Research On The Preparation And Application In Simulated Wastewater Of Iron Oxides Micro-/nanomaterials

With the development of industry,the global natural environmental problems have become more and more serious.Fe-based Metal oxides were ideal catalysts which have been researched and extensively used in mechanical,chemical,medical and military because of its high thermostable,oxidation resistance,wear-resisting,anti-corrosive and other perfect physical and chemical performance.In this paper,various micro/nano-structured Fe-based Metal oxides(Fe3O4,?-Fe2O3)materials were prepared through a simple hydrothermal method and their catalytic performance on the degradation and transformation of organic wastewater were studied.The main results are summarized as follows:1.Cubic and octahedral Fe3O4 crystals were successfully synthesized with triethanolamine(TEA)as the metal chelating agent and N2H4·H2O as reducing agent.The experimental results show that the shape control of the Fe3O4 crystals was achieved by simply adjusting the amount of the NaOH.Our research also indicates that the presence of TEA is conducive to the formation of the cubic Fe3O4 enclosed by(100)planes.Under the same reaction conditions,the amount of NaOH is vital for the morphology of Fe3O4 single crystal transition from cubic to octahedral.NaOH can effectively control the relative growth rate of(100)?(111)planes of Fe3O4 crystal.At the same time,it has been demonstrated the as-prepared cubic Fe3O4 particles enclosed by(100)planes exhibit more higher catalytic activity in the reduction of p-nitrophenol to p-aminophenol than that of octahedron Fe3O4 enclosed by(111)planes and the bulk Fe3O4 particles under the same conditions.2.Dodecahedron ?-Fe2O3 enclosed by(113)planes and tetrakaidecahedron ?-Fe2O3 consists of(001)and(113)crystal planes were successfully synthesized with K4Fe(CN)6 as iron source and NaClO as oxidant.The shape control of the ?-Fe2O3 crystals were achieved by simply adjusting the synthesis parameters such as iron source,the amount of the NaOH,reaction time and reaction temperature.Our research showed that the amount of the NaOH is vital for the morphology transition from dodecahedron to tetrakaidecahedron.The photocatalytic performance of the ?-Fe2O3 polyhedron was investigated by the decomposition of Rhodamine B(RhB)under visible light irradiation.Compared with the bulk ?-Fe2O3 particles,tetrakaidecahedral ?-Fe2O3 micro-crystals exhibit outstanding photocatalytic activity of degradation RhB.The surface area of dodecahedrons and tetrakaidecahedrons ?-Fe2O3 is not very high,so we think that the enhanced photocatalytic activity on tetrakaidecahedral ?-Fe2O3 crystals may be related to their surface structure.