Conducting macroporous polyaniline/poly(vinyl alcohol) aerogels for the removal of chromium(VI) from aqueous media

Extensive research has been focused on the removal of various pollutants from wastewaters. Hexavalent chromium Cr(VI) is of special concern as it is a known carcinogen. In the present study, macroporous polyaniline/poly(vinyl alcohol) aerogel was applied as a promising material form which can act as both adsorbent and reductant for Cr(VI) in aqueous solutions. The removal of Cr(VI) was assessed by monitoring the decrease in optical absorption with UV-visible absorption spectroscopy. The effect of different parameters, such as the initial Cr(VI) concentration, contact time, and the adsorbent dose, on the removal process has been studied. The intraparticle diffusion model was found to characterize the adsorption process well, but Freundlich isotherm best fits the adsorption isotherm data. Investigation of the substrate regeneration revealed that polyaniline-based aerogel can be reused for the removal of Cr(VI) with good efficiency. The maximum adsorption capacity of composite aerogel reached 41.2 mg g(-1), which is one of the best results reported in the literature. The conductivity and electroactivity of the material may subsequently be used in the design of intelligent adsorbents when the adsorption/desorption could be controlled by the applied electrical potential.