Effect of polyaniline particle size on the chromate adsorption from aqueous electrolyte.

In this contribution, we report the investigation on removing of the oxochromium (VI), a hazardous species, using HCl-doped polyaniline (PAni-HCl) as adsorbent versus particles size. PAni-HCl has been successfully elaborated by conventional oxidative chemical method in the temperature range (0–3 °C). The recovered powder was milled and sieved into size ranges of < 50, 50–63, 125–160 and > 200 µm. The batch adsorption experiments were performed at 25 °C, using 250 mg of PAni-HCl dispersed in 250 mL of Cr(VI) aqueous solution (250 mg L−1). The Cr(VI) uptake was significantly influenced by both the particle size and contact time. Smaller particle sizes allow a quick initial adsorption and high removal efficiency (~100%). The kinetics of the Cr(VI) adsorption follow the pseudo-second-order model. A good correlation was demonstrated between the removal chromium (VI) properties (Qe,exp, k2 and τ(%)) and the (normalized) mean diameter ratio. [ABSTRACT FROM AUTHOR]