Handbook of Clay Science (eBook)
1246 Seiten
Elsevier Science (Verlag)
978-0-08-045763-5 (ISBN)
The Handbook of Clay Science aims at assembling the scattered literature on the varied and diverse aspects that make up the discipline of clay science. The topics covered range from the fundamental structures (including textures) and properties of clays and clay minerals, through their environmental, health and industrial applications, to their analysis and characterization by modern instrumental techniques. Also included are the clay-microbe interaction, layered double hydroxides, zeolites, cement hydrates, genesis of clay minerals as well as the history and teaching of clay science. No modern book in the English language is available that is as comprehensive and wide-ranging in coverage as the Handbook of Clay Science.
In providing a critical and up-to-date assessment of the accumulated information, this will serve as the first point of entry into the literature for both newcomers and graduate students, while for research scientists, university teachers, industrial chemists, and environmental engineers the book will become a standard reference text.
* Presents contributions from 66 authors from 18 different countries who have come together to produce the most comprehensive modern handbook on clay science
* Provides up-to-date concepts, properties, and reactivity of clays and clay minerals in a one-stop source of information
* Covers classical and new environmental, industrial, and health applications of clays, as well as the instrumental techniques for clay mineral analysis
* Combines geology, mineralogy, crystallography with physics, geotechnology, and soil mechanics together with inorganic, organic, physical, and colloid chemistry for a truly multidisciplinary approach
The first general texts on clay mineralogy and the practical applications of clay, written by R.E. Grim, were published some 40-50 years ago. Since then, a vast literature has accumulated but this information is scattered and not always accessible. The Handbook of Clay Science aims at assembling the scattered literature on the varied and diverse aspects that make up the discipline of clay science. The topics covered range from the fundamental structures (including textures) and properties of clays and clay minerals, through their environmental, health and industrial applications, to their analysis and characterization by modern instrumental techniques. Also included are the clay-microbe interaction, layered double hydroxides, zeolites, cement hydrates, genesis of clay minerals as well as the history and teaching of clay science. No modern book in the English language is available that is as comprehensive and wide-ranging in coverage as the Handbook of Clay Science.In providing a critical and up-to-date assessment of the accumulated information, this will serve as the first point of entry into the literature for both newcomers and graduate students, while for research scientists, university teachers, industrial chemists, and environmental engineers the book will become a standard reference text.* Presents contributions from 66 authors from 18 different countries who have come together to produce the most comprehensive modern handbook on clay science* Provides up-to-date concepts, properties, and reactivity of clays and clay minerals in a one-stop source of information* Covers classical and new environmental, industrial, and health applications of clays, as well as the instrumental techniques for clay mineral analysis* Combines geology, mineralogy, crystallography with physics, geotechnology, and soil mechanics together with inorganic, organic, physical, and colloid chemistry for a truly multidisciplinary approach
Front cover 1
Title page 4
Copyright page 5
Dedication 6
Table of contents 8
List of Contributors by Country of Residence 12
Acknowledgements 14
