Research On Dynamic Disinfection Of Indoor Air Applying UV And Catalytic Ozonation

Nowadays people spend the most time in the indoor environment, and with theurban population density increasing, the microbial aerosol pollution of air is more andmore serious, which causes the respiratory infection up to20%and results in manysymptoms, such as difficulty in breath, dizziness and headache, causing harm topeople’s health; as a consequence, the problems must be solved.In this paper, homemade vacuum ultraviolet lamp was selected as the light source.Combining the ultraviolet and ozone, its sterilization effect on the target microbialaerosol was studied. According to the UV lamp’s structural features and relatedinformation research, the UV reactor’s size was determined. UV light intensitydistribution was analyzed, and its stability of power and ozone production rate weretested; the ozone catalyst, catalytic carrier, loading methods and thickness of the catalystlayer were optimized, and Escherichia coli and Bacillus subtilis spores were chosen astarget organisms. Influence factors including air flow rate, relative humidity, organicmatter content, microbial species and UV intensity ultraviolet light on sterilization rateof UV reactor at one pass were studied, at the same time, air flow rate, ozoneconcentration, relative humidity, microbial species on sterilization rate of ozonecatalytic reactor at one pass were studied. Finally, in the microbial aerosols simulatedscene, the sterilization rate of combined device under different sterilization time,relative humidity, organic matter content, microbial species were studied; in themeantime, the sterilization rate of combined device in actual sites were studied.According to the UV lamp’s structural features and related information research,UV reactor was made as a cylinder; its diameter was250mm with a length of600mm,and aluminum reflective film was pasted on the internal surface. The ozone productionof UV lamp was between0.25g/h and0.74g/h; its power was between85W and90W,and the light intensity inside the reactor was greater than1.4mW/cm2.Research of ozone catalytic processes showed that honeycomb ceramic wassuitable as a carrier, and manganese dioxide was the best catalyst whose optimal loadingmethod was oxidation hydrolysis. Ozone catalytic conversion rate could be100%atdifferent flow rate, when the height of catalyst layer was40cm.Research showed that, UV sterilization rate reduced with relative humidity(55%-90%), flow rate(1.5m3/min-6.0m3/min) or organic content(0-4%) increasing;when microorganism concentration or light intensity increased, UV sterilization rateincreased. Ozone catalytic sterilization rate reduced with flow rate increasing, andincreased with ozone concentration or relative humidity increasing. Sterilization rate of combined device in the microbial aerosols simulated sceneshowed that forty minutes killing logarithm on Escherichia coli was3.11, and sixtyminutes killing logarithm on spores was3.16under the following conditions: relativehumidity of88%-93%, bioaerosol concentration of105CFU/m3, air flow rate of4.5m3/min. Sterilization rate of combined device in the actual field showed that when theroom size was21m3and37m3, the killing rate on natural bacteria was greater than90%after sixty minutes and ninety minutes.