Study On The Preparation And Germicidal Efficacy Of Electrolyzed Water With Rich Active Nitrogen Germicidal Factors

With the development of food industry technology,the food safety problem has attracted more and more attention.Therefore,low-cost,environment-friendly and broad-spectrum antimicrobial agents become a hot hot research topic.acidic electrolyzed water as a simple and environment-friendly fungicide has been well performed in the fields of sterilization,vegetable and fruit preservation and other fields,among which the main acting component is active chlorine.This paper plans reactive nitrogen species and reactive oxygen species components were introduced by plasma activation techniques to explore the coupled bactericidal effect of the three active components.（1）First,optimizing the acidic electrolyzed water preparation,improving the electrolysis efficiency of the electrode,and efficiently obtain the oxidative electrolysis water containing a high available chlorine concentration.Oxidation of Cu on the surface of RuO₂samples by magnetron sputtering and thermal decomposition yields the RuO₂@Cu O electrode.Compared with the RuO₂electrode,the chlorine evolution activity of the RuO₂@Cu O electrode increased significantly,and the oxygen evolution activity decreased slightly.At a current density of 100 m A cm^-2,the most obvious enhancement of chlorine evolution activity was RuO₂@Cu O-3,its chlorine evolution potential was reduced by 40m V,and the oxygen evolution potential was increased by 18 m V.The CER mechanism of RuO₂@Cu O electrode is the electron transfer step,and the OER mechanism is the formation and transformation of OHads.SEM,XRF,and XRD representations all showed extremely low loading of Cu,and XPS representations showed that the Ru⁴⁺/Ru³⁺3p_3/2tracks of the RuO₂@Cu O electrode showed a positive shift of 0.3 e V compared to the RuO₂electrode.The modification of the trace Cu oxide significantly increased the chlorine evolution efficiency of the RuO₂electrode.The electrolytic efficiency of the RuO₂@Cu O-3electrode was increased by 236%compared to the RuO₂electrode.Compared with the RuO₂ electrode,the acidic electrolyzed water prepared by the RuO₂@Cu O-3 electrode increased the killing values of E.coli suspension and B.subtilis suspension by 2.95 and2.38 log₁₀CFU/m L,respectively.（2）Secondly,on the basis of the efficient preparation of acidic electrolyzed water,the reactive nitrogen is introduced into the acidic electrolyzed water by plasma activation to obtain the plasma-activated oxidized-electrolytic water rich in reactive nitrogen（Plasma-activated acidic electrolyzed water,PA-AEW）.Discuss the exact methods to accurately determine the H₂O₂,NO₃^-,NO₂^-and HCl O content in PA-AEW.According to the reduction of the NO₂^-content in the range of 105 to 116 mg L^-1,the H₂O₂content in the range of 0 to 0.43 mg L^-1,and the content of HCl O from 16 mg L^-1to 3 mg L^-1,cross-reaction occurred between reactive chlorine,reactive oxygen species and reactive nitrogen species occurred.Among them,the active chlorine reactive oxygen species was in the range of 0.29 to 16 mg L^-1,and the reactive nitrogen species was in the range of 80 to326 mg L^-1.The activated short-lived species O₂NOOH and unelectrolytic Cl^-reactions in electrolytic water can generate HCl O and NO₃^-.The sterilization results showed that PA-AEW sterilized B.subtilis suspension significantly better than the RuO₂@Cu O electrode（P<0.05）,and the characterization results of fluorescence and electron microscopy and scanning electron microscopy also confirmed that PA-AEW destroyed the integrity of B.subtilis.The comparison between PA-AEW and PAW,and the standing evaluation of PA-AEW showed that the active chlorine ingredient in solution was converted to the active nitrogen component to produce a more active（short life）bactericidal factor.This factor exerted a major bactericidal activity,which reduced the log killing value of PA-AEW against B.subtilis suspension by 3.26 log₁₀CFU/m L within 0.5 h.（3）Finally,on the basis of preparing activated water,introduction of reactive nitrogen oxygen into plasma activated water by electrolysis,Electroelectrolytic Plasma Activated Water is obtained and maintains high redox potential above 1100 m V.It was found that the electrolytic time was 0 min,the content of HCl O in the electrolyte is 1.9 mg L^-1,which further confirms O₂NOOH and Cl^-will generate HCl O and NO₃^-.When the electrolysis time was greater than 80 min,the mass fraction of sodium chloride was greater than 0.15%,and the electrolytic current was greater than 200 m A,the killing value within10 s was greater than 3 log₁₀CFU/m L（P<0.05）.The same preparation level PA-AEW and E-PAW sterilized E.coli biofilms more than 4.37 log₁₀CFU/m L,sterilized B.subtilis biofilms was 4.11 and 4.41 log₁₀CFU/m L,both better than same preparation level AEW and PAW（P<0.05）.It embodies the synergistic bactericidal effect between the reactive chlorine component and the reactive nitrogen and oxygen component.Therefore,E-PAW and PA-AEW systems not only combine the three active components of active chlorine,active oxygen species and active nitrogen,but also show a very good synergistic bactericidal effect between active nitrogen and active chlorine,which successfully prepared the highly efficient oxidative electrolytic water rich in active nitrogen bactericidal factor.