Reducing potential of zero-valent iron nanoparticles is very high, therefore nZVI can reduce another matters contained in the water like dissolved oxygen, sulphates, nitrates, etc. NZVI reacts with oxygen dissolved in water:
Fe0 + 1/2 O2 + 2 H+ ↔ Fe2+ + H2O
Oxygen present in the environment is reduced which leads to decrease of redox potential and reduction of monitored contaminants proceeds.
The oxidation of Fe(0) nanoparticles stored in water is another important process: zero-valent iron nanoparticles tend to significantly affect the redox potential, reduce water to hydrogen and hydroxide and increase pH.
Fe0 + 2 H+ ↔ Fe2+ + H2
Oxidation (corrosion) of nanoparticles and decrease of reactivity is an undesirable phenomenon in the time since slurry production untill its application. This side effect can be suppressed by manufacturing of a fresh slurry from a dry nanopowder on site or by a just in-time delivery. Please see details of nZVI slurry ageing.