Setup And Properties Of Photocatalytical Reactor Based On TiO₂ Loaded Mesoporous Silica

Titanium dioxide（TiO₂）has excellent ultraviolet absorption,photocatalytic sterilization,decomposition of organic pollutants and other properties,which can be used for nano coatings,air purifiers,self-cleaning glass,ceramics and so on.Nano titanium dioxide has a wide range of application prospects in fields such as antibacterial and anti-mildew,exhaust purification,deodorization,water treatment,antifouling,weathering and anti-aging,automotive topcoats and other fields.Therefore,it has become a hot topic to construct a highly efficient TiO₂photocatalytic reaction system.This research focuses on the design and manufacture of photocatalytic reactors that are highly efficient,portable,and can be reused for gas contaminants.Main works and results of the paper are as follows:Explore the preparation process of new composite materials with high adsorption and photocatalytic activity.The use of a P25-assisted sol-gel process led to a 3.1-3.5%loading of photocatalytically active TiO₂ in the composite material,which was then used in liquid experiments.In order to enhance the bonding strength between mesoporous silica and nano-TiO₂,a new process is adopted:a commercially available liquid high-dispersion photocatalyst is used as a nano-TiO₂source,and reagent-grade chromatographic silica（mesoporous silica）is used as an adsorbent,CMC as adhesives for the current two materials.After a certain process the composite material is obtained.By measuring the specific surface area and porosity of the material,it was found that the loss of performance of the adsorbent does not exceed 8%.In order to establish an efficient photocatalytic reactor,a semi-leak plastic optical fiber was specifically designed and prepared.The light leakage characteristics of the optical fiber are characterized:a diameter of 0.5 mm and a length of 30 cm can achieve a leakage of more than 70%of the light energy incident into the optical fiber.Semi-leak fiber added with ultraviolet LED as light source,concentration detection device,reaction vessel and other accessories are assembled into a complete photocatalytic reactor.In the later experiment of high-concentration and high-air-flow pollutant degradation,the light source system of the reactor was replaced with a higher-power UV LED array.Photocatalytic degradation of methyl orange solution verification test.The results show that the degradation process is the process of adsorption and photocatalytic linkage;using the control group and control variables to test the effectiveness of the dispersion fiber design,the increase in optical power can accelerate the degradation reaction;there is saturated light power,that is,increase the optical power,The speed of the reaction will not have a significant gain,and the general method of determining the saturated optical power of a particular device is discussed.Photocatalytic degradation of formaldehyde gas verification test.In the low-concentration（0.7 mg/m³）of small gas flow（2L/min）degradation test,it is absorbed at least 3mg of formaldehyde gas during the adsorption saturation phase of the previous 20h;when the filter of adsorption saturation,LED light power of540mW,real-time photocatalytic decomposition rate of formaldehyde achieved72μg/h,the output formaldehyde concentration dropped to 0.09mg/m³,which is lower than the safety threshold of indoor formaldehyde concentration in the national health standards.In the high-air-flow experiment（18L/min）,the real-time decomposition efficiency of 0.5mg/m³ was also obtained during the degradation process.In a high concentration（around 10 mg/m³）high-air-flow experiment,the cumulative removal rate was defined to characterize the cumulative removal effect of adsorption and photocatalysis from the beginning of the experiment to a certain time.By analyzing the cumulative removal rate during the experiment,the photocatalytic film prepared by different photocatalysts was compared with its degradation ability,and the improvement of formaldehyde gas degradation efficiency was determined by the high concentration photocatalyst active ingredient,and the performance of the photocatalyst sheet was repeated when used repeatedly.Falling situation.This study has achieved phased results.To achieve practical use,we should adjust reactor size,structure,and material usage to achieve a suitable systemic respiratory resistance.Therefore it is expected to play a practical role in the development fields of portable air purifiers,long-lasting gas masks,and chemical weapons protection.