| Freshwater resources are also one of the basic material resources on which human society depends for survival and development.However,with the continuous expansion of the scale of industry and agriculture and the rapid increase of the population,the supply of conventional water resources such as surface water and underground water is increasingly strained worldwide,and the contradiction between supply and demand of fresh water resources is increasingly intensified.How to realize the utilization of unconventional water resources such as seawater and brackish water is the key to solve the water crisis thoroughly.At present,the utilization of unconventional water resources faces two core problems,namely,low cost desalination and continuous water sterilization.The existing technology has some problems,such as high equipment cost,high energy consumption,large equipment volume,low water utilization rate,secondary pollution and so on,which make its practical application limited.At the same time,the traditional water sterilization technology(such as high temperature sterilization,UV sterilization,fungicide sterilization,etc.)is faced with high energy consumption,secondary pollution and process is difficult to be continuous and other problems,resulting in its large-scale application is limited.Therefore,the development of new low-cost seawater desalination and sterilization technology is of great significance to alleviate the crisis of fresh water resources and ensure the safety of drinking water.Electrochemical deionization(EDI),as the product of Capacitive deionization(CDI)technology development and innovation,with its advantages of high energy efficiency,high water efficiency,no secondary pollution.It is expected to become one of the most effective desalination technologies in the 21st century,which is highly valued by governments and research circles,and its potential is highly noticed.However,in the development process of EDI,researchers also found some problems.For example,compared with traditional CDI,the desalination capacity of EDI system has been significantly improved,but its desalination rate has not been improved,which makes it difficult to give full play to its advantages of high capacity.At present,most studies focus on Na+trapping cathode materials,while few studies focus on Cl-trapping cathode materials.At present,there are only a few studies on silver series and bismuth series,etc.On the other hand,water sterilization is an important link in the resource utilization of natural water(seawater,brackish water,etc.).With millions of people dying each year from diseases related to water-borne pathogens,sterilization of water is also an important part of ensuring safe drinking water.However,due to the traditional high temperature sterilization and ultraviolet sterilization due to equipment scale limitations and high energy consumption problems can not be applied on a large scale,at the same time,the sterilization method of fungicide will inevitably cause secondary pollution of water bodies.Capacitive deionization disinfection(CDID)is a new water disinfection technology emerging in recent years.Its principle is to realize the removal and killing of bacteria through electric adsorption and contact sterilization.Because of the advantages of fast sterilization rate and continuous process,CDID quickly attracted the attention of the industry.However,the prominent problem facing CDID at present is the imbalance between its sterilization and adsorption rate,as well as the fast adsorption and slow sterilization,which can easily lead to the re-desorption of bacteria and secondary pollution,which has become the biggest obstacle to its practical application.In view of the technical defects of EDI and CDID,such as low desalination rate,lack of research on positive electrode,poor cycling stability and sterilization material limitation,this paper tries to solve them by taking advantage of the outstanding advantages of the new MNCs material that are significantly different from the traditional nanomaterials.The specific contents are as follows:1)Aiming at the problem of insufficient desalination rate of EDI technology,this paper prepared ultra-small MoC nanocluster loaded carbon nanofibers(MoC@CNF)and Bi OCl loaded carbon nanofibers(Bi OCl@CNF),respectively.Dual-ion electrochemical deionization(DEDI)system was constructed as negative electrode and positive electrode respectively.The results show that the MOC clusters in our synthesized MoC@CNF have an ultra-small size,up to less than 30 nm.At the same time,based on MoC@CNF||Bi OCl@CNF DEDI system in exhibit high desalination capacity(80.86 mg g-1)and cycle stability(30 cycle only 12%)at the same time,the desalination rate reached a high of 0.38 mg g-1 s-1,Compared with other DEDI systems,it has obvious advantages.However,it was found that the relatively large size and relatively weak stability of cathode materials greatly limited the desalination performance of the desalination system.2)In view of the problems of insufficient research on cathode materials and poor cycling stability,this paper starts from the low-cost Cl-trapping material Bi,takes MOF material as template,and obtains ultra-small Bi nanocluster embedded carbon nanobundles(Bi NCs@CNBs)through temperature control carbonization.Rock-chair CDI(RCDI)system was constructed using it as electrode material.The results show that the size of Bi clusters in Bi NCs@CNBs complex is significantly affected by carbonization temperature and decreases to less than 2 nm at the highest temperature of1000?.The size of Bi NCs has a significant effect on the capacitance of Bi NCs@CNBs(the capacitance increases with the decrease of the size of Bi NCs),and the surface contribution in the total capacitance increases significantly with the decrease of the size of Bi NCs.The desalination rate of RCDI system based on Bi NCs@CNBs electrode is extremely high,reaching 0.53 mg g-1 s-1,and the system has excellent cycle stability,which only decreases by 10%after 50 cycles.3)In order to solve the problem of the mismatch between bactericidal kinetics and adsorption kinetics,MOF-Ag NCs-PPy nanocomposites were prepared in this paper using porous material MOFs as the matrix and Polypyrrole nanotube(PPy NT)as the conductive material.The MNCs have mocking nanoscale size.It can increase the contact area with bacteria and improve the sterilization efficiency.Capacitor sterilization is used to add a specific voltage to the device,and bacteria are adsorbated on the surface of the positive electrode and contact with the sterilization material to realize the purpose of sterilization.After power off,bacteria desorption can be realized and then the purpose of recycling sterilization can be realized.In a Single long time(60min and 5 h)sterilization test,high sterilization rate(99.999%)was obtained within 60min,and sterilization(91%)efficiency remained after 5 h.The composite based on silver nanoclusters and MOFs effectively improved the cycling stability of the electrode material,and maintained a high sterilization efficiency(?99.99%)after 10 cycles.Germicidal materials should have a broad spectrum.The Galanz positive bacteria(Bacillus subtilis,B.subtilis)and Galanz negative bacteria(Escherichia coli,E.coli)were selected for the test,and the results showed that both had good germicidal properties,which further proved the broad spectrum germicidal properties of the germicidal electrode materials.In addition,the simulation of reagent water sterilization in water with different salt concentration proved that the salt concentration has almost no effect on the sterilization efficiency. |
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