Preparation Of Al Based Composite Catalyst And Study On Catalytic Degradation Of Cyanide Containing Wastewater

In recent years,the rapid development of industrial technology has brought great challenges to the treatment of all kinds of industrial wastewater.At present,a large number of industrial wastewater has caused serious pollution to the environment,especially the cyanide-containing wastewater,which is more toxic and has a far-reaching impact on the environment.The sources of cyanide-containing wastewater are relatively wide.Coking,medicine,chemical fiber,plastics,mineral processing,electroplating,gas,agriculture,metallurgy,metal processing and other industries will produce cyanide-containing wastewater.However,the current situation of the treatment of cyanogenic wastewater is still not optimistic,and the unmet emission of cyanogenic wastewater,still affects the balance of environmental ecology and human health.Therefore,it is urgent to research and develop the treatment methods of cyanogenic wastewater so that it can be up to the standard of discharge.In this paper,the heterogeneous Fenton-like catalyzed degradation of cyanogenic wastewater was carried out,where it used prepared and optimized Al-based composite catalyst,adding H₂O₂as oxidant,and meanwhile the degradation process were investigated.The supportγ-Al₂O₃was prepared by the method of homogeneous precipitation,and the active components were loaded by the method of impregnation,the COD degradation rate of acrylonitrile wastewater used as an indicator.According to screening experiments,it was known that the catalyst Cu O-Nd₂O₃-Co₃O₄/γ-Al₂O₃had the best effect on catalytic H₂O₂degradation of acrylonitrile.Cu O-Nd₂O₃-Co₃O₄with mass fraction of 2%-2%-2%had the best performance.The catalyst Cu O-Nd₂O₃-Co₃O₄/γ-Al₂O₃was subjected to performance tests of reusability,and it proved that the catalyst could still achieve nearly 90.0%COD degradation rate in wastewater after it had been used six times,which indicated the catalyst Cu O-Nd₂O₃-Co₃O₄/γ-Al₂O₃exhibited good reusability and stability.The support as well as the Al based composite catalysts were structurally analyzed by the characterization method of XRD,FT-IR,SEM,EDS and XPS.The results showed that the catalyst support wasγ-Al₂O₃with irregular shape,which was mesoporous material.The doped active components have all been loaded onto the surface of the support and have not changed the structure of the support.The valence states of the catalyst before and after the reaction did not change,which only played the role of changing the rate of reaction during the process.The acrylonitrile wastewater and acrylic wastewater were degraded by using the method of heterogeneous Fenton-like,and the effects of original COD concentration,catalyst usage,solution p H,H₂O₂usage,and reaction temperature on the catalytic degradation process were investigated.It turned out that the Al based composite catalysts prepared in this experiment could degrade acrylonitrile wastewater with high efficiency.Among this,the optimal COD concentration of acrylonitrile wastewater was 2500 mg/L,the optimal catalyst usage was 10 g,the optimal reaction solution contained initial p H was 8,the optimal H₂O₂usage was 30 m L,and the optimal reaction temperature was 70℃,and under the optimal conditions,the optimal degradation rate of acrylonitrile with COD 2500 mg/L could be achieved up to 94.7%after 90 minutes;the Al based composite catalyst prepared in this experiment could degrade acrylic wastewater efficiently.Among this,the optimal concentration of COD of acrylic wastewater was 700 mg/L,the optimal catalyst usage was 5 g,the optimal reaction solution initial p H was 7,the optimal H₂O₂usage was 20 m L,the optimal reaction temperature was 80℃,and under the optimal conditions,the optimal degradation rate of acrylic acid with COD 700 mg/L could reach 89.1%after 60 minutes.