Design And Performance Study Of Air Duct Type Photocatalytic Air Purifier

In recent years,the problem of indoor air pollution in our country has become more and more serious.Volatile organic compounds（VOCs）have become more frequently polluted.It has a wide range of sources and it is also difficult to control.Some VOCs have seriously toxicological effects,which are hugely harmful to human health and the natural environment.The current treatment technology for industrial waste gas is not suitable for indoor VOCs purification,so it is urgent to further research the purification technology for indoor VOCs.Photocatalytic technology has been widely used in the degradation of environmental pollutants since the 1970s.It has huge market applications in the treatment of formaldehyde and VOCs in indoor air purification,and it also occupy a huge market share.However,the current general photocatalytic indoor purification technology is based on the sol-gel state catalyst sprayed on the surface for the purification of the initial indoor decoration,and there are relatively few indoor air purifiers with photocatalysis as the core technology.Based on this,we designed and built an air duct photocatalytic purifier by ourselves,which can be used for the purification of indoor VOCs.In this study,Si C-based composite materials were first prepared by hydrothermal method and characterized by a series of characterization methods.Such as field emission scanning electron microscopy（SEM）,X-ray electron spectroscopy（XPS）,X-ray diffraction（XRD）and other characterization methods to determine WO₃,Ti O₂ was successfully loaded onto the Si C surface.Ultraviolet-visible diffuse reflectance spectroscopy（UV-vis DRS）and photoluminescence spectroscopy（PL）results show that the loaded material Si C/WO₃-Ti O₂has a stronger absorption capacity in the ultraviolet region than Si C,and it is effectively suppressed the recombination of photogenerated electrons and holes,extending the life of photogenerated electron-hole pairs to a certain extent.The results of AC impedance（EIS）and photocurrent response test（PC）show that not only the conductivity is enhanced after modification,but the photo-generated carrier migration efficiency is also improved to a certain extent.Degradation experiments show that the material has good degradation ability for VOCs.The removal rate of toluene with an initial concentration of 100 mg/m³ is close to 80%within 1 min,and the performance does not decrease significantly after five cycles.It has good stability and can be better qualified for the oxidation module of photocatalytic air purifier.Based on the above results,the conceptual diagram of the photocatalytic air purifier was designed,using Workbench to simulate and analyze the fluid flow in the purifier,and optimizing the components of the purifier based on the results,and using the Si C-based composite material of the oxidation module to build a photocatalytic air purifier with low cost and good purification ability,and using ethanol as the target pollutant,the optimization experiment was carried out using different lamp sources with a dominant wavelength of 365nm.A series of purification experiments were carried out with 365nm UV lamp beads.The results showed that when 10 catalysts were used,the humidity was 60%,and the initial concentration of the ethanol inlet was 50 mg/m³,the photocatalytic air purifier had the best purification ability,the degradation rate can reach 85%.