Synthesis and characterization of Fe-Al binary oxyhydroxides/MWCNTs nanocomposite for the removal of Cr(VI) from aqueous solution

A facile strategy has been applied for the synthesis of binary metal oxyhydroxide, FeOOH and AlOOH decorated oxidized multiwalled carbon nanotubes (FeOOH/AlOOH/MWCNTs) nanocomposite. The synthesized nanohybrid was characterized by several physico-chemical techniques including X-ray photoelectron spectroscopy (XPS), transmission and scanning electron microscopy (TEM, SEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller measurement (BET) and Raman spectroscopy. The adsorption of Cr(VI) onto FeOOH/AlOOH/MWCNTs was studied as a function of solution pH, reaction time and concentration. The obtained results show that maximum adsorption was occurred at pH 3 within 300 min. The kinetics of Cr(VI) adsorption onto FeOOH/AlOOH/MWCNTs obeyed the pseudo-second order kinetic model. The rate of Cr(VI) diffusion was studied by Weber Morris intraparticle diffusion model and results indicate the film and intraparticle diffusion along with chemisorption (partly) were involved in adsorption process. The adsorption equilibrium data was best fitted with the Langmuir isotherm model and the maximum monolayer adsorption capacity was found to be 60.6 mg/g, which is comparatively higher than oxidized MWCNTs, FeOOH and AlOOH. This study revealed that FeOOH/AlOOH/MWCNTs can be used as a potential adsorbent for the pre-concentration and solidification of the anionic pollutants from the aqueous solution. (C) 2016 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.