Polyethylene Glycol 20000-Supported Zero-Valent Iron Nanoparticle for Removal of Pb(II) from Aqueous Solutions: Characteristics, Kinetic and Thermodynamic Studies

The purpose of this work was to investigate the effects of polyethylene glycol 20000 (PEG-20000) as surfactant to support zero-valent iron nanoparticles (ZVIN) for Pb(II) removal. In this study, PEG-20000 supported ZVIN (PEG-ZVIN) were prepared. Their properties were characterized using scanning electron microscopy, transmission electron microscopy, X-ray diffractometry and Brunauer-Emmett-Teller analysis. Then, the material was used to remove Pb(II) from aqueous solutions. The appropriate Fe/PEG ratio (200 mg/L), pH (5.5-6.1) and Pb(II) concentrations (lower than 100 mg/L) for this reaction were identified by bath experiment. Additionally, X-ray photoelectron spectroscopy was used to analyze the reaction mechanism. The data indicated that the developed material had a "shell-core" structure. Subsequently, kinetic models, isotherms and thermodynamic models were used to fit the behavior of the reaction process. These analyses suggested that the process of Pb(II) removal could mainly occur through a spontaneously slow chemical adsorption with valence force through electrons sharing or exchanging between adsorbate and adsorbent. The study indicated that PEG-20000 had a positive effects on the prepared ZVIN, and PEG-ZVIN can be used as a promising candidate for Pb(II) removal from aqueous solutions.