The Synthesized And Applied Research Of Cobalt Ferrite Composite Nanomaterials

Cobalt ferrite is a typical soft-magneticspinel-type ferrite,and the corresponding nanomaterials possess excellent physical properties and good chemical stability.In this paper,the preparation and materials properties of cobalt ferrite and its composites are studied.The applications in dyes and metal ions adsorption as well as microwave absorption are discussed in detail,and the physical mechanism is elaborated.In order to improve the adsorption and absorption properties of cobalt ferrite nanomaterials,the performance of the organicswith special functional groups and two-dimensional graphene nanocomposites are studied.Besides,the enhanced mechanism on properties of the nanocomposite is explained.The specific contents are divided into the following two parts:1.Adsorption of dye and metal ions on PA/CFO nanocomposites.CoFe2O4(abbreviated as CFO)and CFO-phytic acid(PA)nanocomposites(PA/CFO)are prepared by a simple microwave hydrothermal method.The properties of the as-synthesied samples are characterized by XRD,Raman,FTIR,SEM and TEM.The results show that the addition of PA inhibits the growth of CFO nanoparticles,affects the morphology of CFO nanoparticles,and leads to the decrease in magnetic properties of PA/CFO with the comparison of pure CFO.In the adsorption experiments for Congo red(CR,anionic dyes)and methylene blue(MB,cationic dyes),PA/CFO shows a clear selective adsorption effect on MB.In the subsequent metal ion adsorption experiment,PA/CFO exhibits a strong adsorption capacity,and the Pb2+adsorption capacity reaches up to 833.8 mg g-1.The analysis of adsorption mechanism implies that the adsorption meets with the pseudo-second-oder model and Langmuir isotherms model.The reusability of PA/CFO samples is confirmed by adsorption-desorption experiments,which indicates that PA/CFO is a very promising metal ion adsorbent.2.Study on microwave absorption properties of rGO/CF nanocomposites.The graphene oxide(GO)is prepared by modified Hummers method,and then the nanocomposite(rGO/CF)of Co0.8Fe2.2O4(abbreviated as CF)and rGO are prepared by microwave hydrothermal method.The XPS measurement indicates that GO is successfully reduced to rGO.SEM images show that the CF nanoparticles attach to the lamellar rGO.The addition of rGO greatly improves the dielectric properties of CF nanoparticles,and the wave-absorption capacity of rGO/CF can be significantly enhanced due to the synergistic effect between rGO and magnetic CF nanoparticles.The best reflection loss of rGO/CF is-51.2 dB,and its maximum effective bandwidth is 7.2 GHz.The results show that the as-prepared rGO/CF nanocomposite is an excellent microwave absorbing material.