Contributing Authors 16
Forward 20
1 General Introduction: Clays, Clay Minerals, and Clay Science 24
Aim and Scope 24
Clay 26
Clay Mineral 28
Distinction between Clay and Clay Mineral 31
Clay Mineral Properties 31
Associated Minerals 32
Associated Phases 32
Other Solids with Similar Properties 33
Clay Mineral Particles and Aggregates 34
Clay Minerals and Environment 34
Alternative Concepts of Clay Minerals 35
Clay Science 39
Concluding Remarks 39
References 39
2 Structures and Mineralogy of Clay Minerals 42
General Structural Information 42
Layer Charge (X) 47
Polytypism 47
Mixed-Layer Structures 47
The 1:1 Layer 49
Dioctahedral 1:1 Minerals: The Kaolin Group 49
A. Kaolinite 50
B. Dickite 53
C. Nacrite 54
D. Halloysite 55
E. Hisingerite 56
Trioctahedral 1:1 Minerals: The Serpentine Group 56
The 2:1 Layer 58
Pyrophyllite, Talc, and Related Minerals 59
True and Brittle Micas 61
Illite 62
Smectites 63
Vermiculite 66
Chlorite 67
Illite–Smectite and other Interstratifications between Dioctahedral Non-Expandable and Expandable 2:1 Layers 70
Allophane and Imogolite 71
Palygorskite and Sepiolite 79
References 92
3 Surface and Interface Chemistry of Clay Minerals 110
Surface Atoms 110
Surface Structures and Properties 112
The Neutral Siloxane Surface 112
Constant Charge Sites (Siloxane Surface with Permanent Charge) 113
The Hydroxyl Surface 114
Hydrophobic–Hydrophilic Character of Clay Mineral Surfaces 117
Clay–Water Interactions 119
Structure and Properties of Water Sorbed to Clay Mineral Surfaces 120
Influence of Water on Clay Mineral Structure 121
Surface Chemistry in Aqueous Dispersions 122
Preliminary Considerations 122
Spectroscopy 123
Monomers, Dimers and Aggregates 124
Organisation of Clay Mineral Particles and Molecules 127
Self-Assembling 127
Langmuir–Blodgett Technique 128
References 132
4 Synthetic Clay Minerals and Purification of Natural Clays 138
Methodology 138
Synthesis from Very Dilute Solutions 139
Solid-State Reactions 139
Hydrothermal Synthesis 140
Germination Process 140
Crystal Growth 141
Role of temperature 141
Role of pH 141
Role of time: crystallization versus crystallinity 142
Intermediate phases 143
Characterization of Synthetic Clay Minerals 143
Synthesis of Specific Clay Minerals 144
Micas 144
Smectites 145
Kaolinite 146
Sepiolite 148
Purification of Clays 148
Purification Procedures 149
Decomposition of Carbonates 150
Recommended procedure 150
Dissolution of (Hydr)oxides 150
Recommended procedure 151
Oxidation of Organic Materials 151
Recommended procedure 152
Dissolution of Silica 152
Removal of Remaining Salt by Dialysis and Fractionation 152
A Simplified ’Gentle’ Purification Method 153
Na+-exchange 153
Washing 153
Recommended procedure 153
A Pilot Purification Technique 154
Conclusions 154
References 154
5 Colloid Clay Science 164
Clay Mineral Particles 164
Particle and Aggregate Structure 164
Layer and Edge Charges 165
Clay Minerals in Water 169
Hydrates of 2:1 Clay Minerals 169
Structure of the Hydrates 171
Colloidal Dispersions 173
Electrokinetic Properties 175
Preparation of Colloidal Dispersions 177
Fractionation of Clay Dispersions 177
Dispersions of Kaolins 181
Dispersions of Smectites and Vermiculites 181
H+-Saturated Smectites 183
Determination of Particle Size and Shape in Colloidal Clay Dispersions 183
Coagulation of Colloidal Clay Mineral Dispersions and Mechanisms of Coagulation 185
Coagulation by Inorganic Salts 185
Coagulation of Mixed Clay Mineral Dispersions 193
Influence of Alcohols 197
Influence of Surface Active Agents on Salt Coagulation 197
Stabilisation by Betaines 198
Coagulation by Organic Cations 200
Coagulation by Acids 203
Influence of Poly(hydroxo metal) Cations 204
Clay Mineral-Oxide Interactions 205
Calculation of Interaction Energies 209
Flocculation and Stabilisation by Polymers 215
Flocculation and Stabilisation Mechanisms 215
Flocculation by Polyanions 217
