388655 Polyaniline Coated Ethyl Cellulose with Improved Hexavalent Chromium Removal
The adsorption method has been widely used for the removal of toxic hexavalent Chromium (Cr(VI)) from wastewater.[1, 2] Cellulose is considered as a good adsorbent for Cr(VI) removal due to its sustainability and abound active sites. But the lower adsorption capacity and slow removal rate limit its application. Cellulose has been wildly used as the adsorbents for Cr(VI) removal due to its cost effectiveness. Ethyl cellulose (EC) modified with 5.0, 10.0 and 20.0 wt% polyaniline (PANI) (PANI/ECs) were prepared by homogenous mixing the EC and PANI formic acid solutions. The synthesized PANI/ECs demonstrated a superior hexavalent chromium (Cr(VI)) removal performance than pure EC. The Cr(VI) removal percentage increased with increasing the PANI loading. PANI/ECs with 20.0% PANI loading were noticed to remove 2.0 mg/L Cr(VI) completely within 5 min, which is faster than the ethyl cellulose (>1 h). Faster Cr(VI) removal was observed in acidic solutions than in basic solutions. The Cr(VI) removal behavior by PANI/ECs followed the pseudo-second-order kinetic. The adsorption isotherm study demonstrated that the adsorbents follow the Langmuir model with calculated maximum absorption capacities of 19.49, 26.11 and 38.76 mg/g for the 5.0, 10.0, and 20.0 wt% PANI/ECs, respectively, which are much higher than that of EC (12.2 mg/g). The Cr(VI) removal mechanisms explored by FT-IR and XPS involved the reduction of Cr(VI) to Cr(III) by oxidation of PANI and EC.
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 Wang, S.L., Lee, J.F., Reaction mechanism of hexavalent chromium with cellulose. Chem. Eng. J. 2011, 174 (1), 289-295.
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