Study On Dynamic Sterilization And Degradation Of Formaldehyde By Nano-Zinc Oxide Photocatalytic Technology

With the development of economic and social,people spend longer time staying at home.Therefore,whether the indoor air is clean,that is,whether the indoor air quality meet the requirements catches a wide range of attention from the public.Treatment of microbial and formaldehyde pollution is an important work because that they are important indoor air contamination.Photocatalytic oxidation technology is a more effective means to control bacterial and formaldehyde pollution.Nano-ZnO has good catalytic properties and selectivity,which is considered as a highly active photocatalyst with great application prospect.However most of the studies on photocatalytic sterilization and degradation of formaldehyde are conducted using static mode or continuous mode on low flow rate condition and thus this technique still in experimental stage.Therefore,the study on dynamic sterilization and degradation of formaldehyde by nano-ZnO photocatalytic technology has greater practical significance for improve indoor air quality.Through the experiment method,the effect of nano-ZnO dynamic sterilize and degrade of formaldehyde by UV lamp with power of 8W is studied.The effect of flow rate,contract area and so on is studied too.First,the spectrum of UV lamp is tested and found that the main wavelength of UV lamp is about 253nm.The structure of the nanometer zinc oxide is characterized.The particle size is about 100nm.The experiment of nano-ZnO dynamic sterilization against Staphylococcus albus shows that,nano-ZnO photocatalytic technology has fine effect of sterilization.The dynamic sterilization efficiency of nano-ZnO photocatalytic technology reaches71.2%when the temperature is 24±1℃,relative humidity is 50%,and the contract area per unit air volume is 6m~2/(m~3/s).The results show that the dynamic sterilization efficiency decreases with the increase of flow rate,increase with the increase of contract area,decreases with the increase of relative humidity.Moreover,nano-ZnO photocatalytic technology does not selective kill a certain size of bacterial particles.The experiment of nano-ZnO dynamic degradation of formaldehyde shows that,once through efficiency of dynamic degradation of formaldehyde decreases with the increase of flow rate,increase with the increase of contract area,decreases with the increase of initial formaldehyde concentration.But under the certain experiment condition,once through efficiency of nano-ZnO photocatalytic technology dynamic degradation of formaldehyde is lower than 20%,so it is important to find effective means to improve the degradation efficiency.