinese Academy of Sciences , Lanzhou 730000, China.
Jing
J
Bai
Institute of Applied Electromagnetic Engineering, School of Electrical and Electronic Engineering, Huazhong University of Science and Technology , Wuhan 430000, China.
Wei
W
Qi
Department of Agriculture and Biological Engineering, University of Florida , Gainesville, Florida 32611, United States.
Huijun
H
Yao
Department of Agriculture and Biological Engineering, University of Florida , Gainesville, Florida 32611, United States.
Bin
B
Gao
Institute of Modern Physics, Chinese Academy of Sciences , Lanzhou 730000, China.
Jie
J
Liu
The School of Nuclear Science and Technology, Lanzhou University , Lanzhou 730000, China.
Wangsuo
W
Wu
Key Laboratory of Chemistry of Northwestern Plant Resources and Key Laboratory for Natural Medicine of Gansu Province, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences , Lanzhou 730000, China.
Hongdeng
H
Qiu