Kinetic Study of the Cd-Biopolyelectrolyte Complexes Formation Using Square Wave Stripping Voltammetry

In this work an electrochemical methodology was developed to follow the association kinetics between a heavy metals and two different biopolymers, BP (corn gum and chitosan). This type of interaction is a key factor in the removal of metal ions contained in aqueous media at low concentrations. An aqueous solution with ppm of cadmium was used as a model to evaluate the kinetics of formation of the Cd-BP complex. The method selected for the quantification of cadmium was the square wave stripping voltammetry (SWSV). The experiment was carried out using a Britton-Robinson solution as a support electrolyte at pH 4.5, vitreous carbon as a working electrode, Calomel as a reference electrode, and graphite as a counter electrode. The initial concentration of Cd (II) solution was 10 mg/L. The concentration changes were recorded during 590 s. The kinetic models chosen to identify the reaction mechanism of the complex formation process were reversible first order and pseudo first order.