Clay Surfaces (eBook)

Cover 1
Preface 5
Contributors 8
Contents 11
Chemical Modification of Clay Surfaces 13
Introduction 14
Simple Hydroxides Derivatives 19
Surface Adsorption 19
Exchange of Hydroxyl Ions 20
Interlayer (or Surface) Grafting 20
Grafting of Ethylene Glycol and Glycerol into Brucite [33] 20
Solvation Reaction of the Interlayer Hydroxyl Groups 24
Oxidation-Reduction Reactions 24
Reaction of Gibbsite with Lithium Chloride 25
Hydroxysalts Derivatives 25
Ionic and Solvent Exchange Reactions 25
Hydroxyl Ions Substitution + Ionic Exchange Reactions 26
Grafting Reaction [54-57] 26
Grafting of Copper(II) Hydroxide Acetate with Benzoic Acid [54] 26
Exfoliation Reactions 31
Layered Double Hydroxide Derivatives 32
Surface Adsorption Reactions 32
Exchange + Grafting Reactions 32
Grafting of Layered Double Hydroxide (LDH) with Ethylene Glycol [40] 32
Thermal Reactions 38
Iron Nanoparticles Embedded in Al2O3-ZnO Matrix [86] 38
Exfoliation Reactions and Preparation of Nanocomposites 41
Exfoliation of a Layered Double Hydroxide and Reaction with Poly(Ethylene oxide) [89] 41
Kaolinite Derivatives 44
Direct Solvation (Intercalation) 44
Intercalation of Dimethylsulfoxide (DMSO) 44
Intercalation by Displacement [112-117] 46
Displacement of DMSO by Benzamide [112] 46
Direct Grafting 51
Reaction with Phenylphosphonic Acid [105] 51
Grafting by Displacement 53
Grafting of Ethylene Glycol by the Displacing of Dimethylsulphoxide 53
Mechanochemical Modifications [109-111] 54
Intercalation of Urea and Preparation of Hydrated Kaolinite [111] 54
Smectite Derivatives 59
Cationic Exchange Reactions 60
Thermal Reactions 60
Grafting Reactions 61
Exfoliation and Preparation of Nanocomposites 61
Concluding Remarks 62
Aknowledgements 62
References 63
Electrokinetic Behavior of Clay Surfaces 69
Introduction 70
Electrokinetic Properties 70
Zeta Potential 70
Potential Determining Ions 72
Surface Potential 72
Origin of Surface Charge 72
Electrokinetics of Clay Minerals 74
Layer Charge Density of Clay Minerals 74
Structure of Clay Minerals 74
Kaolin 75
Smectites 82
Palygorskite and Sepiolite 90
DLVO Theory 94
Interaction Energy Curves 94
Application of DLVO Theory to Clay Particles 97
References 99
Surface Thermodynamics of Clays 102
Thermodynamics of Clay Surfaces by Surface Tension 103
LW Interactions 104
AB (Polar) Interactions 104
Determination of Contact Angle 105
Surface Tension Components - The Young- Dupre Equation 106
Hydrophobic and Hydrophilic Nature of Clays - Relation to Interparticle Free Energy 109
Hydrophobicity of Talc and Pyrophylite 111
Immersion Enthalpy Studies on Clays 112
Adsorption Enthalpy and Entropy Studies on Smectite Surfaces 113
DKR Equation 115
Adsorption of Long Chain Quaternary Amine Cations 116
Thermodynainic Studies of Adsorption on the Modified Clay Surfaces 120
Conclusions 126
Acknowledgements 127
References 127
Phenomenology of Water Adsorption at Clay Surfaces 130
Introduction 131
Nomenclature 132
Surface Sites 135
Particle Size, Shape, and Surface Area 136
Thermodynamics 137
Surface Free Energy 137
Adsorption 138
Surface Excesses: The Problem of Dividing Surfaces 139
Adsorption Isotherms 140
Adsorption Enthalpies 142
Wettability 142
Experimental Methods 144
Adsorption Isotherms 144
Adsorption Calorimetry 144
Gas Chromatography 145
Surface Infrared Spectroscopy 146
TSDC 146
Theoretical Methods 146
Trends 148
Surface Energy 148
Chemical Reactivity Indexes 150
Adsorption Enthalpies 153
Difficulties of Interpretation 155
Estimation of the Quantitative Surface Energy Relative to the Cations 155
Estimation of the Enthalpy of Adsorption onto One Face of a Sheet 156
Estimation of the Ratio between Enthalpy and Entropy 157
Position and Distance of the Water Molecules 158
Swelling 158
Summary 159
References 160
A Worksheet Model for Adsorption/Desorption of Ions on Clay Surfaces 165
Introduction 166
Description of the Model 169
The Sorbent 169
Cations in Suspension 171
Cations Bound to the Surface of the Clay (Stern Layer) 172
Cations in the Diffuse Layer 175
Mass Balance of Ion i 177
Evaluating the Potential at the Surface and y(0) 179
Computational Procedure 181
Activity Coefficients in the Diffuse Layer 182
Debye Length 182
