Polysulfone‐based composite membranes with functionalized carbon nanotubes show controlled porosity and enhanced electrical conductivity

Abstract

ABSTRACTComposite membranes of functionalized (–COOH, –CONH2, –N3) carbon nanotubes/polysulfone (CNT/PS) synthesized by the phase‐inversion method show unique properties with respect to surface characteristics and the selective separation of metal ions from aqueous solution. Apart from the reduction in the pore size depending on the type of functionalities on the nanotubes, the pure water permeation could reach up to as high as ∼600 L m−2 h−1 (LMH) at reduced pressures and could be due to the functionalized tips of the nanotubes on the membrane surface resulting from the phase inversion process used for the membrane fabrication. The membranes were characterized by small angle neutron scattering (SANS) to confirm the uniform distribution of the nanopores and the surface morphology of the membranes. Results show that rejection of Cu(II) was better than Pb(II) depending on the surface functionality. Interestingly, these membranes also showed enhanced conductivities in the range of 1.0 × 10−2 S cm−1, the conductivity depending on the type of functionality on the nanotubes, thus confirming the presence of functionalized nanotubes tips on the membrane surface. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43778.