Experimental Studies On Killing Space Harmful Microorganisms By Hydroxyl Radical

Harmful Microorganisms in space have become a major threat to the health of human and the survival of propagation.They transmit by contact and by air.So killing harmful microorganisms in the air and on the surface is particularly important and urgent.In fact there is no effective way to fast,effective and nonpolluting eliminating harmful microbes to prevent the spread of the epidemic.Because killing harmful microorganisms by hydroxyl radical(·OH) possesses following advantages:fast, nonselective,effective,nonpolluting.It makes up for the shortcomings of the conventional methods.However there are many problems in·OH producing methods. In this thesis,strong ionization discharge plasma technology is used to produce high concentration of·OH solution,which solves the problem of production in scale and other issues,to meet the needs of practical applications.·OH solution is sprayed on the surface with typical bacteria,fungi or spore in sterilization experiments.The results show that·OH solution is a nonselective and efficient and fast and green sterilizing agent,which can be employed satisfactorily in broad areas.The effects of operating conditions on sterilization are discussed and analyzed,and the order is:spraying density＞·OH concentration＞action time.And the optimal operating parameters have been obtained:spraying density 21μl/cm~2, threshold concentration of·OH solution=1.0 mg/l and action time=4 s.So sterilization technology using·OH solution can meet the requirement of high efficiency and less use level and rapid sterilization.Under the suitable conditions,·OH solution can further act on cellular relict,which leads to complete disappearance of microorganism.The principium of elimination is expounded that·OH can react with important components and functional materials of the cell wall,cell membrane and the intracellular material to undermine the basic structure and function of cells,resulting in the death of microorganisms.On the basis of experiments,observation and analysis of the mentioned mechanism,the sterilization process using·OH is analyzed and described preliminarily as follows:(1)·OH damages cells from outside.(2)·OH acts on cell wall and cell membrane of bacteria and fungi to cause damage to the integrity of its structure,and then bring the cell to rupture;also·OH destroys carcasses,cortex, membrane and wall of spores.(3) Then intracellular substances leak,and quickly disappeared.(4) Large membranes contract into spherical surface under surface tension. (5) Surplus·OH disappears by reacting with cellular relict or decompose.·OH solution could well exterminate bacteria,fungi and spores on surface,and don't bring secondary pollution,which lays the foundation for air sterilization and space sterilization.