Flocculation by Polycations 219
Peptisation (Deflocculation) of Clay Dispersions by Macromolecules 222
Aggregation of Clay Mineral Particles and Gelation 224
Modes of Aggregation 224
Plasticity 229
Sedimentation and Filtration 230
Sol–Gel Transition 236
Thixotropy 242
Hydrogels of Organo-Clays 243
Gelation in Organic Solvents 243
Layer-by-Layer Aggregation: Clay Hybrid Films 245
Nanoparticle Growth in Clays 246
References 249
6 Mechanical Properties of Clays and Clay Minerals 270
Physico-Chemical Behaviour of Clay Minerals 270
General 270
Clay Mineral-Water Interaction 271
Hydraulic Conductivity 274
Gas Penetrability 274
Ion Diffusivity 276
Mechanical Characteristics of Clays 278
Swelling and Consolidation Properties 278
Rheological Properties 280
References 282
7 Modified Clays and Clay Minerals 284
7.1 Acid Activation of Clay Minerals 286
Properties and Auto-Transformation of H+-Exchanged Clay Minerals 287
Methods of Investigation 288
Acid Dissolution of Smectites 290
Final Solid Reaction Product 295
Optimum Activation Conditions 296
Acid-Activation and Pore Structures 296
Acid Activation of Other Clay Minerals 298
Kaolinite and Metakaolinite 298
Sepiolite and Palygorskite 300
Catalytic Properties of Acid Activated Clay Minerals 300
Smectites 300
Metakaolinite 302
Modified Clay Minerals 303
Conclusion 304
References 304
7.2 Thermally Modified Clay Minerals 312
Freezing of Clay Minerals 313
Effect of Freeze-Drying on the Texture of Clay Minerals 313
Changes in Acidity 313
Changes in Mechanical and Rheological Properties 314
Dehydration of Clay Minerals 314
Changes in Porosity 315
De- and Re-Adsorption of Water 318
Changes in Surface Acidity on Dehydration 318
The Hofmann–Klemen Effect 321
Dehydroxylated Phases 321
Kaolinite Group 321
Serpentines 324
T-O-T Minerals 325
High-Temperature Phases 325
References 326
7.3 Clay Mineral Organic Interactions 332
Intercalation Reactions of Kaolinites 333
Type of Guest Compounds 333
Mechanism of Intercalation 334
Structure of Intercalation Complexes 338
Displacement Reactions 338
Entraining Reactions 339
Intercalation of Alkali Halogenides 339
Grafting Reactions 339
Differentiation of Kaolinites 340
Reactions of 2:1 Clay Minerals 341
Alkylammonium Derivatives 350
Interactions with Cationic Dyes 353
Aggregation of the Adsorbed Dyes 353
Orientation of Intercalated Dye Molecules 355
Reaction with Cationic Complexes 357
Adsorptive Properties of Alkylammonium Clay Minerals 359
Adsorption from Binary Solutions and the Hydrophilic/Hydrophobic Character of Clay Mineral Surfaces 362
Adsorption Excess Isotherms 363
Heat of Wetting 364
Examples 365
Phase Transitions 367
Intercalation of Polymers and Proteins 371
Polymerisation in the Interlayer Space 378
Advanced Applications of Clay Mineral-Organic Complexes 379
References 382
7.4 Clay Minerals and the Origin of Life 402
Clay Minerals as Possible Genetic Material 402
Clay Minerals and the Origin of Biological One-Handedness 404
Clays as Prebiotic Catalysts 406
Clay-Catalysed Synthesis of RNA 407
Polypeptide Formation on Clay Minerals 409
Unresolved Questions and Conclusions 411
References 411
7.5 Pillared Clays and Clay Minerals 416
Pillaring Concept 416
Pillared Clay Minerals and Catalysis 416
IUPAC Definition of Pillaring and Pillared Clay Minerals 417
Host Clay Minerals 419
Pillaring Species 419
(Al13)7+-Pillaring Agent 420
Hydrolysis Products 420
Procedures for Obtaining Al13 421
Factors Influencing Al13 Formation 421
Other Pillaring Agents 422
Mixed Al–M and M–M’ Pillaring Agents 422
Pillaring Agents with More Than Two Cations 423
New Pillaring Agents 423
Pillaring Methods 424
Pillaring in Dilute Dispersions 424
Pillaring in Concentrated Medium 426
Main PILC Characteristics for Different Applications 429
Intercalant Stability Before and After Pillaring 431
Linkage between Pillars and Clay Mineral Layers 432
Conclusions 432
References 433
