Study On The Performances And Mechanisms Of UVA-LED Hybrid With Electrochemical Inactivation Of Microorganisms In Water

Water shortages and water pollution problems have become increasingly serious as the population continues to increase.In particular,microbial pollution poses a serious threat to people’s health,so it is very important to develop efficient and clean disinfection technology.This paper studies the water disinfection performance and mechanism of the UVA-LED and electrochemical disinfection process.The specific research is as follows:1.UVA-LED synergizes with dissolved oxygen electroreduction to generate H₂O₂ in situ and significantly improves the UVA drinking water disinfection process.The initial concentration of UVA-LED（λ=365 nm）to completely inactivate E.coli is 10⁶ CFU/m L,and the required processing time is reduced from 180 min to 80 min.As a result,the total energy consumption required for complete bacterial inactivation is reduced from 43200 J/L to 20196.4 J/L,saving 53.25%of electricity.It’s conducive to increase light intensity and water temperature for drinking water disinfection.In addition,it’s can be promoted the progress of the electrochemical reaction by increasing the dissolved oxygen concentration or increasing the current density during the disinfection process,which improve the disinfection efficiency.The quenching experiment combined with electron paramagnetic resonance（EPR）detection showed that a variety of reactive oxygen species（ROS）can be generated in the UVA-LED synergistic H₂O₂ disinfection process,so as to achieve high-efficiency drinking water disinfection.And ¹O₂play a primary role.Under the photoelectric synergy,the integrity of E.coli is destroyed.UV light and in-Fenton cause DNA damage and reduced enzyme activity,thereby killing E.coli compared with UVA disinfection completely,and co-processing destroys cells more thoroughly.It’s a drinking water treatment technology with low energy consumption and high efficiency.2.Compared with neutral electric Fenton,UVA neutral electric Fenton has stronger disinfection performance.Compared with UVA disinfection and neutral electric Fenton disinfection,UVA neutral photoelectric Fenton reduces the energy consumption for complete inactivation of microorganisms by 64.3%and 68.75%respectively,which significantly reduces disinfection costs and shortens disinfection time.The irradiation intensity was increased from 1.2 W to 3.6 W,and the treatment time was reduced from 50min to 30 min.Under aeration conditions,the inactivation rate of Escherichia coli was increased by 50%.The study found that when the ratio of Fe:NTA is 1:3 and the initial Fe²⁺concentration is 30 mg/L,the wastewater disinfection efficiency is the best.In the secondary wastewater treatment process of a municipal sewage treatment plant,it takes 50minutes to completely kill E.coli with an initial concentration of 10⁶ CFU/m L.The higher initial concentration of bacteria,the larger the volume of water to be treated,and the processing time required longer.In the UVA neutral photoelectric Fenton disinfection process,¹O₂,·OH and·O₂^-all play an important role,and·OH is particularly significant.The carbon center free radicals produced by the degradation of NTA and the oxidation of dissolved organic matter in the actual wastewater can promote the disinfection process.In the process of UVA neutral photoelectric Fenton,the DNA of E.coli is degraded and its cell integrity is severely damaged,so as to achieve the purpose of killing microorganisms completely.This paper studies the addition of electrochemical synergistic disinfection on the basis of ultraviolet disinfection.It promotes the production of a variety of active oxygen clusters,which can strengthen the destruction of the cell interior and cell structure.This paper results in the permanent inactivation of E.coli and reveals UVA and electrochemical disinfection high efficiency performance of synergistic water treatment.