Understanding the morphology of MWCNT/PES mixed-matrix membranes using SANS: interpretation and rejection performance

We describe the relationship between the morphology and rejection performance by the mixed-matrix membranes as a unique class of high water flux nanofiltration membranes comprising polyethersulfone/functionalized multiwalled carbon nanotubes (PES/f-MWCNTs). These membranes contain aligned MWCNTs uniformly distributed inside a PES matrix prepared using conventional phase-inversion technique. The small-angle neutron scattering analysis confirmed the high porosity and uniformity among of the pores of CNTs in the membranes. The frictionless water transport from vertically oriented f-MWCNTs were verified to facilitate remarkable enhancement in the water flux through the membranes. The water transportation speed, as well as rejection, of selected heavy metals increases nearly about 3 times and 2-3.5 times, respectively, than the pristine PES membrane, depending upon CNTs loading. Low working pressure and good retention properties make these membranes to be an ideal for the application of highly efficient filtration units.