Facile elaboration of arginine-functionalized PANI@graphitic carbon nitride for efficient removal of hexavalent chromium

In this current study, an arginine-functionalized polyaniline@g-C3N4 composite was designed by an interfacial polymerization reaction; hence this composite has been applied as adsorbent material for the adsorption of hexavalent chromium Cr(VI) ions from solution. The as-developed composite's surface features were analyzed by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), X-ray energy dispersive spectroscopy (EDS), porosity and point of zero charge (PZC). Batch experiments were employed to study the adsorbent dosage, initial Cr(VI) concentration, contact time, pH's solution and temperature effects. The results showed that the highest adsorption capacity was obtained to be 204.04 mg.g−1 at pH = 2. The experimental data showed that the adsorption of Cr(VI) on Arg-functionalized PANI@g-C3N4 were well correlate with the pseudo-second order kinetic model and Freundlich isotherm models. The calculated thermodynamic parameters Gibb's free energy (∆G°), enthalpy (∆H°) and entropy (∆S°) suggested that the adsorption was spontaneous and exothermic. The co-interfering ions was also assessed. We further evaluated that Arg-functionalized PANI@g-C3N4 could be easily regenerated with NaOH solution and successfully reused for the removal of Cr(VI) from aqueous solution. These findings showed that the synthesized Arg-functionalized PANI@g-C3N4 had a powerful potential for treating wastewater containing Cr(VI).