Study On Manganese-based Catalyst Supported On The Surface Of Nonwoven Fabric And Its Catalytic Degradation Of Ozone

Ozone is a strong oxidizing secondary air pollutant,long-term exposure to even low concentration ozone can cause great adverse effects on people's health including increasing respiratory system and cardiovascular disease.Catalytic decomposition is the most effective method to remove ozone.Among the developed catalysts,manganese dioxide(MnOx)as a well-known transition-metal oxide has attached much attention due to its outstanding activity.However,the widespread application of the individual protection and indoor air purification of MnOx catalyst in the form of particles and powders were limted due to the difficulty of moding and dust pollution in high flow velocity conditition.In this paper,the carboxylated polypropylene(PP)nonwoven was prepared by grafting of acrylic acid(AA)onto the surface of PP nonwoven using ultraviolet irradiation,and subsequent self-assembly MnOx particles onto the surface of PP-g-AA nonwoven.The effects of grafting conditions to the grafting degree of PP-g-AA were studied,in addition,the grafting degree,particles concentration and milling time to the loading rate of MnOx/PP-g-AA nonwoven were investigated.The as-synthesized materimals were comprehensively characterized by SEM,EDS,BET,ATR-FTIR and XPS technologies.The experimental results showed that grafting degree of AA 60%,concentration of MnOx 5g/L and milling of time 2.5h were the optimal conditions for self-assembled,the loading rate of MnOx could reach 58.63%.The catalytic performance of MnOx/PP-g-AA nonwoven for ozone were investigated by dynamic experimental,the effects of the loading rate,relative humidity,air velocity and ozone concentration to the catalytic activity of ozone were discussed.The deactivation mechanism of MnOx/PP-g-AA was dicussed by the Mn 2p3/2 and Mn 3s XPS spectra,the pressure drop and intercept PM2.5 performance of the MnOx/PP-g-AA nonwoven were studied.The results showing that ozone conversion rate remained near to 100%at the continuous reaction 6 h under ozone concentration of about 1 ppm,laoding rate of 58.63%,air flow velocity of 1000 ml/min,and relative humidity of 45%.The highest filtration efficiency and preesure drop of the nonwoven were near 78%and 56 Pa,respectively under face velocity of 5.55 cm/s.In the end,the effects loading conditions such as concentration of MnOx and grafting degree to nonwoven were studied.The results showing that nano honeycomb MnOx particles were easily to agglomeration,which is not conducive to dispersion in water phase,however,the MnOx/PP-g-AA nonwoven loading nano honeycomb MnOx could show the better catalytic decomposition ozone performance.