Vinyl pyridinium polymeric ionic liquid functionalized carbon nanotube composites as adsorbent for chromium(VI) in aqueous solution

Vinyl-pyridinium polymeric ionic liquids (PILs) cations were synthesized and used to prepare polymeric ionic liquids/multiwalled carbon nanotubes (PIL/MWCNT) composites. The as-synthesized PILs and composites were characterized by infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), thermal analysis (TGA/DSC), scanning electron microscopy/energy-dispersive spectroscopy (SEM/EDS), transmission electron microscopy (TEM). Thermal studies showed that PIL/MWCNT composites are more stable than their individual components and are insoluble in water and other non-polar solvents, but soluble in some polar-aprotic solvents. The potential of the PIL/MWCNT as adsorbent for Cr(VI) ion in aqueous solution were evaluated. The PIL/MWCNT composites showed maximum adsorption capacity of 37% within 12 h of agitation and the adsorption trends are in the order PIL5/MWCNT > PIL6/MWCNT > PIL3/MWCNT.