Study On The Preparation And Bactericidal Performance Of Electrolyzed Water Based On Cobalt-based Nanoarray Electrodes

Food-borne pathogenic bacteria would secrete toxic and harmful substances,causing food deterioration,which pose a serious threat to human health.Among numerous widely distributed food-borne pathogens,Methicillin-resistant staphylococcus aureus(MRSA)are highly pathogenic and easily transmissible.At the same time,countries and international organizations around the world have put forward increasingly strict requirements on microbiological testing,and quarantine standards have been constantly improved,resulting in frequent trade frictions.No matter from the point of view of human health,or from the perspective of sustainable economic development,it has become a consensus to develop and promote new pollution-free and residue-free fungicides,hence effectively control microorganisms in food production and processing.Electrolyzed water has been widely used as a bactericide on account of good antimicrobial activity,bactericidal broad-spectrum,low-cost and safety in recent years.Current researchers focus more on the application of commercial electrolyzed water,but the development of electrode materials with lower cost and better catalytic performance is more important for the practical application of electrolyzed water.Nanoarray electrodes have drawn much attention on account of the advantages of high efficiency and energy-saving.Take MRSA as the research object,we designed cobalt oxide nanoarray(Co₃O₄NS/CC)and cobalt phosphide nanoarray(Co P NS/CC)as the anode and cathode of electrolysis system,then investigated the performance of the system to prepare electrolyzed water,as well as the influence of different reaction conditions on the characteristic parameters of the electrolyzed water.Use suspension quantitative germicidal test method to explore the sterilization effect of the electrolyzed water to MRSA.The main achievements are as follows:(1)The Co₃O₄NS/CC and Co P NS/CC were successfully synthesized using the cobalt-based metal organic framework nanosheet array(Co-MOF NS/CC)as the precursor.The morphology and composition of the materials were analyzed by a series of characterization including SEM,TEM,XPS and XRD.Subsequently,it was proved that the Co₃O₄NS/CC and Co P NS/CC had good catalytic activity of chlorine evolution reaction(CER)and hydrogen evolution reaction(HER)through electrochemical methods,respectively,and the catalytic reaction could be carried out vigorously under very low overpotentials.The chronopotential curves of Co₃O₄NS/CC showed that the catalytic performance of the catalyst hardly declined during the catalytic process of 20 h.The multi-step chronopotentiometric curve of Co P NS/CC shows that the catalytic performance is stable and have high mass transfer efficiency.(2)The non-diaphragm single-chamber electrolysis system was constructed,and the prepared Co₃O₄NS/CC and Co P NS/CC were used as the anode electrode and cathode electrode,respectively.Electrochemical methods attested that the system possess efficient electrolytic performance and stability:just needed 2.26 V to reach the current density of 10m A cm^-2,and the potential have no obvious decrease during the catalytic process as long as18 h.The dilute Na Cl solution was electrolyzed through the direct current provided by the electrochemical workstation.The effects of electrolyte concentration,current density and electrolysis time on the characteristics of electrolytic water were investigated.Considering the factors such as bactericidal performance and cost,the suitable range of preparation conditions was determined.(3)Suspension quantitative bactericidal method was used to explore the bactericidal capacity of the alkaline electrolyzed water generated by system with high available chlorine content(ACC)and oxidant reductant potential(ORP).The bacterial strain utilized were purified strains in the laboratory.The results showed that the electrolytic water with ACC of10 mg L^-1could make almost all of the MRSA of 8.88 log CFU m L^-1die within 15 s,having a highly effective lethal effect.SEM and fluorescence microscope images showed the changes of morphology and membrane permeability of bacterial cells after sterilization.