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1、电化学技术与环境保（Electrochemical technology and environmental protection）Documents from the network, I collected, finishing, and if there are omissions, errors, but also please correct me!Electrochemical technology and environmental protectionEnvironmental protection is a problem that people care about ver
2、y muchElectrochemical technology plays an important role in the development of environmental protection technologyThe advantages embodied in the environmental protection process are as follows(1) environmental compatibility is high. Clean and effective electrons are used as strong redox reagents in
3、electrochemical technologyIs a basic pollution-free green production technologyBecause of the high potential gradient in the interfacial electric fieldA catalyst that corresponds to heterogeneous reactionsTherefore, it is possible to reduce the environmental pollution caused by the addition of a cat
4、alystdyeAt the same time, the electrochemical process has higher selectivityPrevents the formation of by-productsPollutant reduction(2) multifunctional electrochemical process has the functions of direct or indirect oxidation and reduction, phase separation, concentration and dilution, biological ki
5、lling, and so onCapable of handling slightly increased to 1 * 106L of gas, liquid and solid contaminants(3) high energy utilization compared with some other processesThe electrochemical process can be carried out at a lower temperatureIt is not subject to the Kano cycleHigh energy utilizationBy cont
6、rolling the potential, the electrode and the electrolytic cell are designed reasonablyReduce energy loss(4) economical and practical equipment and easy operationLow costThe contribution of electrochemical technology to environmental protection is manifoldThe author makes a comprehensive survey on th
7、e prevention of environmental pollution, the treatment of environmental pollution and the environmental monitoring from the perspective of electrochemical technology1 electrochemical technology and environmental pollution prevention1.1 chemical power supplyA chemical power supply is a device that co
8、nverts chemical energy directly into electrical energy in an electrochemical mannerThe traditional way of transforming energy is the heat engine processHowever, the heat engine process is limited by the Kano cycleNot only energy conversion efficiency is low, resulting in waste of energyAnd produce a
9、 large number of dust, carbon dioxide, nitrogen oxides and sulfur oxides and other harmful substances and noiseCause pollution of the atmosphere, water, soil, etcIt is an important part of environmental protectionCompared with the heat engine processChemical power supply has the advantages of high e
10、fficiency, cleanness, economy and safetyAfter more than 100 years of developmentChemical power supply has been widely used in aerospace, motor vehicles, large power plants, mobile communications, household appliances and other fieldsthereforeChemical power has contributed greatly to the protection o
11、f the environment and the pressure of pollution abatementThe chemical power supply can be divided into 3 main types according to the mode of preservation of active substances: primary batteries, two batteries (accumulators) and fuel cellsBecause the primary battery is not easy to recycleWith the env
12、ironmental protection and conservation of the earth limited resources requirementsIn recent years, research focuses have been placed on two - and fuel cell researchThe original primary battery also switches to the two batteryLead acid battery is the traditional two - time battery used for a long tim
13、eAt present, the utility model has the disadvantages of low energy consumption, slow charging speed and short service lifeBut its cost is lowThe improvement of lead-acid batteries is being studied deeplymeanwhileNew types of batteries have been developed rapidlyThe new type of battery develops towar
14、ds the specific power, large specific energy, long life, safety and low costSuch as Cd/, Ni batteries, MH/Ni batteries, Na/ S batteries, Li/ Ion batteries, Li/ Polymer batteries, Zn/ air batteries, etc.The performance of various battery systems is shown in Table 1Fuel cell has the advantages of high
15、 efficiency, environmental friendliness, quiet and high reliabilityFuel cell electrolyte can be divided into 5 categories: alkaline fuel cell (AFC), proton exchange membrane fuel cell (PEMFC), sulfate (PAFC) fuel cell, molten carbonate fuel cell (MCFC) and solid oxide fuel cell (SOFC)Performance is
16、shown in Table 2Fuel cells are widely usedBoth for centralized power generationCan also be used in a variety of decentralized power supply and mobile power supplyProton exchange membrane fuel cells can be activated quickly for a few seconds at room temperatureIts working current density can reach 14
