Study On The Treatment Of Indoor Formaldehyde By Photocatalytic Technology Of Titanium Dioxide

In modern society,people’s quality of life is greatly improved,and the quality of indoor air is also more stringent.The rise of interior decoration has also caused a series of air pollution problems.Therefore,indoor air quality is attracting more and more attention.The air pollution is increasingly rampant today.Nano TiO₂ photocatalytic technology can degrade some organic and inorganic small molecules,and put them into a completely harmless inorganic small molecules.Because of its strong stability and reusable advantages,it has many advantages in environmental protection than the traditional methods,such as energy saving.However,pure titanium dioxide has low utilization efficiency and poor photocatalytic effect,which limits its application.Therefore,titanium dioxide should be modified to enhance its photocatalytic efficiency under visible light.In this study,the modified nano titanium dioxide powder and silver titanium dioxide powder were characterized by XRD,SEM and TEM.In the self-made environmental test cabin,we use the plate which release formaldehyde to simulate the newly decorated indoor environment.We carried out experiments on modified nano titanium dioxide powder and silver titanium dioxide powder to explore the effects of concentration,temperature,humidity,light source and titanium dioxide on formaldehyde degradation.In addition,we put applied the experiment into practice and made a cleaning board which has dual functions of beauty and air purification.On this basis,we also explored the influence of binder on formaldehyde degradation,and got the formula of catalyst consumption and the area catalytic plate.The results are as follows:（1）The modified nano titanium dioxide powder is made by ourselves.The results of XRD characterization showed that the modified nano titanium dioxide powder is a kind of mixed crystal type of rutile and anatase.The average particle size of powder powder is about 18.1nm.;TEM results showed that the self-made nano silvertitanium dioxide powder had good dispersion,but the phenomenon of agglomeration isn’t appeared.Simulation of pollutants with formaldehyde,if we increase the initial concentration of formaldehyde,the degradation efficiency of formaldehyde will increase.At the same time,we found that thephotocatalytic degradation efficiency decreases with the decrease of formaldehyde concentration.When we studied the effect of temperature and humidity on formaldehyde degradation,it is found that the best condition of formaldehyde degradation is 25℃ and 50%humidity.When we studied the influence of the photocatalytic degradation effect on the light source,the two UV lamp of formaldehyde degradation is more than 80%.when the amount of titanium dioxide is 40g,the efficiency is more than 84%.（2）XRD date of modified nano titanium dioxide powdershowed that the homemade silver nano titanium dioxide powder is a mixture of rutile and anatase crystal type,the average particle size of the powder powder was about 18.3nm;TEM results showed that the self-made nano silvertitanium dioxide powder had good dispersion,but the phenomenon of agglomeration isn’t appeared.Simulation of pollutants with formaldehyde,if we increase the initial concentration of formaldehyde,the degradation efficiency of formaldehyde will increase.At the same time,we found that the photocatalytic degradation efficiency decreases with the decrease of formaldehyde concentration.In the study of the impact of temperature and humidity on formaldehyde degradation,the temperature of 25 degrees Celsius and humidity of 50%is the best conditions.In the study of influence of the light source of formaldehyde degradation,the degradation efficiency of using a UV lamp is similar to that of two UV lamp.They reached more than 90%.when the amount of titanium dioxide is 40g,the degradation efficiency is more than 93%.（3）In the application of titanium dioxide,the effect of water,pure acrylic emulsion and sodium alginate on the formaldehyde degradation was studied.The experiments showed that the degradation of formaldehyde was ammonium alginate>water>pure acrylic.For the bonding condition,the photocatalyst catalyst containing pure acrylic solution had the best adhesion effect and no skin peeling phenomenon.The photocatalytic catalyst plate containing sodium alginate had the second effect,and the water spray coated photocatalyst is the worst.Besides,we have developed the formula y=s×h×（C-C0）/0.06446 for the amount of titaniumdioxide needed to achieve the formaldehyde standard in any indoor space and the formulay = s×h×（C-C0）/2.57839 for the area needed of the air cleaning plate.Based on the reaction chamber designed by ourselves,the optimum reaction conditions of photocatalytic degradation of formaldehyde by modified TiO₂ and Ag-TiO₂ were found through the study of temperature,humidity,formaldehyde concentration,light source and titanium dioxide content.In addition,a better binder was selected and the formula of the amount of catalyst and the area formula of catalyst plate were calculated.