给排水专业英语Unit7.ppt

1、Specialized English for Water and Wastewater Engineering给排水专业英语给排水专业英语 主讲教师：李康主讲教师：李康Lesson 7 Chemical oxidation化学氧化7.1 Words and expressions ReviewFrictional resistance 摩擦阻力摩擦阻力反冲洗反冲洗 Backwashing Interception ,intsepn n.拦截，截留截，截留Electrokinetic i,lektrkainetik adj.动电学的学的，电动的的Terminate t:mineit v.终止，

2、停止，止，停止，结束束Hydraulics haidr:liks n.水力学水力学快快滤池池 Rapid filter Gravity filter 重力重力滤池池7.1 Words and expressions ReviewlFilter medium 过滤介介质，滤料料l无烟煤无烟煤 Anthracite l煤煤-砂砂滤床床 Coal-sand beds lDual media filter 双双层滤料料滤池池lCoarse media 粗粗滤料料lTurbidity breakthrough 浊度穿透度穿透lFilter cycle 过滤周期周期lFilter effluent 滤后水

3、，后水，滤池出水池出水lFilter influent 滤前水，前水，滤池池进水水57.2 New words and expressionsDisinfection Disinfection ChlorineChlorineInfluent flow Influent flow OzoneOzone OxidationOxidation ReductionReductionEnzyme Enzyme Catalyst Catalyst Sulfide Sulfide Benzene Benzene 消毒消毒氯氯入流入流臭氧臭氧氧化氧化酶酶催化剂催化剂硫化物硫化物苯苯还原还原6n7.2 New

4、 words and expressionsn nOxidant/Oxidizing agent Oxidant/Oxidizing agent 氧化剂氧化剂 n nReducer/Reducing agent Reducer/Reducing agent 还原剂还原剂n nOxidation potential Oxidation potential 氧化电势，氧化性氧化电势，氧化性 n nReduction potential Reduction potential 还原电势，还原性还原电势，还原性n nAdvanced oxidation process Advanced oxidati

5、on process 高级氧化工艺高级氧化工艺(AOP)(AOP)n nHydrogen peroxide Hydrogen peroxide 过氧化氢过氧化氢n nAmmonia Ammonia 氨氨n nNonbiodegradable Nonbiodegradable 不能生物降解的不能生物降解的 n nOxidation-reduction reaction Oxidation-reduction reaction 氧化还原反应氧化还原反应7.3 Important sentences1.(第一段)Included in the following discussion is an i

6、ntroduction of the fundamental concepts involved in chemical oxidation,an overview of the uses of chemical oxidation in wastewater treatment,and a discussion of the use of chemical oxidation for the reduction of BOD and COD,the oxidation of ammonia,and oxidation of nonbiodegradable organic compounds

7、.nonbiodegradable organic compounds 难降解有机物有哪些？oxidation and reduction (第二段)The purpose of the following discussion is to introduce the basic concepts involved in chemical oxidation reactions.The topics to be discussed include(1)oxidation-reduction reactions,(2)half reaction potentials,(3)reaction po

8、tentials,(4)equilibrium constants for redox equations for redox equations,and(5)rate of oxidation-reduction reactions.redox 氧化还原作用？基本概念基本概念氨氨概述概述平衡常数平衡常数7.3 Important sentences1.(第三段)Oxidation-reduction reactions（5min）copper-Cu zinc-Zn Oxidation-reduction reactions Oxidation half reaction？Reduction

9、half reaction？equation equation-two-electron change-two-electron change7.3 Important sentences1.(第四段)Half-reaction potentials 2.Because of the almost infinite number of possible reactions,there are no summary tables of equilibrium constants for oxidation-reduction reactions.Of the many properties th

10、at can be used to characterize oxidation-reduction reactions,the electrical potential(i.e,voltage)or emf of the half reaction is used most commonly.Thus,every half reaction involving an oxidation or reduction has a standard potential E0 associated with it.3.（11-4）和（11-5）公式是否有错误？4.The half reaction p

11、otential is a measure of the tendency of a reaction to proceed to the right.Half reaction with large positive potential,E0,tend to proceed to the right as written.Conversely half reactions with large negative potential,E0,tend to proceed to the left.5.The relationship between electrical potential an

12、d reaction?无穷的，无限的无穷的，无限的electromotive force7.3 Important sentences1.(第五段)Reaction potentials2.The half-reaction potentials,discussed above,can be used to predict whether a reaction comprised of two half reactions will proceed as written.The tendency of a reaction to proceed is obtained by determini

13、ng the E0 reaction for the entire reaction as given by the following expression.3.The positive value for the E0 is taken as an indication that the reaction will proceed as written.The magnitude of the value,as will be illustrated subsequently,can be taken as a measure of the extent to which the reac

14、tion as written will proceed.减轻，缓和减轻，缓和7.3 Important sentences1.(第六段)Rate of oxidation-reduction reactions.2.As noted previously,the half-reaction potentials can be used to predict whether a reaction will proceed as written.Unfortunately,the reaction potential provides no information about the rate

15、at which the reaction will proceed.Chemical oxidation reactions often require the presence of one or more catalysts for the reaction to proceed or to increase the rate of reaction.Transition metal cations,enzymes,pH adjustment,and a variety of proprietary substances have been used as catalysts.Trans

16、ition metal 过渡金属？过渡金属？enzyme 酶酶 胃蛋白酶、胰酶、淀粉酶、消化酶胃蛋白酶、胰酶、淀粉酶、消化酶7.3 Important sentences1.(第七段)Applications 2.In the past,chemical oxidation was used most commonly to(1)reduce the concentration of residual organics,(2)control odors,(3)remove ammonia,and(4)reduce the bacterial and viral content of wastewater.Chemical oxidation is especially effective for the elimination of odorous compounds(e.g.,oxidation of sulfides and mercaptans).Now chemical oxidation is commonly used to(1)improve the treatabili