PROCESS FOR PREPARING MAGNETITE OR MAGHEMITE NANOPARTICLES WITH CONTROLLED SIZE USING MILD CONDITIONS

摘要

The invention relates to an improved process for preparing magnetite or maghemite nanoparticles with controlled size using mild conditions. The process according to the invention comprises coprecipitation of Fe²⁺ and Fe³⁺ ions in an aqueous solution under mild alkaline conditions in a pH range from 8 to 12 and a temperature from 15 to 40°C. In a more specific embodiment of the process according to the present invention, the coprecipitation is effected by providing an aqueous reaction medium comprising deionized water set to the desired pH and continuously adding a mixed aqueous solution of Fe²⁺ and Fe³⁺ salts to the reaction medium.