Adsorption Studies of Cd(II) and Zn(II) onto Polypyrrole/Sb₂O₃ Nanocomposite: Kinetics, Equilibrium, and Thermodynamics

Introduction: Heavy metal ions are very toxic to public and personal health. A special polypyrrole with environmental stability and reusability was used to remove metal ions from aqueous solution. In this work, a new polypyrrole (PPy/Sb۲O۳) nanosorbent was successfully synthesized in aqueous solution. Methods: The purpose of this research was to investigate the adsorption properties of polypyrrole nanocomposites for the removal of Cd(II) and Zn(II) from aqueous solution. Batch various factors affecting the adsorption equilibrium were investigated in detail. Also, different models (isotherm, kinetic, and thermodynamic) were compared to describe the adsorption phenomenon. Results: The adsorption isotherms for Cd(II) and Zn(II) were well fitted by the Langmuir model with a maximum monolayer capacity of ۱۷.۳۳ and ۱۵.۳۶۱ mg/g, respectively, for Cd (II) and Zn (II) ions. Moreover, thermodynamic analysis shows the endothermic nature and spontaneity of the adsorption process with increasing entropy in PPy-PVA/Sb۲O۳. From the kinetic results, it was concluded that the pseudo-second-order kinetic model is the best in describing the adsorption process for Cd (II) and Zn (II). The consistency of the experimental qe with the qe calculated from the pseudo-second-order kinetic model indicated that the adsorption of Cd(II) and Zn(II) on PPy-PVA/Sb۲O۳ is probably controlled by chemisorption. Conclusion: This study shows that polypyrrole and its nanocomposites have a potential for use as effective adsorbents due to their ease of synthesis, low cost, and regeneration efficiency for the removal of heavy metal ions from aqueous solutions.

کلیدواژه ها:

Polypyrrole ، Adsorption ، Nanocomposite ، Isotherm ، Thermodynamic