Removal of Pb (II), Cd (II), Cu (II) and trichloroethylene from water by Nanofer ZVI

Abstract

Zero-valent iron nanoparticle (Nanofer ZVI) is a new reagent due to its unique structure and properties. Images of scanning electron microscopy/electron dispersive spectroscopy (SEM/EDS), transmission electron microscopy and X-ray diffraction revealed that Nanofer ZVI is stable, reactive and has a unique structure. The particles exhibited a spherical shape, a chain-like structure with a particle size of 20 to 100 nm and a surface area between 25–30 m²g⁻¹. The time interval for particles to agglomerate and settle was between 4–6 h. SEM/EDS Images showed that particle size increased to 2 µm due to agglomeration. Investigation of adsorption and oxidation behavior of Nanofer ZVI used for the removal of Cu(II), Pb(II), Cd(II) ions and trichloroethylene (TCE) from aqueous solutions showed that the optimal pH for Pb(II), Cu(II), Cd(II) and TCE removal were 4.5 and 4.8, 5.0 and 6.5, respectively. Test data were used to form Langmuir and Freundlich isotherms. The maximum contaminant loading was estimated as 270, 170, 110, 130 mg per gram of Nanofer ZVI for Cu(II), Pb(II), Cd(II) and TCE respectively. Removal of metal ions is interpreted in terms of their hydrated ionic radii and their electronegativity. TCE oxidation followed the dechlorination pathway resulting in nonhazardous by-products.

Keywords:

• Freundlich isotherm
• heavy metals
• Langmuir isotherms
• Nanofer ZVI
• TCE

Acknowledgments

The support of the NANOIRON Ltd. (Czech Republic) for supplying the Nanofer ZVI, the technical assistance of TMG group for the use for SEM/EDS and XRD and the accessibility to Environmental Engineering facilities at Concordia University (Montreal) are thankfully acknowledged.