Use of Electrochemical Quartz Crystal Microbalance Technique to Track Electrochemically Assisted Removal of Heavy Metals from Aqueous Solutions by Cation-Exchange Composite Polypyrrole-Modified Electrodes

Abstract

The removal of heavy metals from aqueous solutions is of great importance. A new method of electrochemically assisted removal of heavy metal ions from aqueous solutions is presented. Composite polypyrrole films with cation-exchange properties were synthesized on the electrode surface. The uptake of cations by the polymer film is based on the counterion effect and occurs without any change in their oxidation state. The incorporation of cations and their preconcentration inside the polymer matrix take place during the negative potential step. The regeneration of the membrane and the release of accumulated cations occur upon the potential reversal step. No chemicals for the regeneration of the membrane are required. The use of the electrochemical quartz crystal microbalance (EQCM) technique allowed us to characterize the ion dynamics in composite polymer films and to trackin situthe incorporation and release of heavy metal cations such as Pb+2, Cd+2, and Ni+2.