Removal of Ni(II) and Cu(II) from aqueous solutions using ‘green’ zero-valent iron nanoparticles produced by oak and mulberry leaf extracts

The production of zero-valent iron nanoparticles, using the extracts from natural products represents green and environmental friendly method. Synthesis of ‘green’ zero-valent nanoparticles (nZVI) using oak and mulberry leaf extracts (OL-nZVI and ML-nZVI) proved to be a promising approach for Ni(II) and Cu(II) removal from aqueous solutions. Characterization of produced green nZVI materials was conducted previously and confirmed the formation of nanosize zero-valent iron particles within the size of 10–30 nm, spherical with minimum agglomeration observed by transmission electron microscopy and scanning electron microscope morphology measurements. Batch experiments revealed that the adsorption kinetics followed pseudo-second order rate equation. The obtained adsorption isotherm data could be well described by the Freundlich model and OL-nZVI showed higher adsorption capacity for Ni(II) removal than ML-nZVI, while ML-nZVI adsorption capacity was higher for Cu(II). In addition, investigation pH effect showed that varying the initial pH value had a great effect on Ni(II) and Cu(II) removal. Adsorbed amount of Ni(II) and Cu(II) increased with the pH increase to pH 7.0 and 8.0. This study indicated that nZVI produced by low cost and non toxic method with oak and mulberry leaf extracts could be used as a new material for remediation of water matrices contaminated with Ni(II) and Cu(II).