8 Properties and Behaviour of Iron in Clay Minerals 446
Phases of Iron in Clay Minerals 447
Phase Identification 448
Distribution between Octahedral and Tetrahedral Sites 450
Methods for Iron Reduction 453
Dithionite 453
Bacteria 455
Surface Interactions with Water 457
Clay Mineral–Organic Interactions 465
Layer Charge, Cation Exchange, and Cation Fixation 469
Reduction Potentials and Reaction with Redox-Active Ions 474
Redox Transformation of Nitrate 474
Redox Transformation of Cr6+ 475
Mechanism for Iron Reduction 475
Use of Redox-Modified Smectites in Clay-Modified Electrodes 482
Summary and Conclusions 483
References 484
9 Clays, Microorganisms, and Biomineralization 500
Experimental Aspects 501
Field Investigation 501
Geology 501
Water Chemistry 501
Microbial Mats 501
Laboratory Work 501
Sample Preparation 501
(a) Thin sections 501
(b) Ultra-thin sections 502
Optical Microscopy 502
(a) Bright field image 502
(b) Polarizing microscope image 502
(c) Fluorescence and epifluorescence microscope images 502
X-ray Diffraction (XRD) 502
X-ray Fluorescence Spectroscopy (XRF) 503
Scanning Electron Microscopy (SEM) 503
Transmission Electron Microscopy (TEM) 503
Energy Dispersive X-ray Spectrometry (EDX) 503
Microorganism Culture Methods 503
Bioformation of X-Ray Amorphous Layer Silicates 503
Microbial Mats in Ponds 503
Microbial Mats in Hot Springs 504
Bioformation of Halloysite, Kaolinite and Imogolite 504
Bio-Halloysite from Feldspar in Kutani Glaze 504
Bio-Halloysite Balls from Dam Sediments 509
Bio-Kaolinite and Bio-Imogolite from Weathered Feldspar 509
Bioformation of Smectites Minerals 514
Bio-Nontronite from Iheya Deep-Sea Sediments 514
Bio-Smectite from a Pond of Kasaoka Bentonite Mine 516
Conclusions 519
References 519
10 Clays in Industry 522
10.1 Conventional Applications 524
Industrial Uses 525
Common Clays 525
Kaolins 525
Kaolins as Filler and Coating Particles 525
Kaolins in Ceramics 528
Bentonites 529
Bentonite as Binding Agents 531
Bentonite in Drilling Muds 532
Bentonite in Engineering 534
Bentonite as a Thickener 535
Activated Bentonites, Fuller’s Earth and Catalysis 535
Vermiculites and Micas 537
Talc and Pyrophyllite 539
Palygorskite and Sepiolite 539
Industrial uses of Mixtures of Clay Types 539
Processing Industrial Clays 540
Purification and Fractionation 540
Processing of Kaolins 541
Raw and Activated Bentonites 541
Laboratory Evaluation of Clay Samples 549
Categorization of Clay Resources 551
Categories of Industrial Clays 553
Examples of Different Categories 554
Category 1 554
Category 2 554
Category 3 554
Category 4 555
Role of Categorization in Assessing Industrial Clay Resources 555
Relationship between Category and Annual Tonnage 555
Relationship between Category and Resource Confidence 555
Relationship between Category and Value 556
Relationship between Category and Pre-investment Capital 556
Relationship between Category and Investment Capital 556
The Resource Evaluation Process 556
Other Considerations 558
From Laboratory Scale Testing to Major Plant Scale 558
Level of Applied Technology 559
Losses Associated with Applied Processing Steps 559
Time to Move from Commissioning to Full Production 559
Reducing Risk during Development 560
Conclusions 560
References 560
10.2 Clay Minerals as Catalysts 564
Origin of Activity 565
Low Dimensionality 565
Structural Characteristics Imparting Activity 566
Shape/Size Selectivity 566
Catalysis of Inorganic Reactions 568
Clays as Supports for Reagents 568
Preparation/Activation of Clay Catalysts 568
Summary of Catalytic Activity 570
Brønsted Acid Catalysis 570
Lewis Acid Catalysis 575
Redox Reactions 575
Reactions via Reactive Intermediates 579
Cycloaddition Reactions 580
Clays as Supports 582
Organo-Clays as Phase Transfer Agents 583
Significant Recent Developments 584
Supported Acids 584
Reactions Initiated by Microwave, Ultrasound or Gamma Irradiation 585
Clay Nanocomposites 585
