XPS data showed strikingly different surface chemistry for nZVI particles after reacting with B.

High magnetic removal efficiencies were observed for bacteria under the conditions tested, except for Gram-positive ones mixed with nZVI particles followed by addition of Fe 3+. ROS data showed inactivations of bacterial cells could also have resulted from in vivo damage by increased intracellular ROS levels. However, the inactivation of the iron combinations was shown to vary greatly with bacterial types. In general, the culturing and viability tests showed that Fe 2+ had stronger inactivation effects on Gram-negative bacteria, while Fe 3+ inactivated more Gram-positive ones. For nZVI particles of 0.56 mg mL −1, the bacterial growth was promoted when increasing volume was added, more significantly for S. The experimental results revealed that Fe 2+ and Fe 3+ had stronger inactivation effects on all bacteria tested than nZVI under the experimental conditions this effect was especially pronounced for E. The inactivation was determined using an agar plate CFU counting method, and intracellular reactive oxygen species (ROS) was also measured. The iron and microbial mixtures were also subjected to magnetic separation, viability tests by BacLight kit and surface chemistry analysis by X-ray photoelectron microscopy ( XPS). niger and Staphylococcus aureus) and two Gram-negative bacteria ( Pseudomonas fluorescens and Escherichia coli) were subjected to treatment with nZVI particles (0.56 mg mL −1 = 0.01 mol Fe/L), Fe 2+ (0.01 mol L −1) and Fe 3+ (0.01 mol L −1) as well as their combinations with various volumes (10-1000 μL) under aerobic conditions. Two Gram-positive bacteria ( Bacillus subtilis var. This study investigated the biological responses of Gram-positive and Gram-negative bacteria to nZVI particles, Fe 2+ and Fe 3+ ions.

Gram negative and gram positive