Study On The Catalytic Inactivation Of Escherichia Coli By Carbon Supported Metal/heteroatomic Composites

The safety of water is related to human survival and well-being.Serious water pollution is one of the main causes of abnormal human death.In this case,E.coli is the main pathogenic microorganism that causes the biological pollution in the water,and the exploration of the method that can effectively kill E.coli becoming an important hot issue.In numerous research reports,the catalytic free radical sterilization shows excellent performance.Free radicals have the characteristics of high oxidation performance,high sterilization efficiency,and short action time,almost no secondary pollution.Activating free radical sterilization method can efficient,simple,economical and safe to kill E.coli,which has become a hot research hotspot.However,the compound catalytic materials for the catalytic oxygen free radical inactivated E.coli still has several defect such as high cost,low efficiency,low free radical yield,and the fuzzied mechanism of sterilization.Based on these,this study esplore the effect of the carbon metal/hybrid atomic composite material to stimulate free radical,and the possible mechanism of generating free radical is based on the effect of the bacteria and the performance of various properties.（1）In general,stimulating free radicals need to add additional energy（such as light,electricity,heat,etc.）or oxidizing,which is expensive and difficult to practice.Therefore,there is an urgent request to find a free radical generation method that does not need to supply the outside world.Catalytic materials with high reduction activity can catalyze O₂/H₂O to generate free radicals,which is a promising strategy for inkilling bacteria with low cost.Based on this,a double catalytic composite(C_IDS@CFO@F⁰C⁰),which is composed of cobalt and its alloyed loaded onto porous carbon.The detailed crystalline structure of the double catalytic fungagent C_IDS@CFO@F⁰C⁰ can be found that the composite materials contain cobalt and cobalt-iron,which means that the composite materials contain two different types of transition metal and cobalt:Fe⁰/Fe²⁺/Fe³⁺and Co⁰/Co²⁺/Co³⁺.The two most active,multi-valent transition metals can form several oxidation reduction pairs,triggering the activation oxidation of O₂/H₂O,generating a large number of the·OH and·O₂^-free radicals.The effect of the study on the effect of the sterilization of the bacteria was found to have a great effect on the removal of E.coli.On the contrary,light conditions have essential nought an effect on the reaction.After the reaction parameters are optimized,the double self-catalyzed material can eradicate E.coli completely in two hours.The EPR spectrum analysis shows that the dual catalytic materials can stimulate free radicals.Meanwhile,it was found that the·OH was a dominant role in the sterilization process,and the·O₂^-also had an effect.In general,the dual catalytic system is a way of low cost and efficient sterilization without additional energy or reactive oxygen.（2）In order to reduce the cost of the metal catalytic system in the above research,the carbon nano-composite catalytic materials are prepared by waste.This study used Fe/Mo/Mg O as a catalyst for the preparation of carbon nanocomposites and catalytic generation of free radicals.The structural quality of CNT@FM@Mg O(carbon nanotubese and its effect and mechanism were studied.The production of carbon nanotubes in composite materials and the composition of the catalysts were analyzed by means of tpo-ramaner xrdand sem and sem.It can be found that CNT@FM@Mg O can remove E.coli in two hours,confirming that it is a composite material to sterilized bacteria efficiently.At the same time,the stability and repeatable experiment of the material was found that seven times the sterilization fruit remained 100 percent.It is suggested that the composite materials have good stability due to the covered carbon nanotubes with internal catalysts,improving the stability of the material.By studying the bacterial mechanism of the compound material CNT@FM@Mg O,the electron transfer of the catalyst promotes the formation of the free radical·OH and·O₂^-,and the carbon nanotubes protect the catalyst well and the oxidation reduction is also produced to form ¹O₂and·O₂^-,which further improves the efficiency and stability of the material.This study further reduces the cost of composite catalytic materials,and provides a feasible solution for the treatment and utilization of discarded plastics.（3）Metal catalysis is a way of effectively reducing costs and catalyzing free radicals.However,the metal is difficult to be biodegradable,which is harmful for practical applications.In this paper,the non-metal composite materials were used to catalyze the production of free radicals.This study successfully synthesized a non-metallic photosensitive composite B@RP to effectively remove E.coli.The results of the xrdand XPS confirm the required red phosphorus and carbon matrix in the composite catalytic materials.And EPR and heat imaging showed that the red phosphorus photocatalytic and photothermal characteristics of the rice shell biochar were significantly improved.B@RP can achieve 100%removal efficiency in 2h,exhibiting high efficiency and sterilization performance.The possible sterilization mechanism is that the photothermal effect can change the permeability of E.coli cell membrane,causing the B@RP photocatalytic production of the·OH and·O₂^-into the cell,which can improve the removal of efficiency significantly and the target of efficient sterilization can be got.In addition,the material has good stability and cycling performance,maintaining 100%effect even after nine sterilization experiments.The more noteworthy is that red phosphorus and rice shell biochar are environment-friendly composite photocatalytic materials because they do little harm to the environment.Therefore,the study of non-metallic photosensitive composite B@RP provides a new idea for photocatalytic sterilization.The purpose of this study is to prepare composite materials with low cost and high catalytic sterilization.Based on the construction of metal and nonmetal catalytic systems,three kinds of compound catalytic sterilizing materials excited free radicals in different ways were successfully synthesized.The physicochemical properties of the composites were characterized by XRD,SEM,FT-IR,BET and XPS.In the material sterilization experiment,the killing effect of three kinds of composite materials on escherichia coli was clarified.Based on the known properties of the composite material and the enzyme activity test of E.coli,the possible bactericidal mechanism was speculated.This study provides a new reference scheme for efficient removal of harmful microorganisms in water.