Strong Differential Monovalent Anion Selectivity in Narrow Diameter Carbon Nanotube Porins
- 29 April 2020
- journal article
- research article
- Published by American Chemical Society (ACS) in ACS Nano
- Vol. 14 (5), 6269-6275
- https://doi.org/10.1021/acsnano.0c02423
Abstract
Inner pores of carbon nanotubes combine extremely fast water transport and ion selectivity that could potentially be useful for high-performance water desalination and separation applications. We used dye-quenching halide assays and stopped-flow spectrometry to determine intrinsic permeability of three small monovalent halide anions (chloride, bromide, iodide) and one pseudo-halide anion (thiocyanate) through narrow 0.8 nm-diameter carbon nanotube porins (CNTPs). These measurements revealed unexpectedly strong differential ion selectivity with permeabilities of different ions varying by up to two orders of magnitude. Removal of the negative charge from the nanotube entrance increased anion permeability by only a relatively small factor, indicating that electrostatic repulsion was not a major determinant of CNTP selectivity. First principle molecular dynamics simulations revealed that the origin of this strong differential ion selectivity is partial dehydration of anions upon entry into the narrow CNTP channels.Funding Information
- Basic Energy Sciences (DE-SC0019112)
- Government of Jiangsu Province (KYCX18_0067)
- China Scholarship Council (201806090020)
- Graduate School, Southeast University (YBJJ1802)
This publication has 51 references indexed in Scilit:
- Experimental Energy Barriers to Anions Transporting through Nanofiltration MembranesEnvironmental Science & Technology, 2013
- Selective Ion Passage through Functionalized Graphene NanoporesJournal of the American Chemical Society, 2008
- Development of synthetic membrane transporters for anionsChemical Society Reviews, 2006
- Salt screening and specific ion adsorption determine neutral-lipid membrane interactionsProceedings of the National Academy of Sciences of the United States of America, 2006
- Absolute Hydration Free Energy Scale for Alkali and Halide Ions Established from Simulations with a Polarizable Force FieldThe Journal of Physical Chemistry B, 2006
- The Structure of the Potassium Channel: Molecular Basis of K + Conduction and SelectivityScience, 1998
- Periodic boundary conditions inab initiocalculationsPhysical Review B, 1995
- Ionic selectivity revisited: The role of kinetic and equilibrium processes in ion permeation through channelsThe Journal of Membrane Biology, 1983
- The Dielectric Constant of Phospholipid Bilayers and the Permeability of Membranes to IonsScience, 1979
- Chloride flux in bilayer membranes. Chloride permeability in aqueous dispersions of single-walled, bilayer vesiclesBiochemistry, 1975