Study On The Kinetic Of The Formation Reaction Of High-purity Chlorine Dioxide Gas And Its Sterilization Effect To Microbe

It is the most effective countermove to exploit the highly active germicidal agentagainst the lethality of biological weapon.ClO₂ gas has attracted attention in the views ofbroad spectrum and highly active bactericidal ability and few or none poisonous byproducts.In this paper,the formative technology of high-purity ClO₂ gas,kinetics of its reaction andbactericidal effect were studied.(1) Study on the generation of high-purity ClO₂ gas and the determination of itsconcentration and purityA new technology used the NaClO₃-NaClO₂ compound mode to generated ClO₂ gas wasset forth.The reaction of HCl and NaClO₃ was proceed in main reactor,and,the generatedgaseous mixture containing Cl₂ and ClO₂ enter into the fixed bed reactor loaded NaClO₂granule,where Cl₂ was inverted into ClO₂,and the ClO₂/Cl₂ is 60/1 approximately in the endproducts,the purity of ClO₂ was up to 98.19%.The colorimetric card and test cardcorresponding to concentration of ClO₂ rapid determination were prepared,and the errorpercentage was less than 10% in test specification 5～1000mg/L.(2) The kinetics of the formation reaction of high-purity ClO₂ gasThe mechanics hypothesis about chemical reaction of HCl and NaClO₃ was set forth,andbeen verified furtherly.The fixed bed and equivalent particle model was established bymicrostructure analysis of gas-solid reaction of NaClO₂ and Cl₂,and the reaction kineticsmodel,using NaClO₃-NaClO₂ compound technology to generate high-purity ClO₂ gas wasobtained.(3) The explosion characteristics and mechanics of ClO₂ gasIt was the first time for the explosion characteristics of ClO₂ gas was studied in acylindrical exploder with a shell capacity of 20 liters.The impact of concentration toexplosion limit,explosion pressure and induction time were determinated.The experimentalresults indicated that the lower concentration limit for the explosive decomposition ofchlorine dioxide gas was 9.5% ([ClO₂]/[air]),the upper concentration limit was 100%,and thepressure of explosion increased with increasing concentration of ClO₂ gas,the induction time(the time from the moment of sparking to explosion) to attain the maximum pressure of explosion was shorten with increasing concentration of ClO₂ gas.The explosion reaction styleof ClO₂ is decomposition,the reaction mechanism of ClO₂ is of a degenerate chain-branchingtype involving the formation of a stable intermediate Cl₂O₃,and it is the major factor toinitiating and accelerating branched chain reaction.(4) System device for generating high-purity ClO₂ gasFollowing the principle of safety,the reactor to generated high-purity ClO₂ gas wasprepared.The production capacity of ClO₂ gas attained 1.5kg/batch,the percent conversion ofNaClO₂ and NaClO₃ were up to 93.7% and 95.5% respectively,the productive rate of ClO₂gas attained 97.3%,its purity was more than 98.55%.The optimum reaction time range wasfrom 30 to 45 minutes,the deviation of ClO₂ yield between theoretically,and,actually,was nomore than 6.2%,but the deviation of actual output to computing result by dynamics methodbecame more and more when the reaction time exceed the optimum range.(5) Research on the application of ClO₂ gasa Effect of ClO₂ gas on bactericidal and keep fresh on grapeThe regularity of sterilization to Staphylococcus Aureus,Escherichia Coli 0157.H7,Listeria Monocytogenes and Saprophytic Yeast on grape surface with ClO₂ gas were studiedin this paper.The result showed that the bactericidal effect was markedly increased alongwith the concentration increased of ClO₂ gas and the bactericidal time in the experiment range.When the ClO₂ gas concentration 25mgl^-1,bactericidal time 12min and temperature 25℃,Staphylococcus Aureus,Listeria Monocytogenes and Saprophytic Yeast decreased more than6.41og,but the decrease of Escherichia Coli 0157:H7 attained 5.761og.There exist synergismeffect between the bactericidal time and ClO₂ concentration.The result also showed that itwas best condition for grape to keep fresh when the concentration of ClO₂ gas is 30ml/m³,ClO₂ gas can inhibit effectively methionine catabolic process decrease,the generating ofethene when killing the Saprospira on the surface of fruit and vegetable,so it is useful todelay metamorphic process,reduce nutritional ingredient loss,and keep the fruit andvegetable fresh for a long time.b The municipal wastewater disposal by ClO₂The result showed that the sterilizing effect to bacillus coli was increasing with theconcentration of ClO₂ and the treating duration increasing,the optimum were ClO₂concentration 5mg/L and bactericidal time 20min,the bactericidal ratio to bacillus coli was99.99%,which is limit bactericidal limit.After wastewater disposal,the CHCl₃ had not been detected in the water,the content of ClC₄ existed difference in some degree with the differentClO₂ concentration,but the real content is lower.The results indicate that the content ofhalogenated hydrocarbon are less than other common chlorine disinfectors after wastewaterare disposed by ClO₂,therefore,environment security is enhanced by using the ClO₂ gas tosterilized recycle-water.