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氯化血红素脱铁的原理概述及解释说明1. 引言1.1 概述本文旨在深入探讨氯化血红素脱铁的原理，并对其进行全面的解释和说明。
氯化血红素脱铁是指将血红素中的铁离子去除，使其转变为无铁的代表性衍生物。
该过程具有广泛的应用领域和重要的科学意义，在生物医学领域、营养学研究等方面都具有重要价值。
1.2 文章结构本文分为五个主要部分，即引言、氯化血红素脱铁的原理、解释说明、结论及参考文献。
在引言部分，我们将概述文章内容、介绍文章结构，并阐明撰写此文的目的。
在接下来的部分中，我们将详细讨论氯化血红素脱铁的定义、背景以及其机制、实验方法和结果。
随后，我们将对氯化血红素脱铁进行理论解释，并探讨该过程在不同领域中的应用和重要性。
最后，我们将总结文章要点，探讨氯化血红素脱铁可能带来的意义与展望，并提出未来研究方向建议。
1.3 目的本文的目的是系统介绍和解释氯化血红素脱铁的原理。
通过深入研究其定义、背景、机制及实验方法等方面，我们将全面讨论该过程的理论解释，并明确其在不同领域中的应用领域和重要性。
同时，我们希望能够为未来研究提供参考，并为进一步探索氯化血红素脱铁的潜力与发展方向提供建议。
以上为“1. 引言”部分的内容撰写，请继续完成“2. 氯化血红素脱铁的原理”部分。
2. 氯化血红素脱铁的原理2.1 定义和背景氯化血红素脱铁是指从氯化血红素分子中去除铁元素的过程。
氯化血红素是一种色泽鲜艳的天然光敏物质，广泛存在于植物、细菌等生物体中。
其结构中含有一个核心四聚环的呋喃卟啉结构，而每个卟啉单元都与一个铁原子相连。
去除氯化血红素中的铁原子可以改变其吸收光谱和光敏特性，对于科学研究和现实应用具有重要意义。
2.2 脱铁机制氯化血红素脱铁涉及多种机制，其中最为常见的包括酸碱促进法、还原法和配位置换法。
在酸碱促进法中，通过调节溶液的pH值来促使氯化血红素发生脱铁反应。
一般情况下，在强酸性条件下（pH<3），两个正电荷带电的羧基与邻近酮基之间会发生质子转移，形成了稳定的酮醇式结构。
1.TheIdeal-GasEquation理想气体状态方程2.Partial Pressures分压3.Real Gases:Deviation from IdealBehavior真实气体：对理想气体行为的偏离4.Thevande rWaals Equation范德华方程5.Systemand Surroundings系统与环境6.Stateand State Functions状态与状态函数7.Process过程8.Phase相9.The First Lawof Thermodynamics热力学第一定律10.Heatand Work热与功11.Endothermicand Exothermic Processes吸热与发热过程12.Enthalpiesof Reactions反应热13.Hess’s Law盖斯定律14.Enthalpiesof Formation生成焓15.Reaction Rates反应速率16.Reaction Order反应级数17.Rate Constants速率常数18.Activation Energy活化能19.The Arrhenius Equation阿累尼乌斯方程20.Reaction Mechanisms反应机理21.Homogeneous Catalysis均相催化剂22.Heterogeneous Catalysis非均相催化剂23.Enzymes酶24.The Equilibrium Constant平衡常数25.the Directionof Reaction反应方向26.L eChatelier’s Principle列·沙特列原理27.Effects of V olume,Pressure,Temperature Changesand Catalystsi.体积，压力，温度变化以及催化剂的影响28.Spontaneous Processes自发过程29.Entropy (StandardEntropy)熵（标准熵）30.The Second Law of Thermodynamics热力学第二定律31.EntropyChanges熵变32.StandardFree-EnergyChanges标准自由能变33.Acid-Bases酸碱34.The Dissociation of Water水离解35.The Protonin Water水合质子36.Thep H ScalespH值37.Bronsted-Lowry Acidsand Bases Bronsted-Lowry酸和碱38.Proton-Transfer Reactions质子转移反应39.Conjugate Acid-Base Pairs共轭酸碱对71.ThePauli Exclusion Principle泡林不相容原理72.Electron Configurations电子构型73.The PeriodicTable周期表74.Row行75.Group族76.Isotopes,Atomic Numbers,andMass Numbers同位素，原子数，质量数77.Periodic Properties o fthe Elements元素的周期律78.Radiu of Atoms原子半径79.Ionization Energy电离能80.Electronegativity电负性81.Effective Nuclear Charge有效核电荷82.Electron Affinities亲电性83.Metals金属84.Nonmetals非金属85.Valence Bond Theory价键理论86.Covalence Bond共价键87.Orbital Overlap轨道重叠88.Multiple Bonds重键89.Hybrid Orbital杂化轨道90.The VSEPR Model价层电子对互斥理论91.Molecular Geometries分子空间构型92.Molecular Orbital分子轨道93.Diatomic Molecules双原子分子94.Bond Length键长95.Bond Order键级96.Bond Angles键角97.Bond Enthalpies键能98.Bond Polarity键矩99.Dipole Moments偶极矩100.Polarity Molecules极性分子101.Polyatomic Molecules多原子分子102.Crystal Structure晶体结构130.Peroxidesand Superoxides过氧化物和超氧化物131.Hydroxides氢氧化物132.Salts盐133.p-BlockElementsp区元素134.Boron Group(Boron,Aluminium,Gallium,Indium,Thallium)硼族（硼，铝，镓，铟，铊）135.Borane硼烷136.Carbon Group(Carbon,Silicon,Germanium,Tin,Lead)碳族（碳，硅，锗，锡，铅）137.Graphite,Carbon Monoxide,Carbon Dioxide石墨，一氧化碳，二氧化碳138.CarbonicAcid,Carbonatesand Carbides碳酸，碳酸盐，碳化物139.Occurrenceand Preparation of Silicon硅的存在和制备140.Silicic Acid，Silicates硅酸，硅酸盐141.Nitrogen Group(Phosphorus,Arsenic,Antimony,andBismuth)氮族（磷，砷，锑，铋）142.Ammonia,NitricAcid,PhosphoricAcid氨，硝酸，磷酸143.Phosphorates,phosphorus Halides磷酸盐，卤化磷144.Oxygen Group(Oxygen,Sulfur,Selenium,andTellurium)氧族元素（氧，硫，硒，碲）145.Ozone,HydrogenPeroxide臭氧，过氧化氢146.Sulfides硫化物147.Halogens(Fluorine,Chlorine,Bromine,Iodine)卤素（氟，氯，溴，碘）148.Halides,Chloride卤化物，氯化物149.The Noble Gases稀有气体150.Noble-GasCompounds稀有气体化合物151.d-Blockelementsd区元素152.Transition Metals过渡金属153.Potassium Dichromate重铬酸钾154.Potassium Permanganate高锰酸钾155.Iron Copper ZincMercury铁，铜，锌，汞156.f-Block Elementsf区元素nthanides镧系元素158.Radioactivity放射性159.Nuclear Chemistry核化学160.Nuclear Fission核裂变161.Nuclea Fusion核聚变162.analyticalchemistry分析化学163.qualitativeanalysis定性分析186.deviation偏差187.precision精密度188.relativestandarddeviation相对标准偏差（RSD）189.coefficientvariation变异系数（CV）190.confidencelevel置信水平191.confidenceinterval置信区间192.significanttest显著性检验193.significantfigure有效数字194.standardsolution标准溶液195.titration滴定196.stoichiometricpoint化学计量点197.endpoint滴定终点198.titrationerror滴定误差199.primarystandard基准物质200.amountofsubstance物质的量201.standardization标定202.chemicalreaction化学反应203.concentration浓度204.chemicalequilibrium化学平衡205.titer滴定度206.generalequationforachemicalreaction化学反应的通式207.protontheoryofacid-base酸碱质子理论208.acid-basetitration酸碱滴定法209.dissociationconstant解离常数210.conjugateacid-basepair共轭酸碱对211.aceticacid乙酸212.hydroniumion水合氢离子213.electrolyte电解质214.ion-productconstantofwater水的离子积215.ionization电离216.protoncondition质子平衡217.zerolevel零水准218.buffersolution缓冲溶液219.methylorange甲基橙220.acid-baseindicator酸碱指示剂221.phenolphthalein酚酞251.cerimetry铈量法252.redoxindicator氧化还原指示253.oxygenconsuming耗氧量（OC）254.chemicaloxygendemanded化学需氧量(COD) 255.dissolvedoxygen溶解氧(DO)256.precipitation沉淀反应257.argentimetry银量法258.heterogeneousequilibriumofions多相离子平衡259.aging陈化260.postprecipitation继沉淀261.coprecipitation共沉淀262.ignition灼烧263.fitration过滤264.decantation倾泻法265.chemicalfactor化学因数266.spectrophotometry分光光度法267.colorimetry比色分析268.transmittance透光率269.absorptivity吸光率270.calibrationcurve校正曲线271.standardcurve标准曲线272.monochromator单色器273.source光源274.wavelengthdispersion色散275.absorptioncell吸收池276.detector检测系统277.bathochromicshift红移278.Molarabsorptivity摩尔吸光系数279.hypochromicshift紫移280.acetylene乙炔281.ethylene乙烯282.acetylatingagent乙酰化剂283.aceticacid乙酸284.adiethylether乙醚285.ethylalcohol乙醇286.acetaldehtde乙醛287.β-dicarbontlcompoundβ–二羰基化合物288.bimolecularelimination双分子消除反应289.bimolecularnucleophilicsubstitution双分子亲核取代反应322.Michaelreacton麦克尔反应323.halogenatedhydrocarbon卤代烃324.haloformreaction卤仿反应325.systematicnomenclatur系统命名法e326.Newmanprojection纽曼投影式327.aromaticcompound芳香族化合物328.aromaticcharacter芳香性r329.Claisencondensationreaction克莱森酯缩合反应330.Claisenrearrangement克莱森重排331.Diels-Alderreation狄尔斯-阿尔得反应332.Clemmensenreduction克莱门森还原333.Cannizzaroreaction坎尼扎罗反应334.positionalisomers位置异构体335.unimoleculareliminationreaction单分子消除反应336.unimolecularnucleophilicsubstitution单分子亲核取代反应337.benzene苯338.functionalgrou官能团p339.configuration构型340.conformation构象341.confomationalisome构象异构体342.electrophilicaddition亲电加成343.electrophilicreagent亲电试剂344.nucleophilicaddition亲核加成345.nucleophilicreagent亲核试剂346.nucleophilicsubstitutionreaction亲核取代反应347.activeintermediate活性中间体348.Saytzeffrule查依采夫规则349.cis-transisomerism顺反异构350.inductiveeffect诱导效应t351.Fehling’sreagent费林试剂352.phasetransfercatalysis相转移催化作用353.aliphaticcompound脂肪族化合物354.eliminationreaction消除反应355.Grignardreagent格利雅试剂灭滴灵Metronidazole柠檬酸CitricAcid硝酸钙calciumnitrate癸二酸SebacicAcid冰醋酸glacialaceticacid维生素C磷酸镁MagnesiumAscorbylPhosphate 对苯二酚Hydroquinone环丙沙星盐酸CIPROFLOXACINHCL氢氧化钠SodiumHydroxide吗菌灵醋酸盐dodemorphacetate烯酰吗啉dimethomorph百菌清Chlorothalonil尼索朗hexythiazox哒螨灵pyridaben葡萄糖酸-δ-内酯gluconodeltalactone硫酸粘杆菌素colistinesulfate恩诺沙星EnrofloxacinBase土霉素盐酸OxyTetraCyclineHCl黄磷YellowPhosphorus索布瑞醇Sobrerol焦棓酸PYROGALLOL硫乙醇酸THIOGLYCOLLICACID茴香硫醚THIOANISOLE1-溴-3-氯丙烷1-BROMO-3-CHLOROPROPANE 氟苯FLUOROBENZEN叔丁基胺tert-butylamine丙烯酸树脂Acrylicresin维生素B6VITAMINB6磺胺胍Sulfaguanidine松香树脂GumRosin苯甲酸钠SODIUMBENZOATE双氧水HydrogenPeroxide6-氨基己烷-1-醇6-aminohexan-1-ol邻苯二甲酸酐PhthalicAnhydride2,3-二氨基甲苯2,3-diaminotoluene吲哚indole2-甲基吲哚2-methylindole三苯基硼triphenylborane松油精Dipentine十六烷醇CetylAlcohol呋喃-2-硼酸FURAN-2-BORONICACID莫匹罗星Mupirocin高锰酸钾PotassiumPermanganate噻苯咪唑Thiabendazole42-amino-2-(hydroxymethyl)-1,3,propanediol二环戊二烯Dicyclopentadiene(DCPD)金红石型氧化钛TitaniumDioxide(Rutile)Topgrade硼酸boricacid氧化铅LeadOxide邻苯二甲酸酐PhthalicAnhydride叔丁基锡烷tributylstannane碳黑CarbonBlackElftex430碳黑CarbonBlackN300碳黑CarbonBlackN-326磷酸PHOSPHORICACID硝酸铅LEADNITRATE硬脂酸铅LEADSTEARA TE次硫酸钠SodiumHydrosulfite磷酸二氢铵AmmoniumDihydrogenPhosphate 水合肼HydrazineHydrate6三聚磷酸钠SodiumTripolyphosphate氧化铁黄ironoxideyellow氧化铁红ironoxidered1,1,1-三氯乙烷1,1,1-TrichloroEthane氯化铵AmmoniumChloride苯酚PHENOL甲氧苄氨嘧啶TRIMETHOPRIM磷酸三钙tricalciumphosphate酒石酸苯甲曲秦PhendimetrazineTartrate碳酸氢钠sodiumbicarbonate氯四环素盐酸ChlortetracyclineHCl三水合氨卡青霉素AmpicillinTrihydratemicronized 山梨糖醇SorbitolPowder一水葡萄糖DextroseMonohydrate碳化钙calciumcarbide柚皮甙Naringin叶绿素铜钠盐sodiumcopper苏打灰sodaash酒石酸盐tartrate鉻酸銨AMMONIUMCHROMATE苦味酸PICRICACID甲酸铵AMMONIUMFORMATE7聚丙烯薄膜PPSHEETFOROPPTAPE氨基乙酸Glycine氨比西林AMPICILINE土霉素盐酸OxytetracyclineHCL6-溴-2-羟基萘6-Bromo-2-hydroxynaphthalene2，6-二甲氧基萘2,6-Dimethoxynaphthalene2，6-二羟基萘2,6-Dihydroxynaphthalene6-甲氧基-2-羟基萘6-Methoxy-2-hydroxynaphthalene 2-叔丁基-4-甲基苯酚2-Tertiary-butyl-4-methylphenol 炉甘石Calamine5-溴-2-甲基嘧啶5-Bromo-2-methylpyridine氯化镁MagnesiumChloride。
