Eco-friendly application of p-cresol–melamine–formaldehyde polymer resin as an ion-exchanger and its electrical and thermal study

Polymer resin p-CMF-II was synthesized by the condensation of p-Cresol (p-C) and melamine (M) with formaldehyde (F) in the presence of 2 M HCl as catalyst with 2:1:3 molar ratio of reacting monomers. The resin was characterized by elemental, IR and NMR spectra. The crystalline and amorphous nature of the polymer was studied by XRD spectra. The morphology was studied by SEM micrographs. The photoluminescence (Pl) of the polymer was studied by Pl spectra. The electrical property of p-CMF-II polymer was measured over a wide range of temperature (313–423 K).The chelating ion-exchange property of this polymer was studied for seven metal ions viz. Fe (III), Cu (II), Ni (II), Co (II), Zn (II), Cd (II) and Pb (II) ions. The chelating ion-exchange study was carried out over a wide range of pH, shaking time and in media of various ionic strengths. Thermal study of the resin was carried out to determine its mode of decomposition and relative thermal stability. The Freeman–Carroll and Sharp–Wentworth methods have been used in the present investigation to calculate thermal activation energy. The different kinetic parameters such as frequency factor (Z), entropy change (ΔS), free energy change (ΔF) and apparent entropy (S*) have been determined using Freeman–Carroll method.