Preparations and characterizations of poly-o-toluidine/multiwalled carbon nanotubes/Sn(iv) tungstate composite ion exchange thin films and their application as a Pb(ii) selective electrode

Abstract

Poly-o-toluidine (POT), poly-o-toluidine (POT)/multiwalled carbon nanotubes (MWCNTs), and poly-o-toluidine (POT)/multiwalled carbon nanotubes (MWCNTs)/Sn(IV) tungstate (ST) thin films were prepared by a solution casting method using polystyrene as a binder. The ion exchange capacity (IEC) of the POT/MWCNTs/ST thin film was found 1.05 meq g⁻¹, which is better than the IEC of pure POT (0.7 meq g⁻¹) and POT/MWCNTs (0.9 meq g⁻¹). The formation of POT, POT/MWCNTs and POT/MWCNTs/ST ion exchange thin films were characterized by scanning electron microscopy (SEM), Energy-Dispersive X-ray (EDX), Fourier transform infra-red (FTIR), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). On the basis of results obtained from the distribution co-efficient (K_d) values, a Pb(II) selective electrode of POT/MWCNTs/ST thin films was fabricated. A linear response in the concentration range of 1 × 10⁻⁹ to 1 × 10⁻¹ M Pb(II) by using the POT/MWCNTs/ST thin film electrode was obtained.