化学常用英语词汇1 ．The Ideal-Gas Equation 理想气体状态方程2. Partial Pressures 分压3. Real Gases: Deviation from Ideal Behavior 真实气体：对理想气体行为的偏离4. The van der Waals Equation 范德华方程5. System and Surroundings 系统与环境6. State and State Functions 状态与状态函数7. Process 过程8. Phase 相9. The First Law of Thermodynamics 热力学第一定律10. Heat and Work 热与功11. Endothermic and Exothermic Processes 吸热与发热过程12. Enthalpies of Reactions 反应热13. Hess’s Law 盖斯定律14. Enthalpies of Formation 生成焓15. Reaction Rates 反应速率16. Reaction Order 反应级数17. Rate Constants 速率常数18. Activation Energy 活化能19. The Arrhenius Equation 阿累尼乌斯方程20. Reaction Mechanisms 反应机理21. Homogeneous Catalysis 均相催化剂22. Heterogeneous Catalysis 非均相催化剂23. Enzymes 酶24. The Equilibrium Constant 平衡常数25. the Direction of Reaction 反应方向26. Le Chatelier’s Principle 列沙特列原理27.Effects ofVolume,Pressure,TemperatureChanges andCatalysts体积，压力，温度变化以及催化剂的影响28. Spontaneous Processes 自发过程29. Entropy (Standard Entropy) 熵（标准熵）30. The Second Law of Thermodynamics 热力学第二定律31. Entropy Changes 熵变32. Standard Free-Energy Changes 标准自由能变33. Acid-Bases 酸碱34. The Dissociation of Water 水离解35.TheProtoninWater水合质子36. The pH Scales pH 值37. Bronsted-Lowry Acids and Bases Bronsted-Lowry 酸和碱38.Proton-Transfer Reactions质子转移反应39. Conjugate Acid-Base Pairs 共轭酸碱对40. Relative Strength of Acids and Bases 酸碱的相对强度41. Lewis Acids and Bases 路易斯酸碱42. Hydrolysis of Metal Ions 金属离子的水解43. Buffer Solutions 缓冲溶液44. The Common-Ion Effects 同离子效应45. Buffer Capacity 缓冲容量46. Formation of Complex Ions 配离子的形成47. Solubility 溶解度48. The Solubility-Product Constant Ksp 溶度积常数49. Precipitation and separation of Ions 离子的沉淀与分离50. Selective Precipitation of Ions 离子的选择沉淀51. Oxidation-Reduction Reactions 氧化还原反应52. Oxidation Number 氧化数53. Balancing Oxidation-Reduction Equations 氧化还原反应方程的配平54.Half-Reaction半反应55. Galvani Cell 原电池56.Voltaic Cell伏特电池57. Cell EMF 电池电动势58.StandardE lectrode Potentials标准电极电势59. Oxidizing and Reducing Agents 氧化剂和还原剂60. The Nernst Equation 能斯特方程61. Electrolysis 电解62. The Wave Behavior of Electrons 电子的波动性63. Bohr’s Model of The Hydrogen Atom 氢原子的波尔模型64. Line Spectra 线光谱65. Quantum Numbers 量子数66. Electron Spin 电子自旋67. Atomic Orbital 原子轨道68. The s (p, d, f) Orbital s（ p ，d ，f）轨道69. Many-Electron Atoms 多电子原子70. Energies of Orbital 轨道能量71. The Pauli Exclusion Principle 泡林不相容原理72. Electron Configurations 电子构型73.ThePeriodicTable周期表74.Row行75. Group 族76. Isotopes, Atomic Numbers, and Mass Numbers 同位素，原子数，质量数77. Periodic Properties of the Elements 元素的周期律78. Radius of Atoms 原子半径79. Ionization Energy 电离能80. Electronegativity 电负性81. Effective Nuclear Charge 有效核电荷82. Electron Affinities 亲电性83. Metals 金属84. Nonmetals 非金属85. Valence Bond Theory 价键理论86. Covalence Bond 共价键87. Orbital Overlap 轨道重叠88. Multiple Bonds 重键89. Hybrid Orbital 杂化轨道90. The VSEPR Model 价层电子对互斥理论91. Molecular Geometries 分子空间构型92. Molecular Orbital 分子轨道93. Diatomic Molecules 双原子分子94. Bond Length 键长95. Bond Order 键级96. Bond Angles 键角97. Bond Enthalpies 键能98. Bond Polarity 键矩99. Dipole Moments 偶极矩100. Polarity Molecules 极性分子101. Polyatomic Molecules 多原子分子102. Crystal Structure 晶体结构103. Non-Crystal 非晶体104. Close Packing of Spheres 球密堆积105. Metallic Solids 金属晶体106. Metallic Bond 金属键107. Alloys 合金108. Ionic Solids 离子晶体109. Ion-Dipole Forces 离子偶极力110. Molecular Forces 分子间力111. Intermolecular Forces 分子间作用力112. Hydrogen Bonding 氢键113. Covalent-Network Solids 原子晶体114. Compounds 化合物115. The Nomenclature, Composition and Structure of Complexes 配合物的命名，组成和结构116.Charges,CoordinationNumbers,andGeometries电荷数、配位数、及几何构型117. Chelates 螯合物118. Isomerism 异构现象119. Structural Isomerism 结构异构120. Stereoisomerism 立体异构121. Magnetism 磁性122.E lectronConfigurations inOctahedral Complexes八面体构型配合物的电子分布123. Tetrahedral and Square-planar Complexes 四面体和平面四边形配合物124. General Characteristics 共性125. s-Block Elements s 区元素126. Alkali Metals 碱金属127. Alkaline Earth Metals 碱土金属128. Hydrides 氢化物129. Oxides 氧化物130.Peroxides andSuperoxides过氧化物和超氧化物131. Hydroxides 氢氧化物132. Salts 盐133. p-Block Elements p 区元素134.BoronGroup(Boron,Aluminium,Gallium,Indium,Thallium)硼族（硼，铝，镓，铟，铊）135. Borane 硼烷136. Carbon Group (Carbon, Silicon, Germanium, Tin, Lead) 碳族（碳，硅，锗，锡，铅）137. Graphite, Carbon Monoxide, Carbon Dioxide 石墨，一氧化碳，二氧化碳138. Carbonic Acid, Carbonates and Carbides 碳酸，碳酸盐，碳化物139. Occurrence and Preparation of Silicon 硅的存在和制备140. Silicic Acid ，Silicates 硅酸，硅酸盐141. Nitrogen Group (Phosphorus, Arsenic, Antimony, and Bismuth) 氮族（磷，砷，锑，铋）142. Ammonia, Nitric Acid, Phosphoric Acid 氨，硝酸，磷酸143. Phosphorates, phosphorus Halides 磷酸盐，卤化磷144.OxygenGroup(Oxygen,Sulfur,Selenium,andTellurium)氧族元素（氧，硫，硒，碲）145.Ozone,HydrogenPeroxide臭氧，过氧化氢146. Sulfides 硫化物147. Halogens (Fluorine, Chlorine, Bromine, Iodine) 卤素（氟，氯，溴，碘）148. Halides, Chloride 卤化物，氯化物149. The Noble Gases 稀有气体150. Noble-Gas Compounds 稀有气体化合物151. d-Block elements d 区元素152.TransitionMetals过渡金属153. Potassium Dichromate 重铬酸钾154.PotassiumPermanganate高锰酸钾155. Iron Copper Zinc Mercury 铁，铜，锌，汞156. f-Block Elements f 区元素157. Lanthanides 镧系元素158. Radioactivity 放射性159. Nuclear Chemistry 核化学160. Nuclear Fission 核裂变161. Nuclear Fusion 核聚变162. analytical chemistry 分析化学164. quantitative analysis 定量分析165. chemical analysis 化学分析167. titrimetry 滴定分析168. gravimetric analysis 重量分析法169. regent 试剂170. chromatographic analysis 色谱分析171. product 产物172. electrochemical analysis 电化学分析173. on-line analysis 在线分析174. macro analysis 常量分析175. characteristic 表征176. micro analysis 微量分析177. deformation analysis 形态分析178. semimicro analysis 半微量分析179. systematical error 系统误差180. routine analysis 常规分析181. random error 偶然误差182. arbitration analysis 仲裁分析183. gross error 过失误差184. normal distribution 正态分布185. accuracy 准确度186. deviation 偏差187. precision 精密度188. relative standard deviation 相对标准偏差（RSD ）189. coefficient variation 变异系数（CV ）190. confidence level 置信水平191. confidence interval 置信区间192. significant test 显著性检验193. significant figure 有效数字194. standard solution 标准溶液195. titration 滴定196. stoichiometric point 化学计量点197. end point 滴定终点198. titration error 滴定误差199. primary standard 基准物质200. amount of substance 物质的量201. standardization 标定202. chemical reaction 化学反应203. concentration 浓度204. chemical equilibrium 化学平衡205. titer 滴定度206. general equation for a chemical reaction 化学反应的通式207. proton theory of acid-base 酸碱质子理论208. acid-base titration 酸碱滴定法209. dissociation constant 解离常数210. conjugate acid-base pair 共轭酸碱对211. acetic acid 乙酸212. hydronium ion 水合氢离子213. electrolyte 电解质214. ion-product constant of water 水的离子积215. ionization 电离216. proton condition 质子平衡217. zero leve 零水准218. buffer solution 缓冲溶液219. methyl orange 甲基橙220. acid-base indicator 酸碱指示剂221. phenolphthalein 酚酞222. coordination compound 配位化合物223. center ion 中心离子224. cumulative stability constant 累积稳定常数225. alpha coefficient 酸效应系数226. overall stability constant 总稳定常数227. ligand 配位体228. ethylenediamine tetraacetic acid 乙二胺四乙酸229. side reaction coefficient 副反应系数230. coordination atom 配位原子231. coordination number 配位数232. lone pair electron 孤对电子233. chelate compound 螯合物234. metal indicator 金属指示剂235. chelating agent 螯合剂236. masking 掩蔽237. demasking 解蔽238. electron 电子239. catalysis 催化240. oxidation 氧化241. catalyst 催化剂242. reduction 还原243. catalytic reaction 催化反应244. reaction rate 反应速率245. electrode potential 电极电势246. activation energy 反应的活化能247. redox couple 氧化还原电对248. potassium permanganate 高锰酸钾249. iodimetry 碘量法250. potassium dichromate 重铬酸钾251. cerimetry 铈量法252. redox indicator 氧化还原指示253. oxygen consuming 耗氧量（OC ）254. chemical oxygen demanded 化学需氧量(COD) 255. dissolved oxygen 溶解氧(DO)256. precipitation 沉淀反应257. argentimetry 银量法258. heterogeneous equilibrium of ions 多相离子平衡259. aging 陈化260. postprecipitation 继沉淀261. coprecipitation 共沉淀262. ignition 灼烧263. fitration 过滤264. decantation 倾泻法265. chemical factor 化学因数266. spectrophotometry 分光光度法267. colorimetry 比色分析268. transmittance 透光率269. absorptivity 吸光率270. calibration curve 校正曲线271. standard curve 标准曲线272. monochromator 单色器273. source 光源274. wavelength dispersion 色散275. absorption cell 吸收池276. detector 检测系统277. bathochromic shif 红移278. Molar absorptivity 摩尔吸光系数279. hypochromic shift 紫移281. ethylene 乙烯282. acetylating agent 乙酰化剂284. adiethyl ether 乙醚285. ethyl alcohol 乙醇286. acetaldehtde 乙醛287. β-dicarbontl compound β–二羰基化合物288. bimolecular elimination 双分子消除反应289. bimolecular nucleophilic substitution 双分子亲核取代反应290. open chain compound 开链族化合物291. molecular orbital theory 分子轨道理论292. chiral molecule 手性分子293. tautomerism 互变异构现象294. reaction mechanism 反应历程295. chemical shift 化学位移296. Walden inversio 瓦尔登反转 n 297. Enantiomorph 对映体298. addition rea ction 加成反应299. dextro- 右旋300. levo- 左旋301. stereochemistry 立体化学302. stereo isomer 立体异构体303. Lucas reagent 卢卡斯试剂304. covalent bond 共价键305. conjugated diene 共轭二烯烃306. conjugated double bond 共轭双键307. conjugated system 共轭体系308. conjugated effect 共轭效应309. isomer 同分异构体310. isomerism 同分异构现象311. organic chemistry 有机化学312. hybridization 杂化313. hybrid orbital 杂化轨道314. heterocyclic compound 杂环化合物315. peroxide effect 过氧化物效应 t 316. valence bond theory 价键理论317. sequence rule 次序规则318. electron-attracting grou p 吸电子基319. Huckel rule 休克尔规则320. Hinsberg test 兴斯堡试验321. infrared spectrum 红外光谱。
The Effect of Temperature on ReactionRate温度对反应速率的影响反应速率是化学反应过程中一个非常重要的参数，它可以代表反应中物质的消耗或产生速度。
温度是影响反应速率的重要因素之一。
本文将阐述在理论和实验研究中温度对反应速率的影响。
理论基础热力学和动力学是研究反应速率的两个重要分支。
热力学研究反应是否可以进行，而动力学则探讨反应的速度和速率方程。
根据热力学原理，反应过程中需要扰动原有平衡热力学状态，因此需要吸收或释放热量来实现反应。
当温度上升时，反应物分子的速度增加，反应过程中的活化能减少，反应速率随之增加。
反应速率与温度变化的关系在温度改变下，反应速率会发生变化。
一个典型的实例是火柴点燃的过程。
火柴头燃烧的量少，在室温下需要大约10秒才能点燃。
然而，在高温下，点燃时间会大大缩短。
这是因为温度上升导致火柴头表面和空气之间的分子碰撞更加频繁，火柴头内部的分子更有可能高速振动，进而导致温度升高得更快，并促进反应的进行。
另一个典型实例是化学反应速率随温度变化的图示。
在一定温度范围内，反应速率随温度升高而增加，符合阿累尼乌斯方程式。
该方程式表达了当温度上升时，反应速率指数呈指数增加，反应速率随着温度的上升而指数级增加。
实验研究实验研究可以量化温度对反应速率的影响。
一般来说，在实验中，可以将反应物放在容器中，用加热器加热直至反应开始，测量反应物的消耗或产物的生成速率来确定反应速率。
研究表明，温度升高每10℃，反应速率大约增加2倍。
这种反应速率与温度的关系称为“阿累尼乌斯方程式”，其中n称为反应速率指数，Ea称为反应过程的活化能。
结论温度是影响化学反应速率最为重要的因素之一。
当温度升高时，反应过程中的活化能会减少，反应速率随之增加。
实验研究也表明，温度升高每10℃，反应速率大约增加2倍。
理解反应速率与温度变化的关系对于化学反应和工艺控制有着重要的意义，这种理解具有重要的工程和科学应用。
