Purification Effect Of Formaldehyde And PM_2.5 For Chitosan-polypropylene Air Filter Medias

Indoor air pollution affects human health seriously,the development of air purification technology has become a hotspot of research.There is an amino group in chitosan,which can undergo addition reaction with formaldehyde.However,this property is used to modify chitosan to achieve the purpose of water treatment in most of the existing researches,but few on its application in the field of air purification.Therefore,combining theoretical analysis and experiment,this article studied about the formaldehyde purification performance and PM_2.5 filtration performance of chitosan-based blended filter media and chitosan-polypropylene composite filter media,in order to expand its application in the field of air purification.Firstly,chitosan and chitosan-polypropylene hybrid materials were prepared,and self-attenuation of formaldehyde in environment chamber was tested;secondly,the formaldehyde purification effect of polypropylene,chitosan and mixed media was tested in the environmental chamber.and the effect of chitosan content and purification time was also analyzed;lastly,to avoid the particle aggregation affecting the efficiency of formaldehyde purifying,the structure of polypropylene and chitosan double-layer filter was designed,and based on the air duct system,PM_2.5 filtration efficiency was tested under different chitosan content,the thickness of filter media and the filtration rate,at the same time,the efficiency of mixed materials and double-layer materials was compared under the same content of chitosan and resistance.The results showed that,the efficiency and rate of formaldehyde purification for both types of composite filter media increased with the increasing chitosan content,but the increasing tendency tended to be gentle.With the chitosan content of 2g and6g,purification time of 60min,the formaldehyde of environmental cabin decreased by81.1%and 97.1%.The content of chitosan had a great influence on the PM_2.5purification efficiency and resistance of the double-layer composite filter,but little effect on blending filter.With mixed material filter thickness increasing from 0.8g to2.2g,filtration efficiency increased by only 1.4%,but the resistance increased by 3Pa.Both the filter thickness and the filtration rate had a significant impact on the purification efficiency of PM_2.5 and the resistance,so these should be considered in the premise of economic reasonable selection.Under the same content of chitosan and resistance,the double-layer composite filter had higher formaldehyde purification efficiency and rate,and higher PM_2.5 filtration efficiency at the same time.