Polyaniline coated tungsten trioxide as an effective adsorbent for the removal of orange G dye from aqueous media

Abstract

In this work, the core–shell PANI@WO₃ composite was obtained from the reaction of aniline monomer polymerization with WO₃ particles; sodium persulfate was used as an oxidant. Various analytical techniques such as scanning electron microscopy (SEM-EDS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Brunauer–Emmett–Teller (BET), and X-ray photoelectron spectroscopy (XPS) were used to characterize the as-prepared PANI@WO₃ adsorbent, which well confirmed that the WO₃ particles were coated by polyaniline polymer. The PANI@WO₃ composite was tested as an adsorbent to remove reactive orange G (OG) for the first time. pH, adsorbent dose, contact time, initial dye concentration, and temperature were systematically investigated in order to study their effect on the adsorption process. The experimental findings showed that the PANI@WO₃ composite has considerable potential to remove an aqueous OG dye. Langmuir and Freundlich's models were used to analyze the equilibrium isotherms of OG dye adsorption on the PANI@WO₃ composite. As a result, the best correlation of the experimental data was provided by the Langmuir model, and the maximum capacity of adsorption was 226.50 mg g⁻¹. From a thermodynamic point of view, the OG dye adsorption process occurred spontaneously and endothermically. Importantly, PANI@WO₃ still exhibited an excellent adsorption capability after four regeneration cycles, indicating the potential reusability of the PANI@WO₃ composite. These results indicate that the as prepared PANI@WO₃ composite could be employed as an efficient adsorbent and was much better than the parent material adsorption of OG dye.