The Effect of Temperature on ProteinConformationProteins are essential components of living organisms and are responsible for carrying out various cellular functions. They are composed of long chains of amino acids that are folded into intricate 3-dimensional structures. The specific shape of a protein, or its conformation, plays a critical role in its function. Temperature is one of the key factors that can influence protein conformation. In this article, we will explore the effect of temperature on protein conformation and how it impacts their function.Temperature-induced protein denaturationProtein denaturation is a process in which the protein loses its native conformation and unfolds into a linear or random coil structure. This process can be triggered by several factors, including pH, salts, mechanical stress, and temperature. Among these, temperature is the most commonly studied factor that can induce protein denaturation.When proteins are exposed to high temperatures, the thermal energy causes the bonds that hold the protein structure together to break. Hydrogen bonds, which are weaker than covalent bonds, are the first to be broken. As the temperature continues to rise, the more significant covalent bonds that hold the protein together begin to break, further destabilizing the structure. Ultimately, the protein loses its native conformation, and its function is impaired.The effect of temperature on protein stabilityThe stability of a protein refers to its ability to maintain its native conformation in the face of various environmental conditions, including temperature. The stability of a protein is influenced by several factors, including the amino acid sequence, solvent conditions, and the presence of ligands or cofactors. Temperature can disrupt the stability of a protein by altering its structure and causing it to denature.Proteins have a range of thermal stability that depends on their amino acid sequence and their specific structure. Generally, proteins that are stable at higher temperatures have a higher content of hydrophobic amino acids, which can help to stabilize the structure through hydrophobic interactions. In contrast, proteins that are stable at lower temperatures tend to have more polar amino acids and a lower content of hydrophobic amino acids.The temperature at which a protein denatures is known as its melting temperature or Tm. The Tm of a protein is influenced by its intrinsic stability as well as the specific conditions under which it is studied. For example, the pH, salt concentration, and presence of other molecules can all affect the Tm of a protein.The effect of temperature on protein functionThe specific conformation of a protein plays a critical role in its function. Therefore, changes in protein conformation due to temperature can have a significant impact on their function. The effect of temperature on protein function can vary depending on the specific protein and the conditions under which it is studied.Some proteins are more sensitive to changes in temperature than others. For example, enzymes, which catalyze chemical reactions in the cell, have a specific optimal temperature range at which they function best. Outside of this range, the reaction rate can slow down or even stop altogether due to changes in protein conformation.Other proteins, such as transporters and receptors, are also sensitive to changes in temperature. Changes in protein conformation due to temperature can affect the ability of these proteins to bind to their ligands and carry out their function.ConclusionIn conclusion, temperature has a significant impact on protein conformation. High temperatures can cause proteins to denature, while changes in temperature can alter their stability and affect their function. Understanding the effect of temperature on protein conformation and function is essential for designing experiments and developing new drugs and therapies that target specific proteins.。
第32卷 第5期 2018年9月湖 南 工 业 大 学 学 报Journal of Hunan University of TechnologyV ol.32 No.5 Sep. 2018doi:10.3969/j.issn.1673-9833.2018.05.011收稿日期：2017-09-06基金项目：国家自然科学基金资助项目（51774127）作者简介：刘鹏程（1995-），男，湖南湘潭人，湖南工业大学硕士生，主要研究方向为资源回收利用， E-mail ：961571582@ 通信作者：肖 利（1973-），女，湖南湘潭人，湖南工业大学教授，博士，主要研究方向为二次资源循环利用，冶金物理化学， E-mail ：xiaoli_csu@预氧化-亚铁盐除砷工艺研究刘鹏程，肖 利，陈艺锋，田思雨（湖南工业大学 冶金与材料工程学院，湖南 株洲 412007）摘 要：采用预氧化-亚铁盐除砷法，对模拟含砷废水亚砷酸钠溶液进行了除砷研究。
以过氧化氢为氧化剂，将As(Ⅲ)氧化成As(Ⅴ)，加入氯化亚铁生成砷酸铁。
考察反应时间、溶液pH 值、反应温度、铁砷物质的量之比对砷酸铁生成的影响。
研究结果表明，当反应时间为2 h 、反应温度为85 ℃、溶液pH 值为4、铁砷物质的量之比为2.2时，氯化亚铁除砷效率最高，达99.85%。
X -ray 分析结果表明沉淀产物为砷酸铁，SEM 分析结果表明沉淀为直径5 μm 左右砷酸铁。
关键词：氯化亚铁；除砷；砷酸铁中图分类号：X781 文献标志码：A 文章编号：1673-9833(2018)05-0060-06Study on the Arsenic Removal Process by Pre-Oxidation Ferrous SaltLIU Pengcheng ，XIAO Li ，CHEN Yifeng ，TIAN Siyu（College of Metallurgy and Material Engineering ，Hunan University of Technology ，Zhuzhou Hunan 412007，China ）Abstract ：A research has been carried out on the arsenic removal from simulated arsenic containing wastewater by sodium arsenite solution with the pre-oxidation ferrous salt method adopted. Using hydrogen peroxide as its oxidant, an oxidization of As(Ⅲ) to As(Ⅴ) can be achieved, followed by the formation of iron arsenate with the addition of ferrous chloride. An investigation is to be conducted on the effects of reaction time, solution pH, reaction temperature and molar ratio of iron and arsenic on the formation of iron arsenate. The results show that the removal efficiency of arsenic by ferrous chloride reaches the highest point, i.e. 99.85%, with the reaction time being 2 h, the reaction temperature being 85 ℃, the pH value of the solution being 4, and the molar ratio of iron to arsenic being 2.2. An X -ray analysis shows that the precipitation product is to be iron arsenate, and SEM analysis shows that the precipitation is to be ferric arsenate slag with a diameter of about 5 micron.Keywords ：ferrous chloride ；arsenic removal ；iron arsenate1 研究背景砷是一种剧毒的类金属元素，是许多有色金属（铜、铅、锌等）的伴生元素。
Nano particle LiFePO 4prepared by solvothermal processLi Wang a ,Wenting Sun a ,Xianyi Tang b ,Xiankun Huang a ,Xiangming He a ,c ,*,Jianjun Li a ,Qingwu Zhang b ,Jian Gao a ,Guangyu Tian c ,Shoushan Fan daInstitute of Nuclear and New Energy Technology,Tsinghua University,Beijing 100084,PR China bChina University of Mining &Technology,Beijing 100083,PR China cState Key Laboratory of Automotive Safety and Energy,Tsinghua University,Beijing 100084,PR China dDepartment of Physics,Tsinghua-Foxconn Nanotechnology Research Center,Tsinghua University,Beijing 100084,PR Chinah i g h l i g h t sA glycol based solvothermal process is attempted to prepare nano LiFePO 4cathode materials. The sample delivers capacity retention of 100%after 100cycles at 100%depth of discharge. The sample presents an initial columbic ef ficiency of 98.9%and 100%during cycling afterward.The capacity of about 163mAh g À1at 0.1C-rate,157.8mAh g À1at 1C-rate,and 145.9mAh g À1at 5C-rate.a r t i c l e i n f oArticle history:Received 29September 2012Received in revised form 1March 2013Accepted 6March 2013Available online 26March 2013Keywords:Nano particleLithium iron phosphate Solvothermal GlycolHigh performancea b s t r a c tA glycol based solvothermal process combined with carbon coating is attempted to prepare nano particle LiFePO 4cathode materials for Li-ion batteries.Different concentration of starting materials,process time,pH values and process temperature are tried.Samples are characterized by XRD and SEM analysis.A carbon coating process with sucrose is used to make LiFePO 4/C composites.The optimized sample delivers capacity retention of 100%after 100cycles at 100%depth of discharge with initial columbic ef ficiency of 98.9%,cycling capacity of about 163mAh g À1at 0.1C-rate,159mAh g À1at 0.5C-rate,157.8mAh g À1at 1C-rate,and 145.9mAh g À1at 5C-rate,under the electrode formula of 80%LiFePO 4/C composites,10%carbon black and 10%binder.This study shows that proposed process can be a potential promising way to prepare high performance LiFePO 4cathode materials for lithium ion batteries.Ó2013Elsevier B.V.All rights reserved.1.IntroductionLithium-ion batteries power many portable devices and in the future are likely to play a signi ficant role in sustainable-energy systems for transportation and the electrical grid.According to the developing demands for Lithium-ion batteries,a good cathode material has to meet the following criteria:high capacity that can be retained for up to 1000cycles;stability that can withstand fast recharge and discharge and other possible extreme conditions;affordability for consumer electronics and large scale storage,andlow toxicity.Olivine LiFePO 4appears to meet many of these re-quirements when both its particle structure and surface chemistry are well tuned [1e 5].Though LiFePO 4suffers low electronic conductivity (w 10À9S cm À1)and slow lithium ion diffusion coef ficient (w 1.8Â10À14cm 2s À1),combination of carbon coating and size reduction have been proved to be an effective resolution [6,7].LiFePO 4nanoparticles are bene ficial to enhance electrochemical reaction [8e 11].Besides particle size,the crystal orientation and crystal plane,so resulting in particle morphology,are also sensitive factors for LiFePO 4of good performances [5,12,13].The commercial success of new cathode materials mainly de-pends on the preparation method.It is more for LiFePO 4material,according to the high requirements on morphology and structure control for high performances.Many preparation strategy,including solid state methods [14],sol e gel routes [15,16],and hydrothermal/*Corresponding author.Institute of Nuclear and New Energy Technology,Tsinghua University,Beijing 100084,PR China.Tel.:þ861089796073;fax:þ861089796031.E-mail addresses:hexm@ ,hexiangming@ (X.He).Contents lists available at SciVerse ScienceDirectJournal of Power Sourcesjournal ho mep age:www.elsevi /locate/jpowsour0378-7753/$e see front matter Ó2013Elsevier B.V.All rights reserved./10.1016/j.jpowsour.2013.03.101Journal of Power Sources 244(2013)94e 100solvothermal synthesis [11,17e 19],have been employed to develop nanocomposite C/LiFePO 4particles with controlled morphologies.However preparations involving solid-state reaction are energy intensive,poor in morphology control and batch stability.Fortu-nately,solution chemistry approaches,especially hydrothermal/solvothermal,are readily for crystalline structure tuning,high uni-formity in products and processing,as well as employing relatively low temperature,and is considered to be a commercially viable approach [20].However,assessing of solvothermal for industry is required.It is known that the formation of LiFePO 4during hydrothermal/sol-vothermal experiences a heterogenous nucleation,namely dissolving-crystallization process [21e 24],while nucleation,crystal growth and crystallization greatly depend on solvent,concentra-tion,temperature,time,pH value et al.