Đỗ Trà Hương, Dương Thị Tú Anh

   The removal of  Cr(VI) from aqueous solution by magnetic nanoparticles prepared and impregnated        on to tea waste (TW- Fe3O4) from agriculture biomass was investigated. Magnetic nanoparticles (Fe3O4) wereprepared by chemical precipitation of a Fe²⁺ and Fe³⁺ salts from aqueous solution by ammonia solution. The crystal structure of the materials was determined by X-ray diffraction spectrum. Surface characterictics of the materials were examined using scanning electron microscope SEM, transmission electron microscope (TEM) and Fourier Transform-Infrared Spectroscopy (FT-IR).  Keywords:  Adsorption; tea waste; materials; magnetic; nanoparticles.