| With the continuous improvement of people's living standards,people put forward higher requirements for interior decoration.However,due to t the large amount of volatile pollutants in the building decoration materials,the indoor air pollution is becoming worse.Therefore,people have an explosive demand for air purifiers.And photocatalytic technology has attracted people's attention due to its environmental protection characteristics.However,there is many problems of low efficiency in photocatalytic technology on the market at present.Therefore,it is especially important to study the modification of photocatalyst and combine photocatalyst with other purification technologies and apply them to air purifiers.In this study,I will use sol-gel method and dip-molding method to prepare photocatalyst.According to the comparative test method,the photocatalysts were tested and studied in the reaction space from the intensity of ultraviolet light,wind speed and catalyst loading.The surface morphology of photocatalyst filter material was observed by scanning electron microscopy.Then the experimental study on the removal effect of gaseous formaldehyde with potassium permanganate as oxidant and loaded on the carrier.Finally,photocatalytic technology(PCO),activated carbon fiber(ACF)and potassium permanganate alumina balls(PM balls)were used to degrade formaldehyde.The results of various studies show that:(1)The optimum operating conditions of the photocatalyst prepared by sol-gel method are as follows:?=254nm and light intensity of 114?w/cm~2 UV lamp,wind speed of2.9m/s,catalyst loading of 9.5mg/cm~2.According to the test results,the rate of degradation of formaldehyde could reach 100%in the reaction space of 1 m~3 after 9 minutes.And the rate of degradation of toluene was 91%after 60 minutes.The optimum operating conditions of photocatalyst prepared by dip-molding method are as follows:?=254 nm and light intensity of 114?w/cm~2 UV lamp,wind speed of 2.9 m/s,0.15%Ag doped P25 and catalyst loading rate of 16%.According to the test results,the rate of degradation of formaldehyde and toluene was 53%and 20%respectively in the reaction space of 42 m~3.It was found some things when both photocatalysts were used to degrade the same multi-component pollutants.At the same time,both photocatalyst were in accordance with the single molecule L-H model.(2)The study of potassium permanganate oxidant showed that the degradation of formaldehyde by PM balls followed the first-order reaction kinetics equation.The primary pass rate of formaldehyde was between 21.88%and 69.33%when the air volume was300m~3/h.The degradation rate of formaldehyde in the reactor can be significantly improved when the amount of PM balls is above 1.25kg.(3)The degradation of formaldehyde was test by combining photocatalytic technology with activated carbon fiber and PM balls.The study found that the highest the rate of degradation of formaldehyde was 94%by ACF+PCO within 1h.It was 15%faster than the rate of degradation of formaldehyde by ACF+PCO+PM balls.At the same time,the CADR value and EER value were used to evaluate the air purifiers of different technologies.It was found that the efficiency of purifier was level 5 when the purifier only used tubular photocatalyst technology.And the removal efficiency of other technologies for gaseous pollutants had more than level 4.The ACF+PCO and 5kg PM balls were both level 1 performance.(4)It was proved that the position of each equipment was reasonable in the reaction space by simulating the air distribution in the reaction space.The detector has high reliability for real-time monitoring data of pollutant concentration.It also showed that the air distribution was the most uniform in the whole room when the air purifier was located in the center of the room.At this time,the purification rate of the pollutants is the highest. |
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