Construction And Photocatalytic Performance Of Goethite Based Photocatalyst With Visible-light Response

With the acceleration of industrialization,environmental problems which particularly water pollution have become more and more serious.Photocatalysis is the most efficient and sustainable development mode for energy conversion and pollution control.Photocatalysis is a process of photoinduced semiconductor,which promoting carrier separation or generating free radicals,and eventually degrading organic dyes and other toxic or harmful pollutants into H₂O and CO₂.It has the advantages of mild reaction conditions,deep purification and direct use of sunlight.Therefore,it is also regarded as one of the most promising environmental protection technologies in the 21st century.Due to goethite has a stable nature,large specific surface area,suitable forbidden band width,and huge reserves in nature.It has great potential in the field of environmental pollution control.In this study,?-FeOOH and its composite photocatalytic materials as the research object were prepared by mechanical force solid phase method.And the optimization and regulation of goethite based photocatalytic materials were realized.In combination with the composition,structure,microstructure and characterization of photocatalytic properties about the synthesized?-FeOOH based photocatalytic material.It is that the mechanism of?-FeOOH's combination with LAS and TiO₂ as well as the regulation of its photocatalytic properties by magnetic field are explained and analyzed.1)Preparation of?-FeOOH by mechanical solid phase method and its photocatalytic properties.Granular or rod-like nano?-FeOOH can be prepared by mechanical force solid phase method.Fe?NO₃?₃·9H₂O is taken as the iron source,?NH₄?₂CO₃ was used as the hydroxyl source.The molar ratio of the two was 1:4.5,the ball-feed ratio was 2:1,the ball grinding speed was 38 rmp·min^-1,the ball grinding time was 3 h,and the aging time was 48 h at 60?.In addition,the effects of FeCl₃·6H₂O and Fe?NO₃?₃·9H₂O iron sources on the morphology,microstructure and photocatalytic performance of?-FeOOH were investigated.The results show that hetero-charged anions have great influence on Fe³⁺nucleation.It was shown that the visible light catalytic performance of the?-FeOOH?FC?prepared from FeCl₃·6H₂O was better than that of the?-FeOOH?FN?prepared from Fe?NO₃?₃·9H₂O.The photocatalytic degradation rate was 22.3%and 15.0%for 300 min,and its fluorescence and photoelectric chemical properties were similar to that of the visible light.2)Preparation of?-FeOOH/LAS composite visible photocatalyst.The rod-like?-FeOOH/LAS nanometer was obtained by mechanical force solid phase method.With the increase of LAS content,the adsorption capacity and the photocatalytic capacity of?-FeOOH/LAS gradually increased by the photocatalytic oxidation of rhodanine RhB.When LAS content was 4.0%,the total removal rate of organic dyes reached more than 96.0%,and the photocatalytic performance accounted for 46.5%.The results show that the porous LAS can resist the high agglomeration of?-FeOOH,and then its improve the ability of non-light adsorption and expose more active sites.On the other hand,LAS has a small amount of SP2hybridized C,which has a certain conductivity and help the carrier separation of?-FeOOH.3)?-FeOOH/TiO₂ heterostructure construction and visible photocatalytic performance study.Mechanical force solid phase method was used to obtain the composite structure of?-FeOOH/TiO₂.It can be seen that the photocatalytic oxidation of rhodanine RhB showed that the 5 h degradation rate about F70@T30 was 1.5 times and 26 times higher than that of?-FeOOH and TiO₂ respectively.The photocatalytic reaction rate per unit specific surface area was 4.1 and 5.0 times higher than that of?-FeOOH and TiO₂.The results show that the effect of heterojunction can improve the separation efficiency of photoborne carriers and the photocatalytic performance of visible light.4)Preparation of?-Fe₂O₃/LAS visible light photocatalyst under magnetic field induction.The nanometer?-Fe₂O₃/LAS structure was obtained by mechanical force solid phase method and thermal decomposition method.It was used in visible photocatalytic oxidation of methylene blue MB.The results showed that the degradation rate of?-Fe₂O₃/LAS in the visible photocatalytic degradation 5 h was 18%,the visible photocatalytic degradation under the magnetic field 5 h was 25%.The results show that?-Fe₂O₃/LAS of built-in electric field was enhance to improve its photocatalytic performance by magnetic field...