Electrochemical technology and environmental protection.doc

1、Documents from the network, it is my collection arrangement, if there are any omissions, errors, please correct me!The electrochemical technology and environmental protectionEnvironmental protection is the people are very concerned about the problemElectrochemistry technology in environmental protec

2、tion technology development plays an extremely important roleIn the environmental protection process reflects the superiority of mainly the following points(1) high environmental compatibility electrochemical technology is used in the clean and efficient electronic as strong oxidation reduction reag

3、entsIs a basic green production technology of environmental pollutionBecause there is a high potential gradient interface in the electric fieldThe electrode is equivalent to heterogeneous reaction catalystAnd thus reduce the possible because of the added catalyst and bring environmental pollutiondye

4、At the same time, electrochemical process has high selectivityCan prevent the by-products generatedReduce pollutants(2) versatility electrochemical process has a direct or indirect oxidation and reduction, phase separation, concentration and dilution, biological damage, and other functionsCan handle

5、 up to 106 l of gas, liquid and solid pollutants(3) high energy utilization efficiency compared with some other processUnder the low temperature during the electrochemical processIt is not limited by carnot cycleHigh energy utilizationBy controlling the potential, reasonable design of electrode and

6、electrolytic cellIn order to reduce the loss of energy(4) economic and practical equipment, the operation is simpleLow costElectrochemical technology for the contribution of environmental protection are manifoldIn this paper, the author from the electrochemical technology for environmental pollution

7、 prevention and pollution to the environment of governance and to the point of view of environmental monitoring for full review1. the electrochemical technology and prevent environmental pollution1.1. chemical power sourceChemical power source is according to the electrochemical methods directly con

8、vert chemical energy to power a deviceA traditional way to human energy conversion is a process engineHowever, limited by carnot cycle heat engine processNot only cause energy waste energy conversion efficiency is lowAnd produce a lot of dust, carbon dioxide, nitrogen oxide and sulphur oxide and oth

9、er harmful substances, and noiseCause such as atmosphere, water quality, soil pollutionIs an important part of environmental protection have to solveCompared with the heat engine processChemical power supply has the advantages of efficient, clean, economic and securityAfter 100 years of developmentC

10、hemical power supply has been widely used in aerospace, motor vehicles, large power stations, mobile communications, home appliances and other fieldssoChemical power supply to protect the environment, ease the pressure on pollution control has made a significant contributionChemical power supply acc

11、ording to active material preservation methods can be divided into three main types: a battery, secondary battery (battery) and fuel cellsBecause the battery is not easy to recycleWith the requirements of environmental protection and saving the earths limited resourcesIn recent years, people will fo

12、cus on secondary batteries and fuel cellsThe original batteries are a conversion to the secondary batteryLead-acid battery is the long-term use of traditional secondary batteryAt present although it has lower than can, slow speed of charging, short-lived shortcomingsBut its cost is lowPeople are imp

13、roved to do in-depth research of lead-acid batteriesAt the same timeThe new battery has been rapid developmentNew batteries to power, or can be large, long life, safe, low-cost directionSuch as Cd/Ni battery, MH/Ni battery, Na/S battery, Li Ion battery, Li/Polymer batteries, zinc/air battery, etcThe

14、 performance of various battery system are shown in table 1Fuel cells with high efficiency, environmental friendly, quiet, the advantages of high reliabilityFuel cell by the electrolyte can be divided into five types: alkaline fuel cell (AFC), proton exchange membrane fuel cell (PEMFC), sulfate fuel

15、 cell (PAFC), molten carbonate fuel cell (MCFC) and solid oxide fuel cell (SOFC)Performance are shown in table 2Fuel cell applicationsApplies to centralized power generationCan also be used in all kinds of scattered power and portable powerProton exchange membrane fuel cell can be a few seconds fast

16、 start at room temperatureThe working current density can reach 1 4 A? 2 cm -Than 011 012 kw power? 1 kg -Energy conversion rate could reach 40% 50%soIt is the electric car, submarine power supply and the best choice for all kinds of mobile power supplyAt present, the study of proton exchange membra

17、ne fuel cell has become the mainstream of the fuel cell researchEspecially for direct methanol as the fuel of the proton exchange membrane fuel cell researchSolid fuel cells especially suitable for the construction of large and medium-sized power stationIts overall power generation fuel efficiency c

18、ould reach 70% 70%The molten carbonate fuel cell application in the construction of regional dispersed power plantTotal fuel efficiency could reach 60% 70%The development of automobile industry in the 20th centuryThat number jumped to about 600 million vehicles around the worldSo based on no polluti

19、on and zero emission electric car research and developmentMore to promote rapid development of secondary batteries and fuel cellsSome predictOn the basis of chemical power source of human civilization is yet to comeChemical power supply will be making greater contribution to sustainable development

20、and environmental protection1.2. electrochemical cleaning processElectrochemical process requirement is not high on the reaction conditions and high selectivityNot only reduce the side effectsMight make some special chemical reactionIt can realize recycling useful materialsReduce pollutants and emis

