Adsorption of Cu(II), Ni(II) and Pb(II) ions onto polyamine-polyurea polymer modified with pyromellitic dianhydride: kinetic, isotherm and thermodynamic studies

Abstract

In this study, a polyamine-polyurea polymer modified with pyromellitic dianhydride was used for batch adsorption of Cu(II), Ni(II), and Pb(II) ions to examine the effects of parameters such as pH, contact time, amount of adsorbent, temperature, and initial concentration of heavy metals. The optimum pH value was found to be 6.0 and the contact time required to reach equilibrium was 120 min. Adsorption kinetics, thermodynamics and equilibrium were analysed. The adsorptions of the metal ions were found to comply with the Langmuir isotherm equation and the pseudo-second-order kinetic model. The maximum monolayer adsorption capacity of the modified polymer for Cu(II), Ni(II), and Pb(II) ions was found to be 73.5, 81.3, and 109.9 mg g⁻¹, respectively. Adsorption mechanism studies of the intraparticle diffusion model showed that surface sorption and intraparticle diffusion contribute to the rate-limiting step. Thermodynamic parameters showed the adsorption processes for all metals with the polymer have an endothermic, irreversible and spontaneous nature.

Keywords:

• Heavy metals
• Adsorption
• Polyamine-polyurea polymer
• Modification
• Pyromellitic dianhydride
• Isotherms
• Kinetics
• Thermodynamics

Acknowledgement

This work was supported by Sakarya University Research Fund with project number 2012-50-02-028.