The method of preparing a nano-magnetic particles

The present invention discloses a method for preparing magnetic nanoparticles of iron salt after mixing ammonia aqueous ethanol, and nanoscale, and then adjusting the pH, after washing by centrifugation, to obtain surface-modified iron microspheres; then to ultrasonic dispersion water, adding ferric chloride solution was stirred, washed by centrifugation and redispersed in water; and then under ultrasonic conditions, the microspheres are added the iron solution polydopamine infiltration, then centrifuged, so that the generated surface of a microsphere iron nanoparticle layer; iron microspheres dispersed in nitric acid solution, under stirring, the addition of a dispersant, citric acid, deionized water, and ultrasonic dispersion was centrifuged deposition cycle cleaning method, the microsphere composite remove reaction residue, i.e. to obtain magnetic nanoparticles. The present invention provides magnetic nanoparticles used in sewage treatment, good effect, the magnetic nanoparticles can be used repeatedly and demagnetized easily dispersed, high recovery efficiency and prolong the service life of the magnetic nanoparticles, reduced sewage treatment the cost of.