Coated nanoscale zero-valent iron and preparation method and application thereof

The invention discloses coated nanoscale zero-valent iron and a preparation method and application thereof. The coated nanoscale zero-valent iron comprises nanoscale zero-valent iron and an inorganiccompound coating the outer surface of the nanoscale zero-valent iron, and the inorganic compound is microsoluble in water. The preparation method comprises the steps: the nanoscale zero-valent iron isdispersed in a precursor solution used for forming the inorganic compound, nanoscale zero-valent iron particles serve as seeds, and an inorganic compound protection layer is formed on the outer surfaces of the nanoscale zero-valent iron particles through heterogeneous nucleation. The coated nanoscale zero-valent iron can be used for removing contaminants from the water in situ. According to the coated nanoscale zero-valent iron, corrosion of the nanoscale zero-valent iron can be relieved while high activity of the nanoscale zero-valent iron of the core is kept, and migration of the nanoscalezero-valent iron is promote