Study On The Catalyst For Degradation Of Toluene Kind Volatile Organic Compounds

With the rapid development of economy,environmental issue has gradually become prominent in our country.Volatile organic compounds have become one of the major air pollutants due to their variety,serious harm,and difficulty in control.At present,the removal methods of volatile organic compounds mainly include absorption,adsorption,condensation,membrane separation,direct combustion,catalytic combustion and the other methods.Among them,the catalytic combustion has become a commonly used method in industry due to its high removal efficiency,less secondary pollution,and strong operability.The catalyst is the core of the catalytic combustion method.Hence,designing and developing a catalyst with excellent activity,stability and universality is the key point and difficulty in the development of the catalytic combustion method.Based on this,supported catalysts for VOCs combustion were designed and prepared in this paper.Firstly,the supported precious metal rhodium-based bimetallic catalysts are prepared by co-impregnation method and evaluated in VOCs combustion.In which,Rh₁Cu₃/ZSM-5 performed the best catalytic activity.The T₉₀was only 262℃over Rh₁Cu₃/ZSM-5 for toluene combustion.Rh₁Cu₃/ZSM-5 also exhibited with good stability,universality,long-run stability.The characterization results proved that Rh-Cu interaction increased the active adsorbed oxygen content on the catalyst surface,further improving the catalytic activity of the catalyst.The catalytic combustion reaction of toluene over these Rh-based catalysts mainly followed as L-H mechanism.Then,supported cobalt oxide catalysts were prepared by the co-precipitation method for the combustion of chlorobenzene or the other CVOCs.In which,Co₃O₄/ZSM-5-25 performed the best catalytic activity,and the T₉₀ was 281℃for chlorobenzene combustion.Co₃O₄/ZSM-5-25 also presented good universality for CVOCs combustion.According to characterization results,the weak acidic sites and catalyst reducibility were the main factors affecting the catalytic activity.