| Methylamine(CH3NH2,MA)is a typical amine malodorous gas,which is often produced in the p ro cess of sewage treatment,and is widely used in industry as a common raw material and intermediate.The methylamine olfactory threshold is 0.021 mg/nm3.In addition,methylamine is stable and difficult to biodegrade,and can adversely affect many tissues and organs of the human body.At the same time,Chinese residents are densely populated.Industrial areas and municipal facilities are close to residential areas in some areas.Therefore,methylamine is one of the atmospheric pollutants,which seriously affect the environment and human health,are urgently needed to treat.But,at present,there iswas little research on its treatment methods.Activated carbon(AC)is an excellent adsorbent.Generally,commercial activated carbon has good adsorption to non-polar compounds,has poor adsorption performance for polar substances such as methylamine,which has low adsorption capacity and short penetration time..In this paper,several modified methods of activated carbon were carried out,and a variety of modified activated carbons were prepared.The adsorption of methylamine by modified activated carbon was studied by dynamic adsorption experiments of methylamine.Firstly,a modified activated carbon with large adsorption capacity was prepared by oxidation of nitric acid.Under the optimal modification conditions,it was stirred at 70 ? for 6 h in 70%nitric acid,and its breakthrough capacity could reach 517.30 mg/g.It is 45.70 times higher than the original activated carbon.By BET and FTIR characterization,it can be found that the nitric acid modification increases the number of oxygen-containing functional groups on the surface of the activated carbon and changes the surface structure of the activated carbon.The results of adsorption kinetic model fitting show that the adsorption of methylamine by modified activated carbon is a combination of physical and chemical adsorption.When close to equilibrium,the absorption rate of MA is controlled by intraparticle diffusion.After that,the metal oxide modified activated carbon was prepared on the basis of oxidative modification.A variety of metal ions were selected for comparative analysis,and Fe oxide modified activated carbon was selected as the main research object.The effects of loading and calcination temperature on the adsorption capacity were investigated.The modified activated carbon was characterized by BET,FTIR,EDX and XRD.Under the optimal conditions,the adsorption capacity of iron oxide modified activated carbon was 206.49 mg/g,which was 18.24 times higher than that of the or:iginal activated carbon.At the same time,it was found that modified activated carbon can achieve 64%?82%by hydrogen peroxide.The recycling can completely oxidize and degrade methylamine without causing secondary pollution to the environment.At the same time,the adsorption kinetics of modified activated carbon is studied.The effects of experimental conditions such as methylamine concentration,gas flow rate,gas flow humidity,bed height and bed temperature during adsorption on the adsorption capacity of modified activated carbon for methylamine were investigated.Finally,the noble metal Pt was used to modify the activated carbon.The degradation efficiency of methylamine by platinum-based catalyst with activated carbon was studied.The experimental results show that the hydrothermal method can well support Pt on the activated carbon support.The catalyst prepared at 350 ? can completely degrade methylamine.With the increase of Pt content,the catalytic degradation ability of Pt/C catalyst to methylamine increases. |
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