Sorption of Pb²⁺ from aqueous solution using polyethylene and polyvinylchloride wastes as adsorbents: a comparative study

Abstract

This study gives insight into the sorption potential of Pb²⁺ from aqueous solution using polyethylene and polyvinylchloride wastes as adsorbent. The polymer samples were characterised by X-ray diffraction spectroscopy (XRD), Fourier transform infrared spectroscopy (FTIR), energy dispersive X-ray spectroscopy (EDX), and scanning electron microscopy (SEM) for their morphological features. Kinetic, equilibrium and thermodynamic batch adsorption experiments investigated varying parameters such as: concentration, temperature and time. The SEM images of the polymers revealed irregular small size particles, indicating a high surface area and porosities facilitating sorption. The adsorption studies documented relatively rapid Pb²⁺ uptake by the polymers that are mainly diffusion controlled, with a second order kinetic process. The sorption of Pb²⁺ onto the polymer surfaces was thermodynamically favoured at relatively low temperature (low energy). Thermodynamic studies demonstrated exothermic physi-sorption mechanisms for Polyethylene (PE) and Polyvinylchloride (PVC).

Keywords:

• Polymer
• sorption
• polyethylene
• polyvinylchloride
• adsorbent
• Pb²⁺