Industrial Situation 585
Conclusions 587
References 588
10.3 Clay Mineral–and Organoclay–Polymer Nanocomposite 606
Exfoliation or Intercalation? 607
Clay Mineral-Polymer Interactions and Structures 609
Preparation of Clay Mineral–Polymer Nanocomposites 610
Direct Intercalation from Solution or Melt 611
In Situ Polymerisation 613
Template Synthesis 614
Host-Guest Compatibility 615
Organoclays 616
Grafting of Clay Minerals 618
Modified Polymers 622
Clay-Polymer Nanocomposites: Properties and Applications 622
Mechanical Properties 623
Tensile Properties 623
Impact Resistance and Ductility 626
Fire Retardancy and Thermal Properties 628
Fire Retardancy 628
Thermal Stability and Expansion 630
Electrical and Electrochemical Properties 630
Gas and Water Permeation 633
Other Properties 634
Polymer Crystallization 634
Degradation During Nanocomposite Processing 634
Conclusions 635
References 636
11 Clays, Environment and Health 646
11.1 Clays and Clay Minerals for Pollution Control 648
Control of Heavy Metal Cations and Simple Cations 649
Practical Applications 650
Mechanisms of Heavy Metal Ion Uptake 651
Relative Affinities of Clays for Different Heavy Metal Ions 653
Ease of Displacement of Heavy Metal Ions from Clays 654
Effects of Clay Modification on Uptake of Heavy Metal Ions 655
Control of Organic and Biological Cations 656
Practical Applications 657
Mechanisms of Uptake of Organic and Biological Cations by Clay Minerals 657
Ease of Displacement of Organic and Biological Cations 659
Control of Non-Ionic Organic Compounds 660
Uptake of NOCs by Organically Unmodified Clay Minerals 661
Organic Modification of Clays and Uptake of NOCs 661
Uptake of NOCs from the Gas Phase by Organo-Clays 661
Uptake of NOCs from Aqueous Solutions by Organo-Clays 662
Practical Applications of Organo-Clays for Control of NOCs 664
Effect of Hydrocarbon Chain Length on Uptake of NOCs by Organo-Clays 665
Demarcation between Short-Chain and Long-Chain QACs 668
Influence of Water on Uptake of NOCs by Organo-Clays 669
Cation Properties and Uptake of NOCs by Short-Chain QAC-Clays 670
Nature of Exchangeable Cations and the Incorporation of Long-Chain QACs into Clays 670
Effect of Amount of Organic Cation on Uptake of NOCs by Long-Chain QAC-Clays 671
Size of Organic Cation and Uptake of NOCs by Long-Chain QAC-Clays 671
Co-adsorption and Uptake of NOCs by Long-Chain QAC-Clays 672
Bonding Modes of Long-Chain QAC in Organo-Clays 673
Properties of NOCs and their Uptake by Organo-Clays 673
Mechanisms of Uptake of NOCs by Organo-Clays 674
NOC Uptake by Long-Chain QAC-Clays and Organic Matter 674
Alternatives to QAC Clay Minerals for Control of NOCs 676
Control of Anions 679
Uptake of Anions by Unmodified Clays 679
Anion Uptake by Clays Modified with Organic Cations 679
Alternative Methods of Modifying Clays for Anion Adsorption 681
Control of Turbidity and Residual Treatment Chemicals 682
Control of Turbidity in Water Treatment 682
Control of Turbidity in Wastewater Treatment 682
Control of Residual Treatment Chemicals 683
Concluding Remarks and Future Prospects 683
Heavy Metal Ions and Simple Cations 683
Organic and Biological Cations 684
Non-Ionic Organic Molecules 684
Anions 685
Turbidity and Use of Colloidal Characteristics 685
Exploitation of Mixtures of Properties 685
Waste Removal and Disposal 686
References 686
11.2 Clays and Pesticides 700
Organo-Clay Formulations 703
Reduction of Volatilization 705
Clay-Micelle Formulations 706
Photostabilization of Pesticides by Organo-Clays 707
Exploiting Clay–Organic Interactions to Enhance the Efficacy of Bipyridyl Herbicides 709
References 710
11.3 Clay Liners and Waste Disposal 716
Waste Categories 716
Mineral Barriers 718
A. Clay Rocks and Clay Minerals 719
B. Zeolites 719
Waste Deposit Multibarrier Systems 720
A. Base Liners 720
B. Surface Liners 721
Conclusions 722
References 724
11.4 Clays and Nuclear Waste Management 726