[25,26]Nevertheless,oversensitive reactions may leads to too high process cost on controlling.In this sense,solvent is very important due to its multiple roles during solvothermal.In particular,ethylene glycol is preferable for solvothermal synthesis of LiFePO 4.Firstly,the high viscosity may slow down the ion diffusion rate,and thus prevent the particles from growing.Secondly,as (010)plane is reported to be the most readily access surface for Li þintercalation and is prominent in both calculated equilibrium and growth morphology,[27]ethylene glycol is helpful for (010)exposure due to its capping behavior on (010)plane and the low ion diffusion rate.In addition,ethylene glycol also plays an important role as a weak reducing agent to prevent the oxidation of Fe 2þto Fe 3þ,and this can ensure the purity of the product [28].Though its price is not very low,considering of the recycling strategy,ethylene glycol based sol-vothermal is still promising for industry.In this study,solvothermal is chosen as the synthetic method because of the feasibility of controlling the morphology and the accessibility of cheap raw materials,as well as relatively economic processing.To con firm the robustness of solvothermal process,effects of temperature,time,pH value,raw material ratio and concentration on LiFePO 4nano-particles are assessed carefully.Our results show that uniform LiFePO 4nanoparticles can be obtained in a wide temperature and time range.After a facile carbon-coating process,LiFePO 4/C composites conduct over 160mAh g À1at 0.1C rate.2.ExperimentalThe precursor for LiFePO 4is prepared by dissolving stoichio-metric amounts of LiOH $H 2O,FeSO 4$6H 2O and H 3PO 4(molar ratio 3:1:1)in glycol to form a solution (70mL,corresponding to 0.2mol L À1LiFePO 4),and then transferring the solution into a 100mL Te flon-lined stainless steel autoclave for solvothermal treatment.To assess the in fluences of solvothermal conditions on the morphology and size of the LiFePO 4particles,the solvothermal treatment are carried out at different temperatures or with different reaction times respectively.When the solvothermal reactions finish,the autoclave is cooled down naturally to room temperature and the reaction solution is washed by distilled water and dried at 80 C.To synthesize carbon-coated LiFePO 4powders,LiFePO 4,sucrose (C 12H 22O 11)and deionized water (H 2O)are mixed in a weight ratio of LiFePO 4:C 12H 22O 11:H 2O ¼20:1:2and milled for 4h in a mortar.The mixed slurry is dried and then sintered at 600 C for 1h in N 2.The carbon-coated LiFePO 4powders are finally obtained.The residual carbon content determined by thermogravimetry is about 2wt.%.Powder X-ray diffraction (XRD,D/max-rB)using Cu K a radiation is used to identify the crystalline phase.The sample morphology is observed by field emission scanning electron microscopy (SEM,JSM6301F).Experimental test cells for measurements use the cathode with the composition of 80wt.%LiFePO 4/C,10wt.%carbon black,and 10wt.%PTFE.The separator is a Celguard 2400microporous poly-propylene membrane.The electrolyte is 1M LiPF 6EC þDEC (1:1by volume).A lithium metal anode is used in this study.The cells are assembled in a glove box filled with argon gas.The charge e discharge cycling is galvanostatically performed at a current of 0.1e 5.0C with cut-off voltages of 2.75e 4.2V (versus Li/Li þ)at room temperature.Discharge rate capability after charging at C/10at upper cut-off voltage of 4.2V.C /n denotes the rate at which a full discharge takes n hours.The loading density of the electrode is 17mg cm À2.The voltage window is 2.5e 4.2V.3.Results and discussionProcessing temperature,duration,pH values,ratio of starting materials and concentration all greatly affect thedissolving-Fig.1.The LiFePO 4particles after glycol solvothermal reaction of 10h at temperature of 120e 240 C (a)XRD patterns;(b)SEM images.L.Wang et al./Journal of Power Sources 244(2013)94e 10095crystallization during solvothermal process,resulting in variety of products [20,21,26].However,the tolerance of products to tem-perature and time determines the reactor design and operation ually,increasing temperature can enhance the precipi-tation and grain growth of the solid crystal in a solvothermal pro-cess,but can also bring weak point,such as energy consumption and safety issue,from the viewpoint of industrial production.180 C is the most widely adopted temperature for hydrothermal/solvothermal synthesis of LiFePO 4particles on the basis of many reports [11,17],so temperatures ranging from 120 C to 240 C is chosen to evaluate the variation of crystal structure and morphology of LiFePO 4particles with temperature.Fig.1(a)and (b)shows the XRD patterns and SEM images of the LiFePO4particles obtained at various reaction temperatures at a fixed reaction time of 10h,respectively.It can be observed that crystalline LiFePO 4forms even at 120 C,indicating ethylene glycol can act as reductant even when temperature is only 120 C.Besides,all the XRD patterns are consistent with JCPDS (81-1173)standard olivine LiFePO 4patterns.This observation con firms that LiFePO 4samples can be prepared with high purity and considerably good crystallization in the whole temperature range,using ethylene glycol as reaction medium at different temperatures.Based on above analysis,the strong steady of olivine structure with temperature can be deduced,implying that an easy control on temperature field may be acceptable for the design of chemical caldron.All the LiFePO 4par-ticles are tiny cuboids,and their morphologies keep almost con-stant with temperature increasing,as shown in Fig.1b.Except that particles prepared at 240 C aggregate,the other samples prepared at lower temperatures are all well mono-dispersed.LiFePO 4sam-ples prepared at different temperature present similar size of about 60e 100nm long and 30e 50nm wide,indicative a little effect of temperature.This result again supports the steady of olivine LiFePO 4formation and crystallization to temperature.These results are quite different with related observations on hydrothermal,where both particle size and morphology generally present dramatic changes with temperature varying [21,23].The strong dependency of LiFePO 4nucleation and crystal growth on process temperature endow hydrothermal with flexibility toproduceFig.3.LiFePO 4particles prepared with different mole ratio of reactants,with [Fe 2þ]¼0.2M at 180 C for 10h (a)XRD patterns;(b)SEM and TEMimages.Fig.2.The LiFePO 4particles after glycol solvothermal reaction of different time at temperature of 180 C (a)XRD patterns;(b)SEM images.L.Wang et al./Journal of Power Sources 244(2013)94e 10096various LiFePO4particles,while it in turn brings high difficulty for process control.As mentioned before,180 C is the widely adopted temperature for LiFePO4preparation.Then the effect of process time on crys-tallization and morphology of LiFePO4is investigated with afixed synthesis temperature of180 C,as shown in Fig.2.Crystalline LiFePO4can form within0.5h without any impurities,which can be detected by XRD analysis.It can be observed that the crystallinity of LiFePO4particles enhances obviously after1.5h and keeps almost constant in longer time,according to the XRD patterns(Fig.2a). Then very strict control on time may be not quite necessary during processing in view of crystallinity.However,cases for morphology and particles size are different.With process time increasing,the morphology changes gradually,and the average particle size varies obviously.For example,LiFePO4particles prepared within1h present average particle size of100nm long and50nm wide,while become around150nm long and80nm wide when the process time is increased to4h,similar morphology,and become about 80nm long and30nm wide when the process time is longer than 8h.Fortunately,LiFePO4particles prepared with different times are all highly dispersive and shows a very narrow size distribution. Though process time dose show a slight effect on morphology and grain size of LiFePO4particles,the constancy of olivine LiFePO4 formation and crystallization to process time is still quite accept-able in view of application.For hydrothermal,morphology and grain size of LiFePO4particles also show less dependency on pro-cess time when compared with that on temperature.However,the changes in average particles size and size distribution are so dra-matic that a careful process control is considerably necessary for high quality products and high batch uniformity.The differences between solvothermal and hydrothermal may come from the difference in ion diffusion rate,that is low ion diffusion rate results in low crystal growth[28].Though the requirements on temperature control and time control of a reaction are of the most importance for design of a tank reactor,the ratio of raw material,concentration and pH value are also key factors determine the species,crystal phase,morphology and yield.As reported,the mole ratio of Li:Fe:P associates with electrochemical performances can be considered as a criterion for purity evaluation of LiFePO4product.Then the dependency of LiFePO4purity on mole ratio of the reactants is investigated,as shown in Fig.3and Table1.Here,only the portion of H3PO4is considered because it is reported to be associated strongly with particle size[18],yield[25]and Fe3þimpurities[21]in hydrother-mal.When the Li:Fe:P changes from3:1:0.8to3:1:1.2,the XRD patterns of the as-prepared LiFePO4particles are similar in both peak position(Fig.3a),indicative of the pure olivine LiFePO4ac-cording to