Study On The Treatment Of Refractory Organic Wastewater By Graphene Materials

With the rapid development of society and industry,domestic sewage and industrial waste water are increasing,and their composition and structure are becoming increasingly complex.Graphene photocatalytic degradation of refractory organics has the advantages of low energy consumption,easy operation,environmental friendliness and no hazardous waste.However,at present,there are a lot of researches on improving the photocatalytic efficiency of photocatalytic materials by combining graphene with other photocatalytic materials,and the studies on the photocatalytic performance of graphene itself are few.In this paper,GO was prepared by a modified Hummers method,and its microscopic morphology,composition and structure were characterized by scanning electron microscopy,electron energy spectrum,transmission electron microscopy,UV-vis spectrum and Raman spectrum.The results shows that monolayer or few layers graphene oxide with high oxide degree was prepared,and has visible photocatalytic ability.The refractory organic wastewater was represented by methyl orange?MO?.The performance and influencing factors of H₂O₂ cooperated with graphene oxide under visible light irradiation were studied preliminarily.Effects of catalyst concentration,pH value,stirring,aeration and light intensity on catalytic effect were discussed,and its kinetics was preliminarily explored.Finally,the effect of H₂O₂ cooperated with graphene oxide on actual wastewater was studied,and an experimental device for rapid,efficient and batch treatment of wastewater was designed,and the experiment of 10L simulated wastewater was completed.The results show that?1?The degradation rate of H₂O₂ cooperated with GO photocatalytic was much higher than the sum of that of GO and H₂O₂ under visible light irradiation.MO degrades fastest with a 7h degradation rate of 90.44%when adding H₂O₂ 4 mL and GO 0.8mL?4mg/mL?.The average photocatalytic efficiency of H₂O₂ cooperated with GO is 1.8819 h^-1,which is much higher than that of pure GO and other materials.The kinetic model of its photocatalysis can be expressed asdC/dt?28?-kC^3/2.?2?Visible light plays a very important role in the degradation of MO by H₂O₂cooperated with GO,which proves that the degradation of MO by H₂O₂ cooperated with GO can indeed generate photocatalytic reaction under visible light irradiation,rather than the simple adsorption.The degradation rate increases with the increase of light intensity.The reaction is consistent with the apparent 3/2 reaction kinetic model,and the relation between the degradation rate coefficient k of methyl orange and the intensity of light E isk?28?7.5986?10^-44 e^6.5237?10-5E?10?0.0298.?3?GO is well dispersed in the solution,with no significant change in the degradation rate whether stirring,and can be approximately regarded as homogeneous catalysis with high catalytic efficiency.When the pH value of solution is 2⁴,photocatalytic degradation is better.What is more,aeration can also accelerate the occurrence of photocatalytic reaction,and the degradation rate increases by 22.93%after 12h.?4?The effective methods of adjusting the appropriate pH value,aeration and increasing light intensity were integrated,and the method of forming water film on the slope surface significantly improved the efficiency of MO solution of GO under visible light.The degradation rate reaches 93.08%after 6h,63.8%bigger than that of H₂O₂ cooperated with GO.By adopting the idea of forming water film on the slope surface,the amplification experimental device suitable for H₂O₂ cooperated with GO photocatalysis was designed,and the solution of 10L 20mg/L methyl orange was successfully degraded.?5?The experiment of tanning wastewater treatment shows that H₂O₂ cooperated with GO can effectively reduce the content of COD,total phosphorus,ammonia nitrogen,turbidity and heavy metal in wastewater,which can purify wastewater effectively.