Study On The Influence Of Ambient Temperature/Humidity On The Photocatalytic Degradation Process Based On The Automatic Analyzer Of Paper-making Polluted Gas

With the continuous and rapid development of China's economy,the environmental problems become more and more serious,and the air pollution problem is also increasingly prominent.The pulp and paper industry has become the sixth largest pollution industry in the world.The main pollutants are gaseous,solid and liquid.At present,most domestic and foreign research focuses on solid and liquid pollution,and the research of paper making pollution gas is very few.There are many kinds of polluted gases in the paper industry,mainly including formaldehyde,benzene,hydrogen sulfide and sulfur dioxide,which are harmful to the human body.At present,most of the existing gas detection devices in China are gas chromatograph,but they do not have a complete sample collection and preprocessing system,which can only realize the off-line analysis,resulting in the cumbersome and time-consuming process of sample processing and detection.In view of this situation,we have designed and developed a automatic analyzer for paper-making polluted gas.The development of the automatic total analyzer for paper making pollution gas is based on the STM32F407ZET6 MCU as the main control chip,with microchip micro control technology as the core,using a variety of gas sensors to detect all kinds of polluted gases,realize the real-time detection and display of the polluted gas,record and analyze all kinds of gas concentration data detected by the connection with the upper computer,and can draw gas at the same time.The trajectories of dynamic changes of body concentration facilitate data storage and analysis and processing of later experimental results.In the experiment of the performance test of the automatic total analyzer for paper polluting gas,we find that it has good performance and can reach the needs of the experiment.At the same time,two different paper factories in Guang dong have been tested on the spot,we detect the kinds and concentrations about the different polluted gases.In the previous experiment,it was found that ambient temperature/humidity had a certain influence on the photocatalytic degradation process.Combined with the existing photocatalytic degradation system,formaldehyde,benzene and hydrogen sulfide were used as the target pollutants,by changing the temperature and humidity of the detection environment,we explore the influence of ambient temperature/humidity on photocatalytic degradation of different polluting gases.In the experiment,we find that the photocatalytic degradation of formaldehyde,hydrogen sulfide and benzene all accorded with first-order kinetics.Among them,ambient humidity has a great inhibition effect on photocatalytic degradation of formaldehyde.With the humidity in the range of 34%-53%,with the increase of humidity,the photocatalytic degradation rate gradually decreases,and the first order reaction kinetics constant of formaldehyde photocatalytic degradation is reduced from 0.0657 min^-1 to 0.0196 min^-1.On the contrary,ambient humidity has a promotion effect on photocatalytic degradation of hydrogen sulfide:the rate of photocatalytic degradation of hydrogen sulfide is accelerated with the increase of humidity in the range of 33%-60%,and the kinetic constant of first order reaction of hydrogen sulfide photocatalytic degradation increases from 0.0322 min^-1 to 0.0551min^-1.In a certain range,the photocatalytic degradation of benzene is accelerated with the increase of ambient humidity.When the ambient humidity is more than 40%,the photocatalytic degradation rate of benzene decreases with the increase of ambient humidity.When the humidity rises from 33%to 41%,the kinetic constant rises from 0.0458 min^-1 to0.0674 min^-1,and the kinetic constant decreases from 0.0674 min^-1 to 0.0361 min^-1 when the humidity rises from 41%to 60%.The effect of ambient temperature on the photocatalytic degradation of formaldehyde,hydrogen sulfide and benzene is very small.Within the range of25-40?,the kinetic constant of the first order reaction of formaldehyde photocatalytic degradation is about 0.025 min^-1.The first order kinetic constants of the photocatalytic degradation of hydrogen sulfide and benzene are about 0.04 min^-1,not related to the ambient temperature.