Study On The Preparation,characterization And Photocatalytic Performance By Co/C Co-doped TiO₂ Nanoparticle Catalyst

This paper intended to modify nano TiO₂ particles with Co and C,then evaluated the structure and their photocatalytic performance for chlorophenol degradation in the ultraviolet light.The modification by doping and co-doping of TiO₂ were prepared through sol-gel methods,that tetrabutyl orthotitanate as raw material,glacial acetic acid as inhibitor,Co?NO3?2?6H2O and glucose.The crystal morphology,composition,type and structure,as well as the optical property of the materials were characterized by X-ray diffraction?XRD?,the scanning electron microscope?SEM?and UV-vis.According to the results of degradation to phenol,the best calcination temperature was 450 oC and the optimum proportion of co-doping photocatalyst was 0.035%Co2+ and 2.55%C.With the best co-doping Co-C/TiO₂ as photocatalyst,the effects of degradation time,the amount of catalyst,the initial concentration,volume of H2O₂ and the value of pH on photo-catalytic degradation to phenol,2,4-dichlorophenol and pentachlorophenol sodium were investigated.The results of single factor experiment showed that the amount of photocatalyst and the initial concentration greatly affected the three kinds of phenolic compounds.But pH value had different influence on the degradation of different objects: acidic conditions conducive to the degradation of phenol and 2,4-dichlorophenol,and weak alkaline environment beneficial to the degradation of pentachlorophenol sodium.Orthogonal experiments concluded that the optimal degradation amount of 2,4-dichlorophenol and pentachlorophenol sodium was about 198.10mg/g and 453.82mg/g.The experiment optimization and degradation model of phenol were established by using response surface methodology,which indicated that the amount of catalyst was 0.05 g,the initial concentration of phenol was 17.44?g/mL,pH=5.68,with the degradation time of 120 min,the optimal degradation amount of phenol was about 15.67mg/g.The degradation kinetics and mechanism of the modified TiO₂ photocatalyst were discussed about phenol,2,4-dichlorophenol and sodium pentachlorophenol.It was found that three kinds of chlorophenol degradation processes were in line with the first order kinetics.As for the degradation of phenol sodium chloride,which used L-H model fitting and fitted well.According to the ultraviolet absorption spectra and references of degradation process that predicted the three kinds of chlorophenol degradation mechanism and degradation pathway mainly including three steps: dechlorination,hydroxylation,and open loop,eventually turned into CO₂,H2 O and other small molecules.