Synthesis of PANI/AlOOH composite for Cr(VI) adsorption and reduction from aqueous solutions

In this study, polyaniline rafted to the surface of AlOOH (PANI/AlOOH) composites were successfully synthesized and applied for chromium (Cr(VI)) adsorption from aqueous solutions. Cr(VI) adsorption isotherms were described by Langmuir model well and the maximum adsorption capacity was 66.77 mg/g at pH=5 and T=298 K. Cr(VI) adsorption was attributed to chemisorption and outer-sphere surface complexation. The interaction mechanism was further investigated by Fourier transform infrared spectroscopy, transmission electron microscopy-energy dispersive spectroscopy and X-ray photoelectron spectroscopy techniques, and the results suggested the partially reduction of Cr(VI) to Cr(III). Cr(VI) removal was mainly related with the electrostatic attraction and chelation of different Cr(VI)/Cr(III) species with protonated nitrogen-containing functional groups (-NH+, -NH-) on PANI/AlOOH.