Reactivity of nZVI increased linearly with nZVI concentration above 10 g/L, but was non-linear below 10 g/L.

nZVI reactivity with PCE is more sensitive to solution redox potential than solution pH.

Mass transfer limits the reactivity of emplaced nZVI under typical groundwater flow velocity.

Lowering pH increases H₂ evolution from nZVI more than reactivity with PCE.

Design of nZVI remediation strategies should consider mass loading and flow velocity on performance and lifetime.