JCPDS(81-1173).However,the corresponding SEM mi-crographs disclose significant changes in particle morphology and size distribution.As can be observed from Fig.3b,LiFePO4prepared with Li:Fe:P¼3:1:1.2is rectangle in shape,20e30nm thick,200e 300nm long and100e150nm wide.The TEM image confirms the high tidiness and high dispersity of these nano-flakes,and the most exposed surface seems to be(100)plane as determined by electron diffraction patterns.However,LiFePO4prepared with Li:Fe:P¼3:1:1 and Li:Fe:P¼3:1:0.8remain the short rod-like morphology,though the particles size of the latter is about twice larger than the former. The corresponding Li:Fe:P in thefinal LiFePO4product also varies greatly with different reactant ratio,as shown in Table1.LiFePO4 prepared with Li:Fe:P¼3:1:1.2shows the lowest phosphate con-tent(Li:Fe:P¼1.026:1:0.781),while Li content also changes less. According to these results,to approach the stoichiometric ratio,as well as high purity of crystal phase and preferable morphology,the reactants with Li:Fe:P ratio of3:1:1is suggested.Concentration generally plays significant role on particle size and morphology,while interestingly the dependency of species on concentration is observed in our study.As shown in Fig.4a,the precipitations prepared with Li:Fe:P¼3:1:1.2and Li:Fe:P¼3:1:1both show obvious impurities when[Fe2þ]is0.1M.The impurities appear when the dosageofFig.4.XRD patterns and corresponding SEM micrographs of solvothermal LiFePO4with different mole ratio of reactants,with[Fe2þ]¼0.1M at180 C for10h(a)XRD patterns;(b)SEM micrographs.Table1Atomic ratio of reactants and as-prepared LiFePO4.Samples A B CLi:Fe:P(mole)Li:Fe:P(mole)Li:Fe:P(mole)Reactants3:1:0.83:1:13:1:1.2As-prepared LiFePO4 1.155:1:0.953 1.113:1:0.999 1.026:1:0.781L.Wang et al./Journal of Power Sources244(2013)94e10097phosphoric acid increasing.However,these impurities cannot be distinguished by SEM.As shown in Fig.4b,the LiFePO 4particles prepared with Li:Fe:P ¼3:1:1and Li:Fe:P ¼3:1:0.8are all neat and well mono-dispersed.What is more,their morphology and particle size are very similar.This reminds us that though the electro-chemical performance are the most convinced criterion for LiFePO 4evaluation,a reasonable understanding among reaction condition and products is more essential for process control.Fig.5shows the XRD patterns and corresponding SEM images for the LiFePO 4particles prepared in solutions with different pH value.Except the sample prepared when the pH is 4,all the XRD re flections in all the other samples can be indexed on the basis of an orthorhombic olivine-type LiFePO 4structure without any detect-able impurity phases (Fig.5a).The changes in crystalline orienta-tion can be observed according to the relative peak density,and it can be con firmed further from Fig.5b.The LiFePO 4particles present totally different shape,size and aggregation,indicating a dramatic in fluence of pH value.A neutral solution is more preferred based on these results.High temperature and long duration are bene fit for crystalliza-tion.As shown in Fig.6,the unit cell volume of as-prepared LiFePO 4particle approaches to the standard (PDF-83-2092)gradually with temperature increasing,though the differences among the unit cell volumes for different temperatures are not very signi ficant.In particular,for the samples prepared at temperatures higher than180 C,their unit cell volumes are quite close and the differences are comparable with re finement error,this observation is similar to synchrotron X-ray diffraction investigation on in situ hydrothermal synthesis of LiFePO 4[29].In the cases of duration,the unit cell volume increases obviously with time accumulating,and slows down when the duration is longer than 480min,indicating that poor crystalline will be obtained when the time is less than paring with temperature and duration,pH shows more week in fluence on crystallinity.It seems from Fig.6c that neutral solution is desired to get LiFePO 4particles with high crystallinity.Fig.7a compares the charge e discharge pro files for the 1st,30th,60th and 100th cycle.After carbon coating,LiFePO 4particles,which prepared with Li:Fe:P ¼3:1:1at 180 C for 10h,exhibit a high initial discharge and discharge capacity of 161mAh g À1and 162respec-tively,which are close to the theoretical value of 170mAh g À1.The initial columbic ef ficiency is 99.4%and the difference between the charge and discharge curves is very little as seen in Fig.7a,indi-cating the high purity of the olivine LiFePO 4structure and adequate electronic conductivity.In the following cycles,it present little dif-ference of the charge/discharge curves during cycling,indicating that irreversible structure evolution or side reactions does not happen during cycling.Accordingly,this LiFePO 4sample exhibits excellent cycleability with no noticeable fade and very high columbic ef ficiency in 100cycles,as seen in Fig.7b.Coloumbic ef ficiency is near 100%,which plays very important role fortheFig.6.The unit cell volume as a function of preparation condition.The unit cell volume is determined from Rietveld re finement.Fig.5.The LiFePO 4particles after glycol solvothermal reaction of 12h at 180 C.The starting solutions are adjusted to be different pH values.(a)XRD patterns;(b)SEM images.L.Wang et al./Journal of Power Sources 244(2013)94e 10098cycling life of a practical battery [30].The rate capability of this LiFePO 4sample is evaluated with loading density of 17mg cm À2,as shown in Fig.7c.The reversible capacities delivered are 164mAh g À1,158mAh g À1and 147mAh g À1at 0.1C,1C and 5C,andthe discharge plateau is above 3V versus Li þ/Li,indicating good performance as reported elsewhere [31,32].The excellent capacity,cycleability and rate capability of the LiFePO 4sample prepared by solvothermal may be favored from both the nano-sized (80nm long and 30nm wide)and the good crystallinity [23,33,34].In this sense,ethylene glycol based solvothermal process may pave a promising way to prepare high performance nano LiFePO 4.4.ConclusionsLiFePO 4particles with average size of 80nm long and 30nm wide,highly pure olivine structure and high dispersity can be prepared by solvothermal with ethylene glycol as solvent without any reductant.What is more,the solvothermal conditions,including temperature and duration,show little effect on the crystal structure,particle size and morphology,indicating a good robustness for industry production.The proposed ethylene glycol based solvothermal process may pave a promising way to prepare high performance nano LiFePO 4.On the other hand,the ratio and concentration of reactant and the pH value of the process show signi ficant effect on the purity,crystal structure,particle size and morphology,which in turn endow a wide possibility for product tuning.In particular,LiFePO 4particles prepared by this sol-vothermal process exhibit a reversible capacity of 164mAh g À1,as well as high cycleability and good rate capability.So ethylene glycol based solvothermal process is a promising strategy for industry production of LiFePO 4with high performance.AcknowledgmentsThe authors highly appreciate the comments for the revision from the anonymous reviewers.This work is supported by the MOST (Grant No.2011CB935902,No.2010DFA72760,No.2011CB711202and No.2013CB934000),the NSFC (Grant No.20901046and No.20903061),the Tsinghua University Initiative Scienti fic Research Program (Grant No.2010THZ08116,No.2011THZ08139,No.2011THZ01004and No.2012THZ08129)and State Key Laboratory of Automotive Safety and Energy (Grant no.ZZ2012-011).The authors also highly appreciate the assistance of XRD analysis from Chaochao Huang.References[1]P.P.Prosini,M.Carewska,S.Scaccia,P.Wisniewski,S.Passerini,M.Pasquali,J.Electrochem.Soc.149(2002)A886e A890.[2]L.Wang,X.M.He,W.T.Sun,J.L.Wang,Y.D.Li,S.S.Fan,Nano 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温度对半导体影响的书英文回答：The effect of temperature on semiconductors is acrucial aspect to consider in the field of electronics. As temperature changes, it can have both positive and negative impacts on the performance and reliability of semiconductor devices.One of the main effects of temperature on semiconductors is the change in electrical conductivity. Generally, as temperature increases, the conductivity of a semiconductor also increases. This is due to the increased thermal energy, which allows more charge carriers to move freely within the material. As a result, the resistance of the semiconductor decreases, and it becomes more conductive.However, this positive effect of temperature on conductivity can also have negative consequences. For instance, if the temperature rises too high, it can lead tothermal runaway, where the increased conductivity causes excessive heating and further increases the temperature. This can ultimately result in the device failing or even burning out.Another important effect of temperature on semiconductors is the impact on bandgap energy. The bandgap energy is the energy difference between the valence band and the conduction band in a semiconductor. At higher temperatures, the bandgap energy decreases, which meansthat the semiconductor becomes more conductive and allows more charge carriers to move across the bandgap. This can affect the performance of devices such as diodes and transistors, as it can lead to increased leakage currents and reduced efficiency.Furthermore, temperature can also affect the mobility of charge carriers in semiconductors. Mobility refers to the ease with which charge carriers can move through the material. At higher temperatures, the mobility of both electrons and holes in a semiconductor generally increases. This can lead to improved device performance, as the chargecarriers can move more freely and quickly. However, at extremely high temperatures, the mobility can besignificantly reduced due to scattering effects, which can negatively impact device performance.In addition to these electrical effects, temperaturecan also affect the mechanical properties of semiconductors. For example, as the temperature changes, the coefficient of thermal expansion of the semiconductor material can cause stress and strain in the device. This can lead to mechanical failure or even cracking of the semiconductor.中文回答：温度对半导体的影响是电子领域中需要考虑的一个关键因素。