21、sions1.2.1. organic synthesisOrganic synthesis is using electrode transfer electronsOrganic oxidation or reductionInstead of using chemicals direct oxidation or reduction organic matterIt is organic chemistry and electrochemistry and cross subject of chemical reaction engineeringOrganic synthesis ha

22、s mild reaction condition (can) under the atmospheric pressure, simple process and easy to realize automatic control, high selectivity, less by-product and less pollution, and even no pollution, etcAre one of the necessary ways of green synthesisKnown as the green industryBased on the advantages of

23、organic synthesis and the present situation of the traditional chemical synthesis of the three wastes pollutionOrganic electrosynthesis has achieved rapid developmentElectricity produced by the method of synthetic organic has more than 100 kinds of productsOrganic synthesis products production in th

24、e world from the past few tons to 100000 tonsOrganic synthesis important chemical raw materials adiponitrile production was already well knownWith Ce4 + / Ce3 + and Mn3 +, Mn2 + for REDOX medium indirect electrooxidation synthesis fluoro benzaldehydeThe mother liquor can be recycledThe whole process

25、 basic no pollutantsAgain, such asCan adopt the method of cathodic indirect electrooxidation in various oxidation medium for indirect epoxidation acid; With electrolytic synthesis of important biochemical reagents in pairs L - sulpho alanine and epoxy compound, 12. - diol compounds, adjacent halogen

26、ated alcohol, and other important organic compoundsOrganic synthesis technology is applied widelyThere are wide development prospects2.1.1. electrochemical water disinfectionIndustrial wastewater, sewage and swimming pool water, drinking water and water processing and preparation involves disinfecti

27、on technologyCommon disinfection technologies mainly include chlorine disinfection, ozone disinfection and ultraviolet radiation disinfectionChlorine is a high-quality disinfectantHave very strong sterilization algaAnd the price is lowApplication more widelyBut chlorine disinfection technology has a

28、 lot of shortcomingsNot only has a high risk of chlorine disinfection processAnd will produce a lot of toxic by-productsFor example, chloroform, carbon tetrachloride, etc many carcinogensFor people and environment has great harm; Ozone disinfection and ultraviolet radiation sterilization effect is g

29、oodBut its energy consumption and high pricesOnline electricity chemistry method preparation of disinfectant water disinfection technology has gained developmentElectrochemical water disinfection can make up for the inadequacy of the above methodsIt cheap energy saving, no residue, safetyFor example

30、, in the general conditionsOnline in electrolytic preparation of H2O2Have a good disinfection effectElectrochemical water disinfection can use graphite or graphite fiber electrode, titanium electrode, porous carbon and SnO2 electrode, etcCan also be based on electric adsorption and direct anodic oxi

31、dation auxiliary enzyme in cells of A electrochemical disinfection method2.1.2. other electrochemical processMembrane electrochemical technology such as electrodialysis, electric auxiliary to ion (auxiliary electrodialysis ion exchange) and electric flotation and electrocoagulationThrough alternativ

32、e serious damage to the environment of the old processWith its clean production processIn the aspect of environmental pollution protection, environmental pollution (see section 21113) plays an important roleFor example,By electrodialysis method can be highly purified water preparation and applicatio

33、n of desalination; Electric flotation and electric coagulation pretreatment can be used in all kinds of waterTechnology developing rapidly in recent electric to ionsIs combining electrodialysis and ion exchange technology and composition of a kind of new technologyIt with the reverse osmosis unit jo

34、int has been applied in preparation of feed water factoryElectricity to ion technology not only has the very high cost performanceAnd the need for acid, alkali regeneration chemical agentReducing waste liquid treatment and emissionsAccording to the expectedIn the next few years about 85% of industri

35、al water treatment system for RO/EDI technology3. electrochemical technology and environmental pollution3.1. liquid pollution treatment3.1.1. inorganic pollution of waste liquid treatmentUsing electrodeposition, electrochemical REDOX, photoelectrochemical oxidation and electrochemical methodCan hand

36、le a variety of inorganic waste liquid pollutionSuch as: toxic heavy metal ions and toxic inorganic salt (including cyanide and thiocyanate), sulfate, sulfide, ammonia, etcElectrochemical treatment of dilute waste liquid containing toxic heavy metal ions is one of the most commonly usedElectroplatin

37、g, metallurgy, printing circuit, developing many industrial emissions from a large amount of dilute waste liquid containing metal ionsIn recent years in the discharge of liquid metal ion content is more and more strictTraditional method of precipitation alkaline metal ion can only make Cu, zinc and

38、other minority in meeting the requirements of the emission concentration of metal ionsAnd has great pollution to the environmentThis prompted the electrochemical methods developed dilute liquid waste processing metal ionsElectrochemical methods dilute liquid waste processing metal ions depends on th

39、e removal efficiency of the particles mass transfer rate, the effective area of electrode, the occurrence of adverse eventsAnd the structure and material of the electrode is affecting mass transfer rate and the effective area of the main factors of electrodesoThe electrochemical method for treatment