Qualitative Influence of the Double Layer 184
Rate of Formation of a Z-Valent Site 185
First Derivative of y(x) 186
Examples 187
Na+/Ca++ Exchange Over a Montmorillonite Clay 187
Adsorption of an Organic Monovalent Dye, upon Increasing Ionic Strength 191
Summary 193
References 193
Raman and Infrared Spectroscopic Stuides of Kaolinite Surfaces Modified by Intercalation 196
Introduction 197
Modification of Kaolinite Surfaces 199
Vibrational Spectroscopy of Kaolinites 199
Modification of Kaolinite Surfaces through Mechanochemical Activation 200
Kaolinite Adsorbed and Intercalated Formamide - Application of the Controlled Rate Thermal Analysis Experiment 204
CRTA Treated Hydrazine Intercalated Kaolinite 207
Intercalation of Mechanochemically Activated Kaolinite Intercalated with Potassium Acetate 214
Deintercalation of Hydrazine Intercalated Kaolinite 218
Conclusions 226
References 226
Nuclear Magnetic Resonance Spectroscopy of Molecules and Ions at Clay Surfaces 228
Introduction 229
Theory 229
Nuclear Spin Interactions 229
Relaxation 231
Self-Diffusion 231
NMR Studies of Aqueous Clay Suspensions 231
Quadrupolar Splitting 232
Self-Diffusion 235
Relaxation 236
NMR Studies of Solid Clayey Materials 241
Interlayer Inorganic Cations 241
Intercalated Organic Cations 244
Intercalated (Adsorbed) Molecules 248
Conclusions 254
Acknowledgments 255
References 255
Pesticide-Clay Interactions and Formulations 259
Introduction 260
Pesticides 261
The Pesticide Sorption Process 262
Pesticide-Clay Interactions 263
Pesticide Interactions with Modified Clays 268
Pesticide-Clay Formulations 271
Summary and Conclusions 274
References 274
Pharmaceutical and Cosmetic Applications of Clays 279
Introduction 280
Structure and Texture 281
Use in Pharmaceutical Formulations 283
Pharmaceutical Denominations 283
Pharmaceutical Specifications 283
Use as Excipients 285
Solid Dosage Excipients 285
Liquid and Semisolid Dosage Excipients 287
Use of Clay Minerals as Active Substances 289
Antidiarrhoeal Uses 290
Gastrointestinal Protector 290
Antacid Uses 291
Anti-Inflammatory and Antiseptic Purposes 291
Topical Applications 291
Other Uses 291
New Uses in Modified Drug Delivery Systems 292
Use in Cosmetics 293
Topical Use: Clays in Spas 294
Concluding Remarks 295
Acknowledgements 296
References 296
Removal of Metals by Natural and Modified Clays 302
Introduction 303
Retention of Metals by Clays 304
Special Analysis: Retention of Chromium by Clays 308
Chromium (III) Solutions 309
Retention of Chromium from Solutions by Clays 312
Influence of Chromium (III) Species on Clays 312
Influence of the Chromium Added 314
Influence of the Types of Clays 315
Effects of Thermal Treatment on Cr-Clays 318
Heating up to 450°C to Obtain Cr-PILCs 319
Heating at High Temperatures 321
Retention Chromium from Wastewater by Clays 324
Can We Use Clays to Improve the Environment? 328
Acknowlegement 328
References 329
Catalytic and Adsorption Properties of Modified Clay Surfaces 333
Introduction 334
Structure of Smectite Clay Minerals 334
Isomorphous Substitution 335
Broken Edges 335
Layer Charge 335
Cation Exchange Capacity (cec) 336
Determination of the CEC 337
Cation Migration 337
The Hydration and Swelling Capacity of Clays 338
Acidity of Clays 339
Determination of the Surface Acidity 339
Acid Activation of Clays 339
Ion-Exchange Activation 341
Metal Cations 341
Pillared Clays 341
Clay-Organic Cation Interactions 343
Nature of the Organocation 343
Organo-Clay Complexes 344
Ion Exchange 344
Ion-Dipole and Coordination 345
Hydrogen Bonding 345
Van der Waals Forces 345
Adsorption Behavior 345
Acid-Activated Organoclays (aaocs) 347
Conclusions 351
Acknowledgements 351
References 351
Preparation of Layered Double Hydroxides 357
Preparation of Layered Double Hydroxide with Interlayer Carbonate 358
Mg and Al Layered Double Hydroxide with Interlayer Carbonate 359
Zn and Al Layered Double Hydroxide with Interlayer Carbonate 367
Intercalation of Organic Anions to ldh 369
Intercalation by Rehydration Method 369
Intercalation of Organic Anions by the Coprecipitation Method 376
Intercalation of Naphthalenedisulfonate at the Interlayer Region of Mg and Al Double Hydroxide 376