EFFECTS OF TEMPERATURE,pH,AND IRON/CLAY AND LIQUID/CLAY RATIOS ON EXPERIMENTAL CONVERSION OF DIOCTAHEDRAL SMECTITE TO BERTHIERINE,CHLORITE,VERMICULITE,OR SAPONITE R EGINE M OSSER-R UCK1,*,M ICHEL C ATHELINEAU1,D AMIEN G UILLAUME2,D ELPHINE C HARPENTIER3,D AVY R OUSSET1,O DILE B ARRES4,AND N ICOLAS M ICHAU51G2R,Nancy-Universite´,CNRS,CREGU,Boulevard des Aiguillettes,B.P.239,F-54506Vandoeuvre-le`s-Nancy,France 2LMTG,UMR5563CNRS-UPS-IRD,Observatoire Midi-Pyre´ne´es,14avenue Edouard Belin,31400Toulouse,F rance 3CNRS-Universite´de Franche-Comte´/UMR6249Chrono-environnement,16route de Gray,25065Besanc¸on,France4Laboratoire Environnement et Mine´ralurgie,CNRS UMR7569,15Avenue du Charmois,BP40,54501Vandoeuvre-le`s-Nancy,France5ANDRA,Direction Scientifique/Service Mate´riaux,Parc de la Croix Blanche,1/7rue Jean Monnet,92298Chaˆtenay-Malabry,FranceAbstract—In deep geological repositories for high-level nuclear wastes,interactions between steelcanisters and clay-rich materials may lead to mineralogical transformations with a loss of the confiningproperties of the clays.Experiments simulating the conversion of smectite to Fe-rich clay phases in contactwith Fe metal have been carried out to evaluate such a possibility by taking into account the effects of aseries of critical parameters,including temperature,pH,and Fe/clay(Fe/C)and liquid/clay(L/C)ratios.The mineralogical and chemical transformations observed in these experiments have been compared withdata from the literature,and subsequently used to propose a conceptual model for the main mineralogicaltransformations which can be expected in clay formations surrounding high-level nuclear wasterepositories.In the presence of Fe metal and under low oxygen fugacity(<10À40)the main mineralogicalsequences are as follows:(1)up to150ºC,under neutral pH,and L/C>5:dioctahedral smectite(di-sm)?7A˚Fe-rich phase(berthierine,odiniteÀcronstedtite)for large Fe/C ratios(>0.5),or di-sm?Fe-rich di-sm+Fe-richtrioctahedral smectite(tri-sm)for small Fe/C ratios(0.1);(2)up to150ºC,under alkaline pH(10À12),and L/C>5:di-sm?Fe di-sm(Ôpalygorskite)for a smallFe/C ratio(0.1);(3)at300ºC,Fe/C=0.1,and L/C>5:di-sm?Fe-rich saponite?trioctahedral chlorite+feldspar+zeolite(near-neutral pH);di-sm?Fe-rich vermiculite+mordenite(pH10À12).Low temperatures(<150ºC)and large L/C and Fe/C ratios seem to favor the crystallization of theserpentine group minerals instead of Fe-rich trioctahedral smectites or chlorites,the latter being favored byhigher temperatures.The role of L/C and Fe/C ratios and the competition between them at differenttemperatures is a crucial point in understanding the transformation of smectite in contact with Fe metal.Key Words—Berthierine,Chlorite,Fe Metal,Nuclear Waste,Saponite,Smectite,Vermiculite.INTRODUCTIONThe interaction between smectites and Fe metal has been investigated in recent years in response to queries by nuclear-waste management agencies about the long-term behavior of engineered barriers after closure of the repository.Previous works,dealing with Fe-clay inter-action,report the formation of distinct types of clays (serpentine-like phases,dioctahedral or trioctahedral Fe-rich smectites,chlorite)and distinct mineral sequences,and sometimes appear to be contradictory. The contradiction has encouraged this comparison of previous experimental conditions and results with new data.In close contact with the waste packages(‘near-field system’)and in reduced conditions,water is unstable,Fe is released,and H2is produced.The main parameters to be considered in such a system are shown in Figure1and a summary of the experimental conditions and experimental results described in the literature is presented in Table1.Experimental temperaturesDepending on countries and concepts,the initial temperature of the overpack in the repository will vary between80ºC and100ºC.The main problem which arises when conducting experiments on smectites at such temperatures is the difficulty in reaching equilibrium, especially when the L/C ratio is small.In engineered clay-barrier conditions,L/C is~0.2Ô0.1,and it depends on the density of the bentonite.To compensate for kinetic effects,one possibility is to increase the temperature by conducting the experiments at greater*E-mail address of corresponding author: regine.ruck@g2r.uhp-nancy.frDOI:10.1346/CCMN.2010.0580212Clays and Clay Minerals,Vol.58,No.2,280–291,2010.temperatures,up to 250À300ºC (Guillaume,2002;Guillaume et al.,2003,2004;Wilson et al.,2005,2006;Charpentier et al.,2006).Another possibility is to increase the reactive surface by increasing the dispersion of particles and the amount of water.Changes in redox conditions and Fe concentration in the fluidsAfter closure of the repository,the engineered barrier will be submitted to increasingly reducing conditions (1,2,and 3in Figure 1).The scenario includes (1)the consumption of residual oxygen introduced in the pores during the early steps through the oxidation of the Fe 2+phases such as pyrite;and (2)the production of H 2due to the instability of water in the presence of Fe metal (Garrels and Christ,1965).The Fe metal Àwater inter-action results in a drastic reduction in f O 2to the water instability boundary,e.g .within the field of magnetite +H 2,and close to the Fe metal +H 2field.At an f O 2fixed by the boundary Fe metal/magnetite or less than the f O 2determined by the equilibrium:H 2O ?H 2+ÝO 2the Fe metal is transformed into magnetite following the reaction:3Fe 0+2O 2?Fe 3O 4thus yielding the mass balance reaction:4H 2O +3Fe 0?Fe 3O 4+4H 2Changes in pH and in the ionic strengthThe penetration of alkaline fluids issued from the concrete-water interaction in other engineered parts ofthe repository must result in an increase in pH of the interstitial fluid within the clay barrier.Alkaline fluids are generally progressively neutralized by the interaction with clays,as shown by experiments (trend a in Figure 1).The pH decreases from values of 12or 10to ~8.5(at 80ºC for instance),when no alkaline reserve is introduced,e.g .when the alkalinity of the incoming fluid is only considered as a starting experimental feature and is not maintained (Charpentier et al.,2006).The dissolution of Fe metal may produce an increase in pH (trend b in Figure 1)if no other mineral reaction is involved:Fe 0+2H 2O ?H 2+2OH À+Fe 2+When an allochtonous source of fluids is considered,e.g.alkaline fluids from the concrete parts of the repository,the ionic strength of the incoming fluids in contact with the steel containers will increase.In such a case,the increasing activity of calcium stabilizes other kinds of minerals such as zeolites (Charpentier et al.,2006).The reported experiments (Table 1)were carried out in autoclaves in the presence of air,e.g.with an O 2reserve (Lantenois,2003;Lantenois et al.,2005;Perronnet,2004;Perronnet et al.,2008),under argon atmosphere (Guillaume et al.,2003,2004),or under N 2atmosphere (Wilson et al.,2005).Various amounts of Fe,as powders of metal (Fe 0)and/or oxides (Fe 2O 3,Fe 3O 4),were added to the experimental media leading to different Fe/C ratios,from 0.1to 2,according to the authors.Liquid/clay ratios also vary.Experiments were conducted at L/C values of 10(Guillaume et al.,2004;Charpentier et al.,2006),16.7(Perronnet,2004;Perronnet et al.,2008;Lantenois et al.,2005),andFigure 1.Main parameters taken into account in the experimental modeling of the Fe Àclay interactions:(a)pH reduction due to alkaline fluid Àbentonite interaction;(b)pH increase due to Fe dissolution;(c)temperature-pH field chosen for new data in this study:(1)excavation under atmospheric f O 2;(2)f O 2reduction while O 2stock lasts;and (3)instability of water.Vol.58,No.2,2010Effects of pH and Fe/C and L/C ratios on the transformation of smectite 281T a b l e 1.L i s t o f p u b l i s h e d r e s u l t s a s a f u n c t i o n o f d i f f e r e n t p h y s i c a l c h e m i c a l e x p e r i m e n t a l p a r a m e t e r s .—————————————————————————E x p e r i m e n t —————————————————————————M a i n n e w l y -M i x t u r e L i q u i d /c l a y m a s s r a t i o (L /C )I r o n /c l a y m a s s r a t i o (I /C )S t a r t i n g r e d o x c o n d i t i o n s S t a r t i n g p H o f e x p e r i m e n t a l s o l u t i o n sT i m e T e m p e r a t u r e f o r m e d c l a y p h a s e s B y -p r o d u c t sA u t h o r sM X 80+F e +m a g n e t i t e10(N a ,C a )-C l 0.1A r g o n a t m o s p h e r e F e /m a g n e t i t e (À550m V m e a s u r e d )~71À12m o n t h s80ºC a n d150ºC F e -r i c h d i -s mN o t d e t e r m i n e dG u i l l a u m e (2002),G u i l l a u m e e t a l .(2004)300ºCF e -r i c h t r i -s m (s a p o n i t e l i k e )+F e 2+-c h l o r i t eQ u a r t z ,f e l d s p a r ,z e o l i t e (e r i o n i t e l i k e )G u i l l a u m e e t a l .(2003)M X 80+F e +m a g n e t i t e 10(a l k a l i n e s o l u t i o n :N a C l +C a (O H )2)0.1A r g o n a t m o s p h e r e F e /m a g n e t i t e 12.31À9m o n t h s80ºC a n d 150ºCd i -s me c t i t eT r a n s i t o r y p a l y g o r s k i t eC h a r p e n t i e r e t a l .(2006)300ºCF e 2+-r i c h v e r m i c u l i t eM o r d e n i t eC h a r p e n t i e r e t a l .