A novel green synthesis of zero valent iron nanoparticles (nZVI) using walnut green skin: characterisation, catalytic degradation and toxicity studies

ABSTRACT

In the present study, green synthesised nanoparticles were used to activate persulphate and used for the oxidation of metronidazole (MTZ). In the process of green synthesis, the walnut green skin was used for the synthesis of zero-valent iron (nZVI) particles. These nanoparticles’ FESEM images revealed that they were spherical-shaped nanoparticles with a diameter ranging from 18 to 72 nm. Also, the FTIR spectra indicated the functional groups of polyphenols on the surfaces of the nZVI nanoparticles. Moreover, the XRD pattern illustrated that the synthesised particles possessed a high crystalline quality structure. According to the results, under the optimum conditions, the removal efficiency of the process in degradation of MTZ was 90.3%. LC-MS chromatography showed 7 by-products with reduced toxicity in the reactor outputs. It was found that the green synthesised nZVI had a good effect on the activation of the PS and the PS/nZVI process had a high ability in degradation of MTZ from aqueous solutions.

KEYWORDS:

• Green synthesis
• persulphate
• nZVI
• metronidazole
• walnut green skin
• toxicity test

Acknowledgments

The present paper is the result of a master’s thesis in the field of environmental health engineering approved by the Vice-Chancellor for Education of Ardabil University of Medical Sciences and Health Services with a design code of 2.9507, which is hereby appreciated. It is also mentioned that this article is derived from the preprint paper, herewith we thank the Research Square.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the Ardabil University of Medical Sciences.