Bactericidal Effect of Zero-Valent Iron Nanoparticles on Escherichia coli

Abstract

Zero-valent iron nanoparticles (nano-Fe0) in aqueous solution rapidly inactivated Escherichia coli (E. coli). A strong bactericidal effect of nano-Fe0 was found under deaerated conditions, with a linear correlation between log inactivation and nano-Fe0 dose (0.82 log inactivation / mg/L nano-Fe0 · hr). The inactivation of E. coli under air saturation required much higher nano-Fe0 doses due to the corrosion and surface oxidation of nano-Fe0 by dissolved oxygen. Significant physical disruption of the cell membranes was observed in E. coli exposed to nano-Fe0, which may have caused the inactivation, or enhanced the biocidal effects of dissolved iron. The reaction of Fe(II) with intracellular oxygen or hydrogen peroxide also may have induced oxidative stress by producing reactive oxygen species. The bactericidal effect of nano-Fe0 was a unique property of nano-Fe0, which was not observed in other types of iron-based compounds.

Pharmaceutical removal from water with iron- or manganese-based technologies: A review

“…One possible explanation is the physical disruption of cell membranes by nZVI. It can also enhance the biocide effect of Fe (Lee et al, 2008). Toxicity to microorganisms is also observed with other Fe-or Mn-containing nanoparticles (Bellusci et al, 2014).…”

The mechanism for bacteriophage f2 removal by nanoscale zero-valent iron

“…As reported, the removal of bacteriophage f2 by NZVI involved the generation of intermediates, such as Fe 2þ , Fe 3þ , reactive oxygen species (Fe(IV), $OH and $O 2 À ), originated from the Fe-participated reactions (Lee et al, 2008b;Kim et al, 2011). In order to investigate which one of the intermediates played a dominant role in the bacteriophage f2 removal, a series of experiments were carried out as follows.…”

“…It indicated that Fe(III) made little contribution to the removal of bacteriophage f2. It is likely that limited solubility of Fe(III) made the removal of virus be difficult under neutral pH circumstances (Lee et al, 2008b;Keenan and Sedlak, 2008).…”

“…In the Fe(II) and oxygen system, superoxide radical and hydrogen peroxide can be generated from the reaction of Fe(II) and oxygen through one-electron transfer (reactions 2 and 3) (Lee et al, 2008b;Kim et al, 2011). And hydroxyl radical was subsequently yielded through Fenton reaction (reaction 4).…”

“…However, it's reported that the removal mechanisms of bacteria and virus were totally different. According to the published researches, the removal efficiency for E. coli was higher under anaerobic conditions than that under aerobic conditions, indicating the mechanism was mainly attributed to the direct interaction between NZVI and bacteria (Lee et al, 2008b;Kim et al, 2010b). Contrary to E. coli, the inactivation efficiency of MS2 by NZVI was much higher in the presence of oxygen, suggesting the reactive oxygen species (ROS) generated during the oxidation of NZVI was responsible for the virus removal (Kim et al, 2011).…”