Graphene Oxide/Polyaniline/Manganese Oxide Ternary Nanocomposites, Facile Synthesis, Characterization, and Application for Indigo Carmine Removal

Graphene oxide/polyaniline/manganese oxide ternary nanocomposites (GO/PANI/Mn2O3) have been successfully synthesized in one-pot method by in situ chemical oxidative polymerization of aniline in acidic medium using MnO2 as an oxidant. The obtaining nanocomposites have been characterized by transmission electron microscope, Fourier transform infrared, X-ray powder diffraction, and thermogravimetric analysis. The adsorption isotherms of indigo carmine (IC) onto; PANI, GO/PANI, PANI/MnO2, and GO/PANI/Mn2O3 have been evaluated under different adsorption conditions. The adsorption isotherm models of Langmuir, Freundlich, and Temkin were applied and the fit linear was obtained with Langmuir model. It was found that adsorption capacities followed the order: GO/PANI > GO/PANI/Mn2O3 > PANI > PANI/MnO2 with the values of 88.73, 76.40, 60.45 and 22.52 mg/g. Moreover, the kinetics of the adsorption process was investigated and fit linear was obtained with pseudo-second-order model. The adsorption process was exothermic and spontaneous as revealed from the thermodynamic studies.