40、 of waste liquid containing metal process core technology and the research direction is a new type of electrode structure, material of electrolytic cell design and developmentThe form of the electrolytic cell can be divided into: two-dimensional electrodes electrolytic cell and three-dimensional ele

41、ctrode electrolytic cellAccording to different pollutants and different production conditionsDifferent structures of cell has been applied in industrial pollution controlSee table 3Two-dimensional electrodes applied the most were flat plate electrode and electrode a rotating cylinderFlat plate elect

42、rode cell wide range of applicationsIts structure is simpleThe electric potential and current density distribution uniformEasy to regularly take out from the open cathode electrodeposition of metal pollutantsAfter removal of sediment electrode can be usedThe disadvantage of flat plate electrode cell

43、 is do not apply to the handling of dilute solutionThe rotating cylinder electrode cell with uniform potential and current density; Solution in slot turbulent flowTherefore has a high rate of mass transfer; Yin and Yang are two electrode distance interval is smallTherefore, trough small occupation s

44、paceOhmic losses small; Can achieve continuous productionElectrodes electrolytic cell is mainly used in a rotating cylinder of Fe, Cu, Ag, Cr, Ni and other metal ions removal or recoveryCompared with flat plate electrode cellRotating cylinder electrode cell energy consumption is higherThe three dime

45、nsional electrode cell electrode has a larger surface areaHigh mass transfer rateElectrode material of cheapUnder the condition of low potential productionCommon have packed bed electrode and fluidized bed electrodeFor three dimensional porous electrode cell research focus is to develop new electrod

46、e materials and the direction of new filling materialbutFor the momentThree-dimensional electrode cell there are a lot of technical difficultiesSo is not very widely usedIn industrial practiceTwo-dimensional electrode is superior to the effect of three dimensional electrodeEspecially the electrode i

47、s applied to a rotating cylinder to dilute liquid waste processing metal ions the best resultsMore, update the design of the electrode and electrolytic cell, development will make electrochemical methods to deal with waste liquid used more widely3.1.2. organic pollution of waste liquid treatmentUsin

48、g electrochemical methodOrganic pollutants can make direct electrochemical reaction on the electrodeInto a harmless substanceSuch as phenols, dealing with nitrogen organic dyes, cyanide, etc; Or indirect electrochemical reactionUsing the electrode reaction is strong oxidation in the middle of the ma

49、terialOxidation of organic pollutantsThe final degradationElectrochemical method for treatment of organic waste liquid pollution process and the electrode material, electrode surface structure and load condition, composition and concentration of electrolyte solution and other related factorsThe elec

50、trode material is the most important factorDifferent special catalytic electrode materials with different featuresCan produce different reaction or among different oxide materialTherefore the development of electrode materials is the key to the electrochemical method processing waste liquid organic

51、pollution technologyTable 4 presented some of the applications of electrochemical method for treatment of organic pollution liquid3.1.3. other electrochemical processElectrodialysis, ion exchange, electrodialysis and electric flotation and electrocoagulation not only can be used as a cleaner product

52、ion process in order to prevent environmental pollution (see section 11213)And they are also effective liquid dye processing methodIndustry with the method of electrodialysis treatment containing Ni2 +, CrO2-4, Sn2 +, phosphite and hypophosphite dilute solutionAuxiliary electrodialysis ion exchange

53、for its diversified designWide range of application, etcIs becoming a hot spot application developmentFor example from NiSO4 recycling Ni in dilute solutionEnrichment CuCl2 dilute solution, etcThe electric flotation and electrocoagulation can remove poison Cr6, are in the waste water +, phosphate, c

54、olloid, suspended solids and organic matter3.2. gas pollution treatmentChemical plants, thermal power plants and other industrial emissions from many toxic gas, pollution environmentSuch as: Cl2, H2S, SO2, NOx and CO2, etcElectrochemical methods can handle purifying exhaust gasFirst of all gaseous p

55、ollutants through the electrolyte by adsorption or absorptionAnd then directly on the electrode electrochemical pollutant conversionOr indirect use of homogeneous and heterogeneous REDOX medium of pollutantsElectrochemical method to purify waste gas process can be divided into the slot and tank proc

56、essGroove process gas is directly transfer to the electrochemical reactor and is processed via the adsorption; Trough craft is gas by adsorption to the independent first containerThen transferred to the electrochemical reactor for processingAs shown in figure 1Three electrochemical technology and en

57、vironmental monitoringIn electrochemical analysis method for the principle of electrochemical sensorsHas a rapid, sensitive, accurate, and the advantages of simple structure, easy to automationWidely used in environmental monitoring3.1 ion sensorsIon sensors can also be called ion selective electrod

58、eThe main part of the construction is ion selective membraneBecause the membrane potential changes with by measuring the concentration of ionsSo on the determination of ion selective membrane potential can be measured ion concentrationAccording to the type of membraneIon sensor has a solid membrane ion sensor: glass membrane, the undissolved salt and liquid membrane ion sensorsThe earliest glass film sensorsThe