The Study On Magnetic Magnetite Nanoparticles Prepared By Solvothermal Method

Magnetic magnetite nanoparticles always display some individual applications because of their unique physical and chemical properties,and have extensive applications in such aspects as magnetic recording,ferrofluids,catalysis,medicine and pigment etc.For this reason,this dissertation presents a deeply study on the solvothermal synthesis of magnetic magnetite nanoparticles which have many excellent properties, such as monodisperse,well crystallization,higher saturation magnetization and lower coercivity.Monodisperse magnetite nanoparticles have been synthesized by solvothermal method, using FeCl₃·6H₂O and EG as reactants.X-ray diffraction,field emission scanning electron microscopy and vibrating sample magnetometer have been employed to characterize the magnetite nanoparticles.The results reveal that the magnetite nanoparticles are in inverse spinel structure.The particles don't make any agglomeration,and show us an excellent monodisperse property.The maximum saturation magnetization can reach to 79.3emu/g,and the particles show us an excellent magnetic response.Orthogonal experiment is designed to comprehensive analyze the main parameter in our system,using a L₉(3³)experiment.The results reveal that the reaction's temperature,reaction's hours and the filled value of the autoclave have a significant impact on the particles' size,morphology and crystallation.The sequence of the impact degree on particle's size is:reaction's temperature>reaction's time>filled value.The temperature make the biggest impact on the size,the particle will grow bigger as the increasing of reaction's time.The sequence of the impact degree on particles' crystallization is:reaction's temperature>reaction's time>filled value.To extent reaction time and to increase the reaction temperature are two useful methods to erthance the crystallization.How to prevent the nanoparticles' agglomeration is a difficult task in the filed of nanomaterial science.NaAc is used as an assistant reactant and anion surfactant.We research the mechanics that NaAc is added for electrostatic stabilization to prevent particle agglomeration.A study is also made that polyethylene glycol is an excellent surfactant,it can decrease the particles' surface energy so that it can prevent the particle's agglomeration efficiently.TEM and FT-IR are employed to characterize the structure,the particle is in a "Core- Shell" structure,and there's a absorbent peak at 1089.78cm^-1,it reveals the exist of RCH₂-O-CH₂R。A research in initial stage is carried for the application of magnetite nanoparticle based on the well synthesis by a solvothermal method.The produce is employed to adsorbent the heavy metal ion in waste water.ICP-AES and S2AA have been employed to characterize the concentration determination of the heavy metal ion.The results reveal that the adsorptive capacity of Cu²⁺,Cr⁶⁺and Pb²⁺for one gram adsorption agent is 4.0mmol/g,58.0mmol/g,8.2mmol/g respectively,the magnetite nanopartical's adsorptive capacity for the adsorption of the heavy metal ion in waste water is great.