Aquatic and terrestrial weed mediated synthesis of iron nanoparticles for possible application in wastewater remediation

The present study was aimed to utilize the aquatic and terrestrial weeds such as Eichhornia crassipes, Lantana camara and Mimosa pudica for the synthesis of iron nanoparticles. The formation of iron nanoparticles was characterized using UV–vis spectroscopy, Dynamic light scattering, Field emission scanning electron microscopy, and Energy dispersive x-ray analysis, Transmission electron microscopy, X-ray diffraction and Fourier transform infrared spectroscopy. The UV–vis spectra showed a disappearance of the peak in case of synthesized iron nanoparticles which confirmed the formation of iron nanoparticles. The phase analysis using X-ray diffraction revealed the amorphous nature of iron nanoparticles. The dynamic light scattering confirmed 40–60 nm, 50–80 nm and 65–230 nm size distribution for Eichhornia crassipes, Lantana camara and Mimosa pudica synthesized iron nanoparticles respectively. The Transmission electron microscopy micrographs indicated the prominent capping layer of polyphenols around the nanoparticles. The reactivity of synthesized iron nanoparticles for nitrate and phosphate removal was also evaluated on real collected samples of dairy wastewater. A control experiment exhibited that chemically synthesized iron nanoparticles removed 85.27% of nitrate, while Eichhornia crassipes, Lantana camara and Mimosa pudica mediated iron nanoparticles showed 74.52%, 71.12% and 65.23% of nitrate removal respectively. The nitrate was more efficiently removed than the phosphate. The stability of extract based nanoparticles was higher than the chemically synthesized iron nanoparticles. The findings of the present work revealed that weeds which are treated as waste and worthless have very high potential to synthesize iron nanoparticles. Further, these as prepared iron nanoparticles can be applied in treating nitrate and phosphate pollutants present in eutrophic wastewater.