Removal of Cd(II) and Co(II) ions from aqueous solutions by polypyrrole particles: Kinetics, equilibrium and thermodynamics

In this work, electroactive polypyrrole (PPy) particles obtained by oxidative polymerization of pyrrole in acetonitrile were used to remove cadmium and cobalt ions from aqueous solutions. FTIR, cyclic voltammetry (CV), X-ray diffraction (XRD), atomic force microscopy (AFM) and conductivity measurements were applied to analyze cadmium and cobalt interaction with the synthesized polymer. Kinetic data were properly fitted with the pseudo-first-order kinetic model. The equilibrium data fitted very well to the Langmuir model with a maximum monolayer capacity of 71.4 and 70.04 mg/g, respectively for cadmium(II) and cobalt(II) ions. The metals uptake increases with an increase in solution temperature. Indeed we noted that, the polypyrrole particles plays two beneficial roles: (1) to remove heavy metals from aqueous solutions and (2) this latter served as doping agent for the polypyrrole particles.