Synergetic effect between zeolite 5 A and maghemite nanoparticles for fast lead uptake from the Peruvian river Cumbaza: Study of surface adsorption mechanism using X-ray photoelectron spectroscopy

Abstract

A novel magnetic composite of zeolite 5A and maghemite nanoparticles has been synthesized at 300 K and its lead removal properties from the Peruvian river Cumbaza were systematically studied. Its kinetic adsorption properties were investigated, and a fast equilibrium time of 15 min was achieved with 97% of removal and an adsorbent dose of 0.5 g L−1. A 100% Pb removal efficiency was reached by increasing the adsorbent dose to 1.0 g L−1, which concomitantly also removed iron species from the river aliquots. During the kinetic tests, the optimum pH was from 6.5 to 7.5, showing that no chemical reactant alteration was required to achieve a remarkable efficiency for the magnetic composite. The kinetic adsorption behavior matched well with the pseudo-first and second-order models. Post-adsorption analysis confirmed the presence of lead in all the samples. The combined results also demonstrated a synergetic response between lead and both adsorbent phases. The adsorption mechanism was governed by three steps, including inner surface complexation between lead species and maghemite, followed by lead cationic exchange between calcium-bulk and sodium-surface from zeolite 5A. Hence, this novel magnetic adsorbent exhibits a high lead removal efficiency, and it is easy-to-handle separation properties in real effluents.