Removal of Cr(VI) using polyacrylonitrile/ferrous chloride composite nanofibers

Considering economic feasibility and technical effectiveness, polyacrylonitrile/ferrous chloride composite nanofibers prepared by electrospinning was used to remove the Cr(VI). Maximum removal of Cr(VI) by composite nanofibers was observed in weakly acidic environment. The analysis of the reaction kinetics revealed that the adsorption behavior seemed to follow pseudo-second-order kinetic model. Through calculating thermodynamic parameter, the adsorption reaction was proved to be an exothermic and chemical process. The PAN...Fe1-xCrx(OH)(3) and PAN...Fe1-xCrx(OH)(x) were proposed to be formed after the redox reaction was taken place. The interactive effects of coexisting ions of different metal ions like arsenic, lead and cadmium were also explored for practical consideration. The presence of these metal ions apparently decreased the efficiency of the Cr(VI) adsorption. In addition, the interactive inhibition of arsenic was more significant than other coexisting ions. It was suspected that the valence state (e.g., NO3-, SO42-, Cl-, Ca-2 +/-, Na-+/- and Mg-2 +/-) may play a crucial role during the reaction. Due to the strong electrostatic attraction, anions had the more significant attenuating effect than cations. This study is helpful not only for doping design of iron oxide nanofibers but also for practical application during advanced wastewater treatment. (C) 2016 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.