Efficient removal of As (III) by calcined green synthesized bimetallic Fe/Pd nanoparticles based on adsorption and oxidation

Arsenic pollution has become one of main threats to global drinking water safety and urgently needs to be cost effectively remediated. Here, calcined green bimetallic Fe/Pd nanoparticles (Calcined-Fe/Pd NPs) were synthesized using a eucalyptus leaf extract and successfully applied for As (III) removal from wastewaters, achieving a 100% removal efficiency under optimal experiment conditions. To better understand the highly effective removal mechanism, Calcined-Fe/Pd NPs were characterized by various techniques. While Transmission Electron Microscope (TEM), Energy Dispersive Spectrometer (EDS) and X-ray diffraction (XRD) indicated that As (III) adsorption was substantial; both X-ray photoelectron spectroscopy (XPS) and ion chromatography-atomic fluorescence spectrometer (IC-AFS) indicted that during adsorption As (III) was oxidized to As (V). Kinetic fitting of results revealed that adsorption obeyed a pseudo-second-order model (R-2 = 0.986) and Langmuir isotherm (R-2 = 0.994), whereas oxidation best fit a pseudo first order model (R-2 = 0.927). Thus, an overall mechanism for As (III) removal based on adsorption and oxidation was proposed. The utility of practically using calcined green synthesized bimetallic Fe/Pd nanoparticles was also validated by the removal of >90% As (III) from drinking water. (c) 2020 Elsevier Ltd. All rights reserved.

Automated summary

Arsenic pollution poses a major threat to global drinking water safety, and the use of Calcined-Fe/Pd NPs has been shown to effectively remove As (III) from wastewater. Characterization techniques revealed substantial As (III) adsorption and oxidation to As (V), leading to a proposed mechanism for arsenic removal based on adsorption and oxidation. Practical application demonstrated over 90% removal of As (III) from drinking water, validating the effectiveness of this method.