Fig. 3
From: Metal-coordinated sub-10 nm membranes for water purification
Permselectivity of MOPM/PAN membranes. a, b Filtration performance of MOPM/PAN membranes with different coordinated metal ions (a) and MOPM-Fe3+/PAN membranes with varied PA/Fe ratio (b). 100 ppm of Methyl blue (MB, 1.62 × 2.03 nm), Congo red (CR, 1.10 × 2.20 nm), Alcian blue (AB, 1.42 × 2.20 nm), Rose Bengal (RB, 1.06 × 1.08 nm) and Orange GII (OG, 0.74 × 1.07 nm) solution as feed. c Ultraviolet-visible spectra of Congo red in feed, retentate, and filtrate. PA/Fe ratio = 1:7. Inset in c: Digital photo images of feed (Fe), retentate (Re) and filtrate (Fi) (top left) and molecular structure of Congo red (bottom right). d Ultraviolet-visible absorption spectra of graphene oxide quantum dots (GQDs) in feed, retentate, and filtrate. PA/Fe ratio = 1:0.5. Inset in d: Size distribution of GQDs (top left), digital photo images of feed (Fe) and filtrate (Fi) (top right) and TEM image of GQDs (bottom). Scale bar: 10 nm. e Water permeance of MOPM-Fe3+/PAN membranes with different layer number of MOPM-Fe3+. PA/Fe ratio = 1:7. Red line was the best exponential fit. Inset in e: Mass transport resistance as a function of thickness for MOPM-Fe3+/PAN membranes with different skin layer thicknesses. Red line was the best linear fit. f Filtration performance of state-of-the-art polymeric membranes for water purification in literatures. Error bars represent standard deviations for 3 measurements
