MODIFICATION OF CARBON ELECTRODE WITH GRAPHENE/POLYANILINE ELECTROSPUN FIBERS FOR LEAD AND CADMIUM DETECTION

Abstract

The nanoporous fibers of graphene/polyaniline/polystyrene (G/PANI/PS) were fabricated on carbon electrode by electrospinning for the determination of lead (Pb2+) and cadmium (Cd2+). In this study, the parameters controlling the morphology and electrochemical sensitivity of the electrospun G/PANI/PS nanoporous fiber electrodes, such as solvent system, type of carrier polymer and amount of G loading were investigated and optimized. The electrospun G/PANI/PS nanoporous fiber morphology was characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results showed that solvent system was the most important factor affecting the morphology of the electrospun G/PANI/PS nanoporous fibers. The electrochemical sensitivity of the modified electrode was investigated by cyclic voltammetry (CV) using a standard ferri/ferrocyanide [Fe(CN6)3-/4-] redox couple. The current response of electrospun G/PANI/PS nanoporous fibers was higher than unmodified carbon electrode approximately 3 folds. In term of application, the modified electrode was applied for simultaneous Pb2+ and Cd2+ in the presence of bismuth (Bi3+) with square wave anodic stripping voltammetry (SWASV). Under the optimized condition, a linear relationship was found in a range of 10-500 µg L-1 of both Pb2+ and Cd2+. The detection limit (S/N=3) was obtained at 3.30 µg L-1 and 4.43 µg L-1 for Pb2+ and Cd2+, respectively. Furthermore, the modified electrode can be reused for more than ten replicates. This system was successfully applied for the simultaneous determination of Pb2+ and Cd2+ in river water samples, and the results correlate well with the obtained from conventional inductively coupled plasma optical emission spectroscopy (ICP-OES).