Preparation Of Nano?-Fe₂O₃ With Three Dimensional Flower-Like Structure By One Step Method And Its Properties

With the wide applications of nanomaterials,magnetic nanomaterials have attracted wide attention in various fields due to their functionality and particularity.Among many magnetic nanomaterials,nano-?-Fe₂O₃ has broad application prospects in environmental governance,electronic information,biomedicine and other fields because of its high stability,low cost and good biocompatibility.At present,many morphologies of?-Fe₂O₃ nanomaterials have been reported in the literature,and it has been found that their properties have special relationship with morphologies.Therefore,the preparation of nano-?-Fe₂O₃ with special structure is particularly important.Based on this,in the present study,nano-?-Fe₂O₃ with flower-like morphology was prepared by a one-step solid-phase thermal decomposition using ferric nitrate?Fe?NO₃?₃×9H₂O?as raw material and cetyltrimethylammonium bromide?CTAB?as structure-directing agent,and its formation mechanism was also discussed.Furthermore,the adsorption properties of synthesized nano-?-Fe₂O₃ for weak acid dark blue dye and Congo Red were investigated.1.Flower-like?-Fe₂O₃ was prepared by a solid-phase thermal decomposition method using ferric nitrate as iron source and CTAB as structure-directing agent.The formation conditions of flower-like?-Fe₂O₃ were explored by varying CTAB dosage,heating temperature and heating time.The obtained flower-like?-Fe₂O₃ was characterized by XRD,BET,VSM,DTA,SEM and TEM,and its formation mechanism was studied.The results show that the increase of heating temperature and CTAB content are beneficial to the formation and integrity of flower-like structure.The optimal conditions for obtaining flower-like?-Fe₂O₃ corresponded to a CTAB dosage of 15%,a heating temperature of 200?and a heating time of 2 h.The average crystallite size,saturation magnetization and specific surface area of flower-like?-Fe₂O₃ obtained at this condition was found to be 17.2 nm,37.8emu/g and 65.4 m³/g,respectively.2.Flower-like?-Fe₂O₃?sample C10-200?was used as adsorbent to study its adsorption performance for weak acid dark blue dye solution and to explore its adsorption performance under different conditions.The results showed that C10-200 adsorbed weakly acidic dark blue better under acidic conditions,and the adsorption fitted well the quasi-second-order adsorption model and Langmuir adsorption model.The theoretical adsorption capacity of C10-200to weakly acidic dark blue was 72.6 mg/g.3.Flower-like?-Fe₂O₃?sample C15-200?was used as adsorbent to study its adsorption properties for Congo red dye solution,and the adsorption properties under different conditions were investigated.The results showed that the adsorbent C15-200 exhibited a good adsorption performance for Congo Red at neutral condition?pH=6.9?.The adsorption conformed to the quasi-second-order adsorption model,Langmuir adsorption model and Freundlich adsorption model,and the adsorption capacity of C15-200 on Congo Red was 101.3 mg/g.