Synthesis of Polyaniline/Graphene Composites and Its Application in Detecting Heavy Metal Ions

Polyaniline/graphene nanocomposite (PANI/G) was synthesized by an in situ polymerization procedure. The microstructure of PANI/G was characterized to be a mixture of PANI nanowires and graphene sheets by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Energy Dispersive X-Ray Fluoresence Spectrometer (EDX). PANI/G was used to modify glassy carbon electrodes to detect heavy metal ions in aqueous phase by the electrochemical methods. To make a contrast, Polyaniline (PANI) modified glassy-carbon electrode was also used to detect the mixed heavy metal ions including Cd²⁺, Pb²⁺, Cu²⁺ by Anodic Stripping Voltammetry (ASV). Results showed that PANI/G exhibiting higher sensitivity in detecting heavy metal ions than PANI and showing a great selectivity towards Pb²⁺. Then the electrochemical behavior in detecting Pb²⁺ by PANI/G was investigated. The detection limit for Pb²⁺ was 10^-8mol/L, being lower than that of national sanitary standard for drinking water.