| As living standard is gradually improving, the indoor environmental quality that people ask also is gradually improving. a large number of decorative material and new type interior wall coating applied in people’s living space. But decorative material and new type interior wall coating have a large quality difference in different brand. Some materials even exist organic pollutants. the existence of these pollutants is becoming the hidden trouble of indoor air quality reducing in the indoor environment. formaldehyde is one of the most common pollutants. The concentration of formaldehyde often very low that is hard to deal with, dealing with low concentration of indoor formaldehyde gas has become the important research content. nanometer TiO2is a kind of excellent photocatalyst. in the200-400nm uv rays most indoor organic pollutants can be degraded, and ACF (activated carbon fiber) has a strong adsorption. the TiO2/ACF composite photocatalyst has both advantage, and can effectively deal with low concentration of indoor formaldehyde pollutant.This paper used nanometer TiO2(Deggusa P-25nanoscale), Crystal form ratio is4:1(anatase:rutile), configurating TiO2suspension liquid with a certain concentration of nanometer TiO2, and impregnating ACF in TiO2suspension liquid,useing the powder sintering process to realize nanometer TiO2curing, compound photocatalyst is preparated. Study the influence of the ACF dipping time, sintering temperature on the the preparation of compound photocatalyst TiO2/ACF. Compared with formaldehyde removal rate of nanometer TiO2ACF, TiO2/glass and TiO2/zeolite, and the results show that:photocatalyst to formaldehyde degradation rate of TiO2/ACF composite photocatalyst is better than TiO2/glass, TiO2/zeolite; when the time of ACF impregnating in nanometer TiO2suspension liquid is5minutes, it achieve adsorption saturation, load rate of nanometer TiO2is8.3%; Sintering temperature will promote nanometer TiO2curing, when the Sintering temperature is250℃, electron microscope scanning results of TiO2/ACF compound photocatalyst shows distribution of nanometer TiO2is uniformity, less agglomeration.This paper studied the influence in different load rate of the nanometer TiO2composite photocatalyst to formaldehyde degradation. When the nanometer TiO2load rate was18.7%, effect of TiO2/ACF to the degradation of formaldehyde is the best, degradation rate of formaldehyde gas which initial concentration was1.28mg/m3was92.8%. In TiO2/ACF repeat applicability, research shows, that TiO2/ACF which repeated used5times still have higher processing rate, the degradation rate80.2.%to formaldehyde when the fifth time used. The degradation rate was72.1%to formaldehyde when the sixth time used. By static trial, this paper investigated the relationship between light source intensity, gas flow rate, relative humidity, temperature, the initial concentration of formaldehyde and the formaldehyde removal rate. The results showed, the stronger the strength of the light source was, the faster photocatalysis rate was. Increase the air velocity can shorten time that the activated carbon fiber on formaldehyde adsorption saturation, and improve the degradation rate of formaldehyde; as temperature is increasing, the degradation rate of formaldehyde is increasing; when the relative humidity was 50%the degradation rate of formaldehyde reached maximum, then with the increase of the relative humidity, the formaldehyde degradation rate gradually reduced. The formaldehyde degradation rate of TiCVACF decreases gradually when formaldehyde concentration increased. When the concentration of formaldehyde was0.51mg/m3，Formaldehyde removal rate was97.6%,that showed TiO2/ACF can be effective in degradation of indoor low concentration of formaldehyde.This paper studied catalyzed photoreaction and kinetic analysis and. Conclusion is formaldehyde adsorption of TiO2/VACF can be described by Langmuir equation; Photocatalytic oxidation process can be described by Langmuir-Hinshelwood dynamics model. |
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