Synthesis of graphene/Fe3O4/polyaniline nanocomposite for simultaneous removal of a binary mixture of malachite green cationic dye and acid red 1 anionic dye from aqueous solutions

Abstract

This work demonstrates the effective removal of the binary combination of Malachite Green (MG) and Acid Red 1 (AR1) dyes using a graphene/Fe3O4/polyaniline (Gr/Fe3O4/PANI) nanocomposite. Various methods, such as FTIR, XRD, SEM, TEM, VSM, and UV–Vis, were employed to investigate the morphological and structural characteristics of the adsorbent. The response surface methodology-central composite design was used to assess the influence of parameters including solution pH, contact time, concentration of each dye, and adsorbent mass. The pH = 6.5, concentration for each dye of 16 mg L−1, adsorbent mass 30 mg, and contact time of 24 min were shown to be optimal for MG and AR1 dye adsorption. The isotherm models indicate that the dye removal process follows the Langmuir, and the adsorption capacity of the synthesized adsorbent for MG and AR1 was 196.10 and 150.27 mg g−1, respectively. The analysis of the collected kinetic models revealed that the quasi-quadratic kinetic model best fits the experimental results. Also, the thermodynamic values obtained from the data showed that the elimination process is endothermic and spontaneous. Finally, due to the high adsorption capacity of the synthesized adsorbent, the adsorbent recovery capability in 5 consecutive cycles for mixing both dyes was investigated.