If nZVI is meant to be equivalent with "metallic Fe nanoparticles" then the anwer to the questin as given in th question headline is certainly "yes". This would apply to both iron cores in iron-iron oxide core shell particles as well as pure iron particles (not so easy to have, see DOI:10.1002/pssb.200945607 for example).
As to 'magnetic recovery', does that relate to "extraction from a dispersion with a magnet"? This would not be doable in the case of the particles in the paper I am alluding to since these particles were prepared such as to reside on a substrate.