Intercalation of 9,10-Anthraquinonedisulfonates at the Interlayer Region of Mg and Al Double Hydroxide 380
References 383
Polyoxometalate Complexes of Layered Double Hydroxides 386
Introduction 387
Structural Characteristics of POM-LDH 391
Synthesis Method of POM-LDH 396
Organic-Anion-Pillared Precursor-Exchange (OPE) Method 396
Reconstitution Method 397
Swelling Agent (SA) Method 397
Direct Coprecipitation (DC) Method 398
NO3-LDH Exchange (LE) Method 398
Phase-Transfer Method Using Surfactant 398
Catalysis by POM-LDHs 400
Acid and Redox Catalysis 400
Photocatalysis 405
Concluding Remarks and Expectation 412
Reference 412
Cationic and Anionic Clays for Biological Applications 415
Introduction 416
Cationic Clays 416
Structure and Classification 416
Preparation 418
Pharmaceutical Applications 419
Cosmetic Application 421
Agricultural Applications to Animal Feed and Pesticides 422
Anionic Clays: Layered Double Hydroxides 423
Structure and Classification 423
Preparation 425
Pharmaceutical Applications 426
Cosmetic Applications 430
Agricultural Applications 433
Conclusive Remarks 433
References 434
Environmental remediation Involving Layered Double Hydroxides 437
Introduction 438
Environmental Challenges 438
Presentation of Layered Double Hydroxides 438
Physical and Chemical Properties of LDHs in Relation with Remediation Anion Exchange Capacity 439
Acid-Basic Properties 440
Shape and Morphology 441
Surface and Porosity Properties 442
Remediation of Inorganic Contaminants by Exchange/Adsorption Process 442
Removal of Oxoanions 443
Removal of Heavy Metals 443
Removal of Heavy Metals as Oxometallate Anions 443
Removal of Heavy Metal as Cations 445
Removal of Nuclear Wastes 445
Adsorption of Greenhouse Gases 446
Remediation of Organic Pollutants by Adsorption/Exchange Process 447
Adsorption of Organic Molecules by LDHs 447
Removal of Pesticides and Related Organic Compounds by LDHs 448
Adsorption of Phenol 448
Adsorption of Pesticides 449
Dye Removal 450
Adsorption of Humic Substances 452
Adsorption by Pillared Anionic Clays 452
Adsorption by Organoclays 452
Adsorption/Intercalation of Surfactants by LDHs : through Organoclays Adsorbents 452
Adsorption Properties of Surfactants Modified LDHs 453
Adsorption by Calcined LDHs 454
The Calcinations-Reconstruction of LDHs 454
Adsorption by Calcined LDHs 454
Catalytic Remediation by LDHs 455
Catalytic Properties of LDH uses for Environmental Remediation 455
Catalytic Decomposition of Organic Molecules 455
Total Oxidation 455
Partial Oxidation of Organic Molecules 456
Catalytic Decomposition of NOx and SOx 456
NO and N2O Decomposition 457
NO and N2O Selective Catalytic Reduction 459
SOx Decomposition 459
Photocatalytic Decomposition by LDH's 460
Conclusions 461
References 461
Layered Double Hydroxide / Polymer Nanocomposites 471
Introduction 472
Brief Description of LDH Material 473
Natural Occurancy and Chemical Composition 473
Layer Charge Density 473
Colloidal and Exfoliation Properties 474
Synthetic Pathways for the Assembly 475
Special Cares 476
The Methods 476
A Non Exhaustive List 479
Characterization of the Two-Components Materials 479
The Host Structure 479
An Endotactic Reaction 481
Illustration of the Endotactic Process : the Case of Inorganic Polymer 483
State of the Polymer 484
Measure of the Interaction 486
Textural Properties 488
Behaviour in Temperature 488
Domains of Application 492
Organic Inorganic Hybrid Assembly 492
Adsorption, Sensors and Electrochemical Sensors 492
Biological and Environmental Applications 492
Carbonaceous Replica 493
Cement-Related Materials 495
Towards LDH Nanofillers 495
Enhanced Mechanical Properties 495
Flame-Retardant Properties 498
Bio and Bio-Inspired LDH Nanocomposites 498
The State of the Art 498
Characterization and Processings 499
Applications 499
Future Developments 500
Summary 502
Acknowledgments 502
References 502
Catalytic Properties of Hydrotalcite-Type Anionic Clays 508
Introduction 509
Precursors of Catalyst Supports 510
Catalysts for Organic Syntheses 513
Catalysts for Hydrogenation or Hydrogenolysis Reactions 521
Catalyst for Environmental Applications 526
Catalysts for Advanced Natural Gas Exploitation 534
Concluding Remarks 545
Acknowledgments 546
References 546
Index 559