Preparation Of Cobalt,Nitrogen,Carbon Codoped TiO₂ And Study On The Degredation Of The Antibiotics In Water

Dye waste water and antibiotic waste water caused serious impact on human and ecology.Photocatalytic technology is an environmentally friendly treatment technology and has become a hot spot in the removal of dyes and antibiotics.TiO₂ is an ideal photo catalyst due to its good chemical stability,strong oxidation ability and good biocompatibility.However,the application of TiO₂is limited by its low quantum efficiency,low light utilization rate and only partial absorption of sunlight.It is significant to reduce the TiO₂ band gap and improve the photo catalytic activity of TiO₂by ion doping.In this paper,TiO₂matrix composites which can be used for the degradation of antibiotics and dyes in water were prepared by sol-gel method.The morphology,chemical composition,energy band structure,light absorption performance,separation efficiency of photo generated carrier and the photo catalytic oxidation of dyes and antibiotics were systematically analyzed by various characterization methods.The main research contents of this paper are as follows:1.Preparation and characterization of Co/N-TiO₂@C composite photo catalystThe uniform cobalt and nitrogen co-doped titanium dioxide（Co/N-TiO₂）nanoparticles were successfully prepared by sol-gel method,and the cobalt,nitrogen and carbon co-doped titanium dioxide（Co/N-TiO₂@C）nanocomposite was further synthesized by calcination.Through the analysis of the light absorption property and energy band structure of Co/N-TiO₂@C,it is found that the enhancement of its photo catalytic activity is due to the co-doping of metal（Co）and non-metal（C,N）.It was found that·O₂ and·OH played a leading role in the photo catalytic oxidation of antibiotics and dyes by detection of active free radicals.Based on the above analysis,the mechanism of Co/N-TiO₂@C photo catalytic oxidation of antibiotics and dyes was proposed.2.Degradation of dyes and antibiotics by Co/N-TiO₂@C composite photocatalystCo/N-TiO₂@C composite material was used for photocatalytic removal of pollutants from water under visible light.When tetracycline and oxytetracycline were selected as antibiotic models,the degradation rate of tetracycline reached 97.19%in60min under visible light irradiation.After three cycles,its efficiency dropped to70.19%,indicating that the catalyst had poor cycling stability,which may be caused by ion leaching and catalyst loss.At the same time,the degradation of oxytetracycline was complete（99.88%）after 60min of visible light irradiation.Rhodamine B and malachite green were selected as organic dye models.Under the optimal conditions,under visible light irradiation,the degradation rate of rhodamine B was 98.79%within10min,and after 60min,the degradation rate of rhodamine B was almost complete（99.99%）.The degradation rate of malachite green was 97.31%after 5min of visible light irradiation,and the degradation rate was 100%after 10min.