Peer-Reviewed Journal Details
Mandatory Fields
Farrell, ST;Breslin, CB
2004
September
Environmental Science and Technology
Reduction of Cr(VI) at a polyaniline film: Influence of film thickness and oxidation state
Published
55 ()
Optional Fields
HEXAVALENT CHROMIUM AQUEOUS-SOLUTIONS CR-VI PIEZOELECTRIC SENSOR CONDUCTING POLYMER MODIFIED ELECTRODE POLYPYRROLE KINETICS METAL MECHANISM
38
4671
4676
Hexavalent chromium [Cr(VI)] is highly toxic, carcinogenic, and mutagenic to living organisms. In this paper, the reduction of Cr(VI) to the much less toxic trivalent state [Cr(III)] was studied at polyaniline films grown to different thickness. Much higher rates of Cr(VI) reduction were observed for the "thick" polyaniline films. This was explained in terms of the morphology of the polymer and the higher surface area of polymer in contact with the Cr(VI) solution. For "thin" polyaniline films, the Cr(VI) reduction reaction was found to obey pseudo-first-order kinetics for the duration of exposure. However, in the case of thick polyaniline layers,the Cr(VI) reduction reaction followed a two-stage process, with each stage obeying pseudo-first-order kinetics. This was explained in terms of oxidation of the polymer from the leucoemeraldine to the emeraldine state and then further oxidation of the polymer from the emeraldine to the pernigraniline state. Much higher rates of Cr(VI) reduction were observed on oxidation of the polymer from the leucoemeraldine to the emeraldine state.
WASHINGTON
0013-936X
10.1021/es0498585
Grant Details