(2006)M o n t m o r i l l o n i t e (S W y 2)/B e i d e l l i t e (S B l d -1)/N o n t r o n i t e (G a r f i e l d )+F e (N o d e s t a b i l i z a t i o n o f t r i o c t a h e d r a l s m e c t i t e s )16.7(p u r e w a t e r o r s p r i n g w a t e r )1t o 2A t m o s p h e r i c o r a r g o n a t m o s p h e r e 7t o 1145d a y s 80ºC7A˚p h a s e s (g e l s ):O d i n i t e –c r o n s t e d t i t e s e r i e sM a g n e t i t e L a n t e n o i s e t a l .(2005)F o C a 7o r C a -s m e c t i t e (P r a s s a )o r C a -n o n t r o n i t e +F e16.7(E v i a n )o r N a C l 15m m o l L À10.13t o 0.33A t m o s p h e r i c7.21À12m o n t h s80ºC7A˚p h a s e s :b e r t h i e r i n e ,o d i n i t e ,c r o n s t e d t i t e (F e /C =0.13À0.3a n d t i m e =1À3m o n t h s )M a g n e t i t eP e r r o n n e t (2004)P e r r o n n e t e t a l .(2008)T o u r n e m i r e +F e N o t o b s e r v e d M X 80+F e 3m o n t h sN o t o b s e r v e d P u r i f i e d M X 80+F e7A˚p h a s e s N a -m o n t m o r i l l o n i t e +m a g n e t i t e +F e +c a l c i t e 66.7(N a C l s o l u t i o n )0.57;0.68;0.78<h e m a t i t e -m a g n e t i t e N 2a t m o s p h e r e 9.73t o 4.1593,114d a y s250ºCF e 2+r i c h s m e c t i t e (s a p o n i t e -l i k e )M a g n e t i t eW i l s o n e t a l .(2005,2006)N a -m o n t m o r i l l o n i t e +F e66.7(F e C l 2)~0.6>h e m a t i t e -m a g n e t i t e4.24t o 4.7190,92d a y s80ºC ,150ºC ,250ºC7A˚p h a s e s (b e r t h i e r i n e o n l y a t 250ºC )66.7(Wilson et al.,2005,2006).Experiments carried out at high temperature to compensate for kinetic effects yielded to the formation of Fe-saponite and chlorite after dioctahedral Na-Ca smectite at300ºC(Guillaume et al., 2003)or berthierine-like minerals at250ºC(Wilson et al.,2005,2006).At lower temperatures(<150ºC), dioctahedral smectite was sometimes preserved (Guillaume,2002;Guillaume et al.,2004;Charpentier et al.,2006).On the other hand,Lantenois et al.(2005), Perronnet(2004),and Perronnet et al.(2008)reported the formation of a7A˚phase(berthierine or a mineral of the odiniteÀcronstedtiteÀgreenalite series)for experi-ments carried out at80ºC.An overall consideration of the experimental conditions and experimental results compiled from the available data of the literature (Table1)shows that the mineralogical assemblages obtained after experiment are probably very dependent on parameters such as the Fe/C and the L/C ratios.The purpose of the present study was to evaluate the role of these parameters by comparing published data(Table1) to results obtained from a new set of experiments carried out at80ºC,150ºC,and300ºC with different Fe/C ratios (0.1and0.5)and L/C ratios(5and10).The effects of time and temperature,as well as the impact of an increased availability of the Fe metal,were investigated. Special attention was paid to the impact of the distance to the Fe plate on the nature of the run products. MATERIALS,METHODS,AND ANALYTICALTECHNIQUESBatch experiments were conducted at80,150,and 300ºC in dilute chlorine solutions(NaCl,CaCl2)having ionic strength and major cation compositions close to the natural waters present in sediments and similar to that of experiments described by Guillaume(2002)and Guillaume et al.(2003,2004).The starting product was a Wyoming bentonite(MX80)consisting of >85wt.%of smectite.The smectite is a montmorillonite and the half structural formula(<2m m fraction of the bentonite)given by Guillaume et al.(2003)is:(Si3.98Al0.02)(Al1.55Mg0.28Fe II0.08Fe III0.09)O10(OH)2Na0.18Ca0.10 Bentonite was placed in contact with Fe oxides (magnetite)and Fe metal in autoclaves over periods ranging between3and12months.The L/C mass ratios were5or10(rather less than those used in previously published works,see Table1),and Fe(powder of metal Fe+magnetite)/clay ratios were0.5or0.1.A plate of metallic Fe(~1cm2)was added in all experiments.The starting products were introduced into the autoclave under Ar atmosphere.Details of the experimental procedures have been published elsewhere(Guillaume et al.,2003,2004;Charpentier et al.,2006).The mineralogical and chemical evolutions of the clays w e r e s t u d i e d b y X-r a y D i f f r a c t i o n(X R D), Transmission Electron Microscopy(TEM)using High Resolution and Electron Dispersive Spectroscopy(HR-and EDS-TEM),and micro-Fourier Transform Infrared (m FTIR)spectroscopy.Analysis of particles was coupled with HRTEM images so that particle edges could be observed.X-ray diffraction,carried out on air-dried and glycolated preparations of samples,was used to investigate the swelling feature of the clays and to discriminate the main run products(saponite,vermiculite,and chlorite or berthierine).Serpentine group minerals and Fe-rich chlorite were extremely difficult to distinguish by XRD (because of the similarities of their chemistry and structureÀHRTEM was used to help in the identifica-tion;and because of the small amount of newly formed phases in comparison to the unmodified starting product). Due to the number of run samples,crystal-chemical trends are presented as they,in particular,show clearly the increasing incorporation of Fe in newly formed phases, the permanence or otherwise of exchangeable cations typical of smectite-type or vermiculite layers,and the changes in the occupancy of the tetrahedral site by Si which was the best indicator of the smectite to non-swelling(chlorite or berthierine)conversion.The FTIR spectra were obtained in the mid-IR region (4000À600cmÀ1)by micro-Fourier Transform Infrared (m FTIR)spectroscopy using a Bruker IFS55spectro-meter associated with a Bruker A590microscope.All measurements were conducted in transmission mode on samples deposited on ZnSe slides.The diameter of the beam was60m m and the spectral resolution was2cmÀ1. The recording time was~1min.Each spectrum was processed using the OPUS program(#Bruker).RESULTSEffect of Fe/clay ratio80ºC experiments.At80ºC for a L/C ratio of10and an Fe/C ratio of0.1,run products were characterized by slight decreases in Si content and interlayer charge (Na+K+2Ca)together with a slight increase in Fe content(Figure2).The duration of experiment had no effect on the reaction and a possible equilibrium was obtained after3months.In contact with the Fe plate (large Fe/C ratio)and for a short duration(3months), clay particles were richer in Fe(filled triangles in Figure2)than the bulk run product.A more significant evolution was observed for a greater Fe/C ratio(0.5)and for a smaller L/C ratio(5) (gray triangles in Figure2):these experimental condi-tions favored the crystallization of an Fe-rich and Si-and Ca-poor phase.The duration of this experiment was important(12months)but equilibrium was quickly obtained for shorter durations.The XRD patterns showed that the fine fraction(<4m m)of this last run product(Figure3)was mostly composed of a swelling clay-like smectite.Additional saturations of this fractionVol.58,No.2,2010Effects of pH and Fe/C and L/C ratios on the transformation of smectite283with Li and Mg before XRD analysis confirmed that a significant proportion of the run product was fully expandable.The run product could be thus a mixture of asmectite and an F e-rich 14A˚chlorite (chamosite type)or a 7A˚clay (berthierine type)since the global interlayer charge of the particles decreases.The disagreement between XRD and EDS-TEM results could be explained by a mechanical enrichment in smectite particlesduringFigure parison of the crystal-chemistry of the clay phase for experiments carried out at 80ºC with a L/C ratio of 10or 5,and an Fe/C ratio of 0.1or 0.5.The durations were 3months (open triangles),6months (open diamonds),9months (open squares),or 12months (gray triangles).Filled triangles correspond to particles sampled on the Fe plate.The circle corresponds to the range of values of the starting MX80bentonite Si vs.Na +K +2Ca;Fe (total Fe converted to Fe 3+)vs.Mg;Ca vs.Na;and Fe/(Fe +Mg)vs.Si diagrams plotted from EDS-TEM analyses and structural formulae calculated on the basis of 11oxygens (diagrams after Grauby et al.,1993).Figure 3.XRD patterns recorded from the fine fraction (<4m m)of the run product obtained in the 12-month experiment carried out at 80ºC in the presence of a large Fe/C ratio (0.5)and L/C ratio of 5:(a)air-dried sample (AD);(b)glycolated sample (EG:solvation with ethylene glycol vapor at room temperature over 24h);and (c)heated sample (H:4h at 550ºC).The index of reflectionscorresponds to d hkl in A˚.The XRD data were collected using a D8Bruker diffractometer with CoK a 1radiation (l =1.7902A ˚).The general operating conditions were 35kV accelerating voltage,45mA intensity,step-scanning at 0.035º2y intervals,3s counting time,3À40º2y for oriented powder.284Mosser-Ruck et al .Clays and Clay Mineralsthe separation of the <4m m fraction for X-ray analysis.A HRTEM image of the bulk of this run product showsboth numerous long flakes typical of smectite (10A˚interlayer)and several shorter and thicker particles witha 7A˚interlayer (Figure 4)and confirmed the coexistence of at least two types of clay in the runsample.The 7A˚Fe-rich phase was,therefore,mostly found for experiments with a large Fe/C ratio.The 7A˚phase had a composition close to that of berthierine (gray triangles in Figure 2)and its abundance decreased to undetectable amounts in experiments carried out with smaller Fe/C ratios.Clay particles of this run product were also sampled at the contact with the Fe plate and analyzed by FTIR spectroscopy.The IR spectrum (Figure 5)was compared to that of the startingNa-montmorillonite (MX80).In the spectra for both the starting montmorillonite and the run product,bands o b s e r v e d b e t w e e n 3800À3100c m À1a n d 1700À1500cm À1were assigned to OH-stretching vibra-tions from clay minerals and water and to water-bending vibrations,respectively.The spectrum of the run product showed several new bands at 1410,1385,1356,712,and 667cm À1.By comparison with literature data (Saumagne and Josien,1962;Toppani et al.,2005),these bands were assigned to stretching (between 1410and 1356cm À1)and bending modes (712and 667cm À1)of the CO 32Àgroup.Otherwise,the bending band fitted at 1585cm À1was assigned to strongly bound water.This kind of FTIR spectrum was very similar to that obtained by Toppani et al.