Adsorption studies of Orange II onto polyaniline/bentonite nanocomposite.

Modification of bentonite is essential for the adsorption of anionic dyes, as its negative surface charge. In this study, polyaniline/bentonite (PAni-Bent) nanocomposite was synthesized by in-situ intercalative polymerization technique and used to remove anionic dye Orange II (ORII) from synthetic wastewater. Its structure was confirmed by X-ray diffraction (XRD), scanning electron microscopy, Fourier-transform infrared spectra and Brunauer-Emmett-Teller specific surface area measurements. The adsorption behaviours of PAni-Bent towards ORII in the single anionic dye wastewater, the cationic/anionic mixture dye wastewater, with or without salt or surfactant, were investigated principally. The results show that cetyl trimethyl ammonium bromide have an obviously suppressing effect on dye removal in the MB/ORII mixture system. The Langmuir and Temkin isotherm models described the adsorption process better than Freundlich or Dubinin-Radushkevich (D-R) model, and the pseudo-second-order and Boyd kinetic models fit better with the experimental data. Considering all these unique characteristics, PAni-Bent can be considered as effective adsorbent material for potential removal of dye from aqueous solution in industry.