Fabrication Of TiO₂ And Mn Based Catalysts With Highly Exposed {001} Facets And Their Performance For Degradation Of The Volatile Organic Pollutants

Since the 20th century,China entered the ranks of industrial power,followed by the increasingly serious air pollution problem.In the case of nitrogen oxides and particulate matter being effectively controlled,the prevention and control of volatile organic compounds has become the focus of atmospheric environment in China.This paper first through the study of industrial VOCs emissions accounted for the largest proportion of textile printing and dyeing industry,analysis of its production and pollution nodes and total pollutants will be conducive to the development of reasonable VOCs control measures.Based on the research of textile printing and dyeing industry,toluene and styrene will be selected as the target pollutants for catalytic oxidation experiments.Catalytic oxidation technology is the most widely used VOCs treatment technology because of its low combustion temperature,low energy consumption and high efficiency.Among the transition metal catalysts developed in recent years,manganese series catalysts have attracted more and more attention because of their high efficiency.TiO₂is often used as a carrier in catalytic oxidation due to its non-toxic,strong stability,good dispersity of active components and low price.In this paper,gas chromatograph was used to analyze the pollutants collected in silane SUMMA sampling tank of a representative textile printing and dyeing enterprise in Guangdong Province.In this study,volatile organic compounds（VOCs）generated during printing and dyeing were analyzed for their source components,and the effects of inhalation risk assessment procedures recommended by the United States Environmental Protection Agency（EPA）on worker health were assessed.The results showed that among the 36 volatile organic compounds detected in the printing and dyeing process,the halogenated hydrocarbon was the most species and the content of aromatic hydrocarbon was the highest.Acetone in OVOC,chlorobenzene in aromatics,toluene in aromatics and n-hexane in alkanes are account for most of the ozonogenesis potential.Risk thresholds are exceeded for both carcinogenic and non-carcinogenic diseases.Mn-Ce/TiO₂-HF catalyst was prepared on TiO₂-HF support with high exposure ratio of{001}crystal surface obtained by hydrothermal method.Mn-Ce/TiO₂-AC catalyst was also prepared by TiO₂-AC with high exposure ratio of{101}crystal surface obtained by hydrothermal method.It was found that Mn-Ce/TiO₂-HF catalyst was superior to Mn-Ce/TiO₂-AC catalyst in the degradation efficiency of toluene and styrene.The BET,XRD,O₂-TPD,H₂-TPR and other micro characterization of Mn-Ce/TiO₂-HF catalyst combined with the activity test results further showed that Mn-Ce/TiO₂-HF catalyst with active metal loading of 18%:6%,calcination temperature of 300℃ and reaction space rate of 48000h^-1reached the optimal.The toluene conversion rate reached 98%at 235℃,and the final selectivity of CO₂reached85%.Styrene achieved a conversion rate of 98%at 260℃ and the final selectivity of CO₂reached 90%.The TiO₂-HF carrier with high exposure ratio of{001}crystal plane can increase the specific surface area of the catalyst,promote the interaction between Mn-Ce,and improve the catalytic oxidation activity of the catalyst.Meanwhile,Mn-Co/TiO₂-HF catalyst was prepared by the same method,and the degradation efficiency of toluene and styrene was discussed.In this paper,through the research and analysis of VOCs in the key industry（printing and dyeing industry）for the future emission reduction measures to lay a foundation,at the same time,developed a kind of efficient{001}crystal TiO₂as the carrier of manganese catalyst.