(2005)for complex hydrated carbonates.The starting MX80bentonite containing ~2%carbonates would be the source of CO 2in the experimental system,allowing the formation of bicar-bonates at the contact with the Fe plate.300ºC experiments .The impact of the Fe/C ratio on the transformation of montmorillonite at three different experiment durations (3,6,and 9months)was studied (Figure 6).Experiments with a small Fe/C ratio (0.1,diamonds in Figure 6)and with a large Fe/C ratio of 0.5(squares)were compared.The EDS-TEM analyses showed that the increase in Fe/C ratio enhanced the chemical evolution.The decrease in Si content was more significant (Si <3for a half formula based on 11oxygens)in run products obtained in experiments with an Fe/C ratio of 0.5for all durations and in the 9month experiment only when the Fe/C ratio was 0.1.A long experiment (9months)and a small Fe/C ratio had the same impact on the tetrahedral occupancy as a short experiment (3months)and a large Fe/C ratio.Different Fe/C ratios also yielded distinct octahedraloccupanciesFigure 4.HRTEM analysis of the run product obtained from the 12-month experiment carried out at 80ºC in the presence of a large Fe/C ratio (0.5)and L/C ratio of5.Figure 5.IR spectra in transmission mode of the starting MX montmorillonite and the run product sampled at the contact of the Fe plate in 80ºC,12months,L/C =5,Fe/C =0.5experiment.Vol.58,No.2,2010Effects of pH and Fe/C and L/C ratios on the transformation of smectite 285of the run clays.In the small Fe/C-ratio (0.1)experi-ments,both Fe and Mg enrichments were observed in run products (arrows in Figure 6)whereas a large Fe/C ratio in the experimental medium led to a significant Fe enrichment of clays only.Interlayer occupancy of the run products was generally depleted both in Ca and Na for all run products.The new data obtained at 300ºC from greater Fe/C-ratio experiments were in good agreement with results obtained by Guillaume et al.(2003)and Charpentier et al.(2006)who demonstrated that the chemical evolution of the montmorillonite in MX80bentonite depends on the distance to the Fe plate and consequently on the availability of Fe in the medium.Iron enrichment in particles sampled near and at the contact with the Fe plate (where the Fe/C ratio was large)was always far more significant.Effect of temperatureOne of the most important parameters controlling the transformation of smectite is temperature.Its effect was also studied in the presence of a metallic Fe plate and under an Fe/C ratio of 0.5and a L/C ratio of 5.Three long duration experiments (12months)were conducted at 80ºC,150ºC,and 300ºC.They showed that the increase in temperature both enhanced Si depletion and Fe enrichment of the run clays (Figure 7).The interlayer charges were different in newly formed clays yielding to the formation of Fe-rich saponite at 300ºC (Na +K +2Ca ~0.3to 0.4)and the crystallization ofa 7A˚phase mixed with starting smectite at a temperature of <150ºC (Na +K +2Ca <0.2).In the greater Fe/C-ratio (0.5)experiments,no zeolite by-products were observed,regardless of the temperature.DISCUSSION AND CONCLUSIONSMineralogical transformations and sequencesFrom literature data (Table 1)and results presented in the present paper,at 80ºC and 150ºC,in the presence of Fe (powder and plate)and Fe oxides (magnetite),and for specific experimental conditions (large L/C ratio and Fe/C <0.5),montmorillonite evidently remains the pre-dominant clay mineral in run products.Under any pH (neutral or alkaline),similar weak enrichment of Fe and depletion of Si were observed in the clays.At 300ºC,vermiculite was predominant,associated with Fe-rich trioctahedral smectite (saponite-type)in alkaline condi-tions (Charpentier et al.,2006)whereas Fe-rich chlorites associated with Fe-rich trioctahedral smectite (saponite-type)were identified in neutral conditions (Guillaume et al.,2003,2004).The experimental crystallization of Mg-vermiculite after smectite in alkaline solutions was also mentioned by Chermak (1992).In the study of Charpentier et al.(2006),the formation of Fe-rich vermiculites seemed to be favored by the initially alkaline conditions and the presence of Fe metal,all other conditions being equal in comparison with the 300ºC experiments reported by Guillaume et al.(2003).In all cases,chemical zoning was observed from the very near contact with the Fe plate toward the bulk clay,usually a decrease in Fe in the run products sometimes in favor of Mg (at 300ºC).The occurrence of quartz,feldspars,magnetite,and zeolites as reaction by-products in all experiments is consistent both with thermodynamic modeling predic-tions (Cathelineau et al.,2001;Kluska et al.,2002;Montes et al.,2005)and data from other experiments on bentonites (Table 1).The simplified conversion ofaFigure parison of the crystal chemistry of the clay phases for 3-,6-,and 9-month experiments carried out at 300ºC with a L/C ratio of 10,and different Fe/C ratios (0.1or 0.5).Si vs.Na +K +2Ca;Fe (total Fe converted to Fe 3+)vs.Mg;Ca vs.Na;and Fe/(Fe +Mg)vs.Si diagrams are plotted from EDS-TEM analyses and structural formulae calculated on the basis of 11oxygens (diagrams after Grauby et al.,1993).286Mosser-Ruck et al .Clays and Clay Mineralsmontmorillonite to a chlorite of chamosite-type (Si 3Al)(Al)(Fe 2+,Mg)5O 10(OH)8(or berthierine which has nearly the same chemical formulae based on 5oxygens)yields to the expulsion of silica,which crystallizes either as quartz or other silicates (feldspars,zeolites)depending on the availability of cations in solution.For the material studied,it can be expressed as follows:2(Si 3.98Al 0.02)(Al 1.55Mg 0.28Fe II 0.08Fe III0.09)O 10(OH)2Na 0.18Ca 0.10+Montmorillonite MX80(Sm)7.039Fe 2++10.76H 2O +0.18e À?1.57(Si 3Al)(Al )(Fe II 4.7Mg 0.3)O 10(OH)8+Chamosite or 3.14berthierine (chl)0.2Ca 2++0.36Na ++3.25SiO 2(aq.)+0.089Mg 2++12.96H +(1)As the dissolution of Fe metal is expressed as:Fe 0+2H 2O ?H 2+2OH À+Fe 2+(2)and reduction of Fe 3+to Fe 2+is expressed as:Fe 3++ÝH 2?Fe 2++H +(3)the combination of reactions 1,2,and 3results in:7.039Fe 0+11.698H 2O +2Sm ?1.57Chl +0.2Ca 2++0.36Na ++3.25SiO 2(aq.)+0.089Mg 2++6.949H 2+0.938OH ÀThe production of H +in reaction 1partly compen-sates the production of OH Àdue to the dissolution of Fe (reaction 2),thus explaining the near-neutral pH of most experimental solutions (measured after quenching).The availability of silica and cations in solution led to the formation of feldspars or zeolites.The presence of bicarbonates or carbonates at the contact of the Fe plate in one experiment is analogous to corrosion products of the steel canister reported in the literature (e.g.Schlegel et al.,2008)and the results of geochemical modeling of Fe-clay interactions (Bildstein et al.,2006;Savage et al.,2010).Discrete calcite originally present in the bentonite probably dissolved at the beginning of the experiment.The Ca 2+ions released can enter the interlayer space of smectite and HCO 3Àcan combine with other cations as Fe 2+at the contact of the Fe plate to form hydroxy-carbonate (or carbonate)species.Neutral to high pH values at the contact with the Fe plate (as shown by the presence of magnetite in some experiments)and a small P CO 2could favor the formation of hydroxycarbonates.Finally,the mineralogical sequences depend on the availability of Fe in solution and on the starting pH of the solution.Under neutral pH conditions,the sequence of newly formed mineral assemblages is thus as follows:(1)dioctahedral smectite (di-Sm)>Fe-rich di-Sm for small Fe/C ratios and small L/C ratios,or berthierine-like mineral if the Fe/C ratio is >0.5at 80ºC or 150ºC;(2)di-Sm >Fe di-Sm >Fe-saponite >trioctahedral chlorite +feldpars +zeolite,at 300ºC.Experiments carried out with a starting pH of 12led to the following mineral sequences:(1)di-Sm >Fe di-Sm +palygorskite at 80ºand 150ºC,(2)di-Sm >vermiculite (ÔFe saponite)+mordenite at 300ºCThe possible mineral zonings are,therefore,distinct when the fluids come from the geological barrier or from concrete.Comparison with natural occurrencesAn additional line of comparison is provided by the consideration of natural assemblages and the following transitions:the berthierine-to-chlorite conversion (Iijima and Matsumoto,1982;Hillier and Velde,1992),the di-to trioctahedral smectite transition (Inoue,1987;Inoue and Utada,1991),and the smectite-to-chlorite conversion (Bettison-Varga and Mackinnon,1997;Robinson et al.,2002;Schiffman and Staudigel,1995).The temperature range of stability of chlorite is rather large,between 110ºC and 420ºC (Iijima and Matsumoto,1982;Cathelineau and Izquierdo,1988;Hillier and Velde,1992;Buatier et al.,1993;Aagaard et al.,2000)indicating a potential formation of chlorite minerals at temperatures close to those of interest in wastedisposal.Figure parison of the crystal chemistry of clay particles obtained from the 12-month experiments carried out at 80ºC (open circles),150ºC (gray diamonds),and 300ºC (gray squares)in the presence of an Fe/C ratio of 0.5and an L/C ratio of 5.Vol.58,No.2,2010Effects of pH and Fe/C and L/C ratios on the transformation of smectite 287。