17、 A, cm- 2Specific power 011 012kW, kg - 1The energy conversion rate can reach 40% 50%thereforeIt is the best choice for electric vehicle, submarine power source and all kinds of movable power supplyAt present, the research of proton exchange membrane fuel cell has become the mainstream of fuel cell
18、researchEspecially for proton exchange membrane fuel cells with methanol as fuelSolid fuel cells are particularly suited for construction of large and medium scale power plantsThe total power generation efficiency of the fuel can reach 70% 80%Molten carbonate fuel cells are used to build regional di
19、spersed power plantsThe total power efficiency of the fuel can reach 60% 70%The development of the automobile industry in twentieth CenturyThe number of vehicles in the world has surged to about 600 million vehiclesTherefore, the development and research of pollution-free and zero emission electric
20、vehiclesEven more, two batteries and fuel cells are boomingIt is predicted that.A human civilization based on chemical power is comingChemical power supply will make greater contribution to sustainable development and environmental protection1.2 electrochemical cleaning processThe electrochemical pr
21、ocess requires low reaction conditions and high selectivityNot only the side effects were reducedIt also makes some special chemical reactions possibleIt can realize the recycling of useful raw materialsReduce the production and discharge of pollutants1.2.1 has electromechanical synthesisOrganic ele
22、ctrosynthesis is the transmission of electrons by means of electrodesOxidize or restore an organic substanceWithout the use of chemicals, direct oxidation or reduction of organic compoundsIt is an interdisciplinary subject of electrochemistry, organic chemistry and chemical reaction engineeringIt ha
23、s the advantages of mild reaction conditions (can be carried out at normal temperature and pressure), simple technological process, easy to realize automatic control, high selectivity of products, less by-products, less pollution and no pollutionIs one of the necessary ways of green synthesisIts cal
24、led green industryBased on the advantages of electromechanical synthesis and the serious pollution caused by the traditional chemical synthesis of three wastesThere has been rapid development of electromechanical synthesisMore than 100 organic products have been produced by ElectrosynthesisIn the wo
25、rld, the production of electromechanical composite products has increased from the last few tons to more than 100 thousand tonsForelectrosysthesis of important chemical raw materials production of adiponitrile has long been knownIn the Ce4 + / Ce3 + or Mn3 + / Mn2 + redox medium indirect electro oxi
26、dation synthesis of fluorobenzaldehydesMother liquor can be recycledThe whole process is basically free of pollutantsAgainIndirect oxidation of the acid can be carried out in various oxidation mediums by cathodic indirect electro oxidation, and the important biochemical reagents L - sulfonyl alanine
27、 and epoxide compound are synthesized by paired electrolysis, and 12 - diol compound, an important organic compound such as halogenated alcoholsElectromechanical synthesis technology is widely usedHave broad prospects for development1.2.2 electrochemical water disinfectionThe treatment and preparati
28、on of industrial waste water, domestic sewage, swimming pool water, drinking water and so on involve disinfection technologyThe common disinfection technologies are chlorine disinfection, ozone disinfection and ultraviolet radiation disinfectionChlorine is a good disinfectantHas a strong bactericida
29、l, algae killing effectAnd the price is lowRelatively wide range of applicationsBut the chlorine disinfection technology has the very big deficiencyChlorine disinfection process is not only high riskAnd produce a lot of toxic byproductsFor example: chloroform, carbon tetrachloride and many other car
30、cinogenic substancesIt has great harm to people and environment, and ozone disinfection and ultraviolet radiation have better disinfection effectBut its energy consumption and price are very highThe technique of on-line preparation of disinfectants and disinfection of water has been developedElectro
31、chemical water disinfection can compensate for the shortcomings of the above methodsIt is energy-saving, cheap, free of residue and safeUnder general conditions, for exampleH2O2 can be prepared online by electrolysisIt has very good disinfection effectElectrochemical water disinfection can be made w
32、ith graphite or graphite fiber electrode, metal titanium electrode, porous carbon and SnO2 electrodeElectrochemical disinfection of intracellular auxiliary enzyme A can also be based on Electro adsorption and anodic oxidation1.2.3 other electrochemical processesMembrane assisted electrochemical proc
