Ion exclusion by sub-2-nm carbon nanotube pores

• DOI: 10.1073/pnas.0710437105
• Publication Date: 2008-06-07T01:09:54Z
• Authors: Francesco Fornasiero; Hyung Gyu Park; Jason K. Holt; Michael Stadermann; Costas P. Grigoro...; Aleksandr Noy; Olgica Bakajin
• Keywords: MECHANISM; Electrophoresis; Anions; Osmosis; Openings; Static Electricity; Transport; 02 engineering and technology; Ion Channels; ion transport; 37 Inorganic; EXTRACELLULAR LOOP; PERMEATION; Electrostatics; Cations; INORGANIC METAL-CATIONS; biomimetic platform; WATER; CRYSTAL-STRUCTURE; Seawater; Fluid Flow; Ions; Membranes; Organic; Nanotubes; Ion Transport; Desalination; Nanotubes, Carbon; 36 Materials Science; Water; TRANSPORT; Carbon; Oxygen; Valence; nanofiltration; ion channel; SEPARATION; Physical And Analytical Chemistry; Zeolites; Hydrodynamics; POTASSIUM CHANNEL; PROTON TRANSLOCATION; 0210 nano-technology; Porosity

Biological pores regulate the cellular traffic of a large variety solutes, often with high selectivity and fast flow rates. These share several common structural features: inner surface pore is frequently lined hydrophobic residues, filter regions contain charged functional groups. Hydrophobic, narrow-diameter carbon nanotubes can provide simplified model membrane channels by reproducing these critical features in simpler more robust platform. Previous studies demonstrated that nanotube support water flux comparable to natural aquaporin channels. Here, we investigate ion transport through using sub-2-nm, aligned nanofluidic To mimic groups at region, introduce negatively opening plasma treatment. Pressure-driven filtration experiments, coupled capillary electrophoresis analysis permeate feed, are used quantify exclusion membranes as function solution ionic strength, pH, valence. We show exhibit significant be 98% under certain conditions. Our results strongly Donnan-type rejection mechanism, dominated electrostatic interactions between fixed charges mobile ions, whereas steric hydrodynamic effects appear less important.