Multifunctional Fe_3O_4@nSiO_2@mSiO_2-Fe core-shell microspheres for highly efficient removal of 1,1,1-trichloro-2,2-bis (4-chlorophenyl)ethane (DDT) from aqueous media

摘要

A novel multifunctional microsphere with an iron oxide-improved mesoporous silica shell and a Fe_3O_4@ SiO_2 core has been successfully prepared by a hydrothermal method and impregnation process. The resulting Fe_3O_4@nSiO_2@mSiO_2-Fe core-shell microspheres are utilized as a catalyst for the removal of 1,1,1-trichloro-2,2-bis(4-chlorophenyl) ethane (DDT) and its derivatives, i.e., 1,1-dichloro-2,2-bis(4-chlorophenyl) ethane (DDD) and 1,1-dichloro-2,2-bis(4-chlorophenyl) ethylene (DDE). The results indicated that the iron oxide nanoparticles were well dispersed on the mesoporous silica shell of Fe_3O_4@nSiO_2@ mSiO_2. DDT, DDD and DDE could be quickly and effectively removed from aqueous media in 60 min, and completely dechlorinated at 350 oC by Fe_3O_4@nSiO_2@mSiO_2-Fe. More importantly, the Fe_3O_4@ nSiO_2@mSiO_2-Fe microspheres were superparamagnetic and could be separated and collected easily and rapidly using a magnet.