33、esses such as electrodialysis, electro deionization (ion exchange assisted electrodialysis), and electro flotation and electrocoagulationBy replacing old processes that are hazardous to the environmentWith its clean production processIt plays an important role in environmental pollution protection a
34、nd environmental pollution control (see section 21113)for exampleHigh purity water can be produced by electrodialysis and used in seawater desalination. Electro flotation and electrocoagulation can be used for pretreatment of various waterThe recent development of fast deionization TechnologyIt is a
35、 new process which combines electrodialysis with ion exchange technologyIt is combined with reverse osmosis equipment and has been used in factory feed water preparationDeionization technology not only has high performance price ratioAnd there is no need to use acid or alkali to regenerate chemicals
36、Thereby reducing waste liquid treatment and emissionIt is expected that.In the next few years, about 85% of the industrial water treatment systems will use RO/ EDI Technology2 electrochemical technology and environmental pollution control2.1 liquid phase pollution controlTreatment of 2.1.1 inorganic
37、 waste liquidElectrochemical methods such as electro deposition, electrochemical oxidation reduction and photoelectrochemical oxidation were usedA variety of inorganic waste liquid can be treatedSuch as: toxic heavy metal ions, toxic inorganic salts (including cyanide, thiocyanate), sulfate, sulfide
38、, ammonia and so onElectrochemical treatment of dilute liquid waste containing toxic heavy metals is the most frequently usedMany industries, such as electroplating, metallurgy, printing circuit and development, emit large amounts of dilute waste liquid containing metal ionsIn recent years, the cont
39、ent of metal ions in emission liquid is more and more strictThe traditional method of adding alkali to precipitate metal ions can only make a small number of metal ions such as Cu and Zn meet the emission concentration requirementsAnd there is a lot of pollution to the environmentThis has led to the
40、 development of electrochemical methods for the treatment of dilute liquid metal ionsThe efficiency of electrochemical treatment of dilute liquid metal ions depends on the mass transfer rate of the removed particles, the effective area of the electrode, and the occurrence of side effectsThe structur
41、e and material of the electrode are the main factors that affect the mass transfer rate and the effective area of the electrodethereforeAt present, the technological core and the research direction of the electrochemical method for the treatment of waste liquid containing metals are the design and d
42、evelopment of electrolytic cells with new electrode structures and materialsThe form of electrolyzer can be divided into two dimensional electrode, electrolytic tank and three-dimensional electrode electrolyzerIn view of different pollutants and different production conditionsVarious electrolytic ce
43、lls with different structures have been applied in industrial pollution controlSee Table 3Planar electrodes and rotating cylinder electrodes are the most widely used two-dimensional electrodesThe planar plate electrode electrolyzer has wide range of applicationsThe structure is simpleThe distributio
44、n of potential and current density is evenThe deposited metal contaminants can be conveniently removed from the open cathode at regular intervalsAfter removing sediment, the electrode can be reusedThe disadvantage of a flat plate electrode cell is that it is not suitable for the treatment of dilute
45、solutionsThe rotating cylinder electrode cell has a uniform potential and current density, and a turbulent flow of the solution in the slotTherefore, there is a high mass transfer rate, and the distance between the anode and the cathode is small. The distance between the two electrodes is smallThere
46、fore, the groove occupies little spaceOhmic loss is small, can realize uninterrupted productionThe rotary cylinder electrode electrolyzer is mainly used for the removal or recovery of Fe, Cu, Ag, Cr, Ni and other metal ionsCompared with flat plate electrode electrolyzerThe energy consumption of rota
47、ting cylinder electrode electrolyzer is higherThe electrode of the three-dimensional electrode cell has a large surface areaHigh mass transfer rateCheap electrode materialIt can be produced at low potentialCommon are packed bed electrodes and fluidized bed electrodesThe research on the three-dimensional electrode electrolyzer is focused on the development of new porous electrode materials and new filling materialshoweverFor the time being