Research On The Adsorption-Thermocatalytic Oxidation Coupled Component For Indoor Air VOCs Purification And Its Application In Air Purifier

Volatile organic compounds(VOCs)are the main pollutants in indoor air,which come from building materials,indoor decorating materials and office supplies.Among different VOCs-abating technologies,thermo-catalytic oxidation is an effective way to solve VOCs pollution.The catalysts used in thermo-catalytic oxidation of VOCs contain noble-metal catalysts and non-noble metal catalysts.And the T90 of noble catalysts is much lower than that of non-noble catalysts.The traditional heating and noble metal catalysts are two separate components,which are difficult to be applied in household air purifiers.Therefore thermo-catalytic oxidation is limited in the usage in household air purifiers.In this paper,a VOCs adsorption-thermo-catalytic oxidation coupling component was studied.The noble metal catalyst powder was coated directly on the PTC heating component to combine traditional heating component and the noble metal catalyst.As a result,the temperature of the thermal catalytic oxidation was reduced,and the volume of the component was greatly reduced.Finally,the thermal catalytic oxidation VOCs component were installed in the air purifier and the performance test was performed.The contents and results are as follows:1.Ptlγ-Al2O3(2wt.%)powder catalyst was prepared by impregnation method and characterized by XRD、SEM、EDS.The conversion rate of o-xylene at different temperatures was tested.The T90 of 2wt.%Pt/γ-Al2O3 is 178℃,lower than the Curie temperature of PTC(250℃).2.The coating method of Pt/y-Al2O3 powder catalyst on the surface of the honeycomb PTC heating resistor was studied.A series of procedures including treating the PTC heating resistor surface,coating the substrate,coating the catalyst was conducted to produce the PTC catalytic component.The final product was tested for the catalytic oxidation o-xylene at different temperatures.The T90 of PTC catalytic component is 205 ℃,lower than the Curie temperature of PTC(250℃).The temperature of direct thermal catalytic of o-xylene is between 200 ℃ and 300 ℃.3.Several PTC catalytic components were installed into air purifiers,and tested for the performance curve of the decontamination O-xylene in a closed laboratory chamber.The total volume of 211.2ml PTC catalytic components has a purification efficiency of about 32.9%for o-xylene in 1 hour,90.8%in 6 hours,and a purification efficiency of about 91%for formaldehyde in 4 hours.