  The objective of this investigation is to synthesize and investigate
zero-valent iron (ZVI) nanoparticles (NPs) for bioremediation applications. The
ZVI-NPs were fabricated by chemical reduction using a ferrous salt solution
with poly(N-vinylpyrrolidone) (PVP), used as a stabilizer. The synthesis was
conducted with and without ultrasonic treatment. The ZVI NPs were fabricated
and characterized using scanning electron microscopy (SEM), transmission
electron microscopy (TEM), X-ray powder diffraction (XRD) analysis, and Fourier
Transform Infrared Spectroscopy (FTIR). Experimental observations demonstrate
that depending on synthesis conditions and coordination of stabilizers, NPs
with different morphologies are formed. Colloidal solutions of the synthesized
NPs were used in antimicrobial activity tests and biofilm formation assays for
nine different control microorganisms: Escherichia coli (ATCC 25922),
Pseudomonas aeruginosa (ATCC 15692), Enterococcus faecalis (ATCC 29122),
Klebsiella pneumoniae (laboratory isolates), Proteus vulgaris (laboratory
isolates), Staphylococcus aureus (ATCC 29213), Bacillus cereus (DSMZ 4312),
Bacillus subtilis (ATCC 6633), and Candida albicans (ATCC 10231). All control
strains did not show antibacterial effect against PVP-stabilized ZVI NPs
synthesized without ultrasonic treatment. However, biofilm results show that
the highest absorbance values of the micro-organisms were tested in control
wells.