Buffer Materials 727
Predicted Performance of the ‘‘Clay Buffer’’ 728
Thermally Induced Redistribution of the Initial Pore-Water and Maturation of the Pellet Fill(TH) 731
Uptake of Water from the Rock (THMC) 732
Numerical Modelling 732
Long-Term Physical Performance of the Buffer 736
Chemical Stability of the Buffer 736
References 739
11.5 Clays and Human Health 740
Beneficial Effects of Clays and Clay Minerals 740
A. Historical Background 740
B. Clay Minerals in Pharmaceutical Formulations 742
Use as Active Principles 742
Use as Excipients 743
C. Clay Minerals in Spa and Beauty Therapy 744
Types of Application and Therapeutic Activity 745
Pelotherapy 746
Harmful Effects of Clays and Clay Minerals 750
A. Background Information 750
B. Pathogenicity of Clay Minerals 753
Kaolinite 754
Talc 754
Sepiolite and Palygorskite 755
Illite and Smectites 756
Concluding Remarks 757
References 757
11.6 Clays and Clay Minerals as Drugs 766
Interactions of Clay Minerals with Gastrointestinal Mucus 766
Clay Minerals, Mucosal Barrier, and Gastrointestinal ’Aggressors’ 767
Adsorptive Properties of Clays and Clay Minerals 769
Toxins 769
Pesticides 769
Microorganisms 770
Gas 770
Alimentary Allergy 770
Clay Minerals and Clinical Applications 771
Conclusions 771
References 771
12 Critical Assessment of Some Analytical Techniques 776
12.1 Mössbauer Spectroscopy of Clays and Clay Minerals 778
Historical Background 778
Basic Principles 778
Mössbauer Spectra of Selected Clay Minerals 779
Mössbauer Spectra of Iron (Hydr)Oxides 782
Mössbauer Spectra of Fired Clay Minerals 783
References 786
12.2 Identification and Quantitative Analysis of Clay Minerals 788
Identification Techniques 789
Sample Size 789
Clay Mineral Separation 789
Sample Preparation 791
Pure vs. Mixed-Layer Clay Minerals 792
Identification of Pure Clay Minerals 793
General Rules 793
Serpentine–kaolin Group 794
Talc-pyrophyllite Group 795
Smectite Group 795
Vermiculite Group 796
Illite Group 797
Chlorite Group 798
Sepiolite and Palygorskite Group 799
Identification of Mixed-Layer Clay Minerals 799
Peak Position Approach 799
Peak Broadening Approach 801
Expert Systems 802
Integrated Approach: Computer Modelling 802
Quantitative Analysis 803
Bulk Rock Quantitative Mineral Analysis 803
Sample Preparation 803
Data Collection, Processing, and Selection of Standards 804
Quantitative Mineral Analysis of Clay Fraction 805
Sample Preparation 805
Data Processing 806
References 806
12.3 X-ray Absorption Spectroscopy 812
Synchrotron-Based Techniques 813
X-ray Absorption and Scattering Processes 814
XAFS Data Analysis 819
Pre-Edge XAFS Spectroscopy 822
X-ray Near-Edge Spectroscopy (XANES or NEXAFS) 824
Powder EXAFS Spectroscopy 825
Polarised EXAFS Spectroscopy 829
XAFS Studies on Smectite Structure 835
Structural Refinement by P-EXAFS 835
Dioctahedral vs. Trioctahedral Structural Types 836
Tetrahedral Cation Distributions in Smectites 837
EXAFS Spectroscopy 837
Pre-Edge Spectroscopy 838
XANES Spectroscopy 840
Octahedral Cation Distributions and Isomorphous Substitutions in Smectites 841
Ni Bearing Layer Silicates and Minerals 842
Ni Substitution in Montmorillonite Using the Hofmann–Klemen Effect 843
Octahedral Cation Distribution in Fe-rich Layer Silicates 844
Octahedral Cation Distributions in Fe-poor Smectites 845
Orientation of Intercalated Organic Molecules 847
Spatial Resolution with Microprobe XAFS 851
XAFS Studies of Reactivity of Clays and Clay Minerals 852
Exchange/Sorption Reactions at the Smectite–Water Interface 852
Mineral Neoformation Reactions: Smectites as Nucleation Templates 859
Redox Reactions (Abiotic and Biotic) of Clays and Clay Minerals 861
P-EXAFS Study of Reduced Nontronite Structure 861
Redox Coupling between Octahedral Fe in Smectites and Sorbed TPB 862
Cr(VI) and Cr(III) Redox Reactions at Mineral Surfaces 863
Redox Reactions at Oxide and Organic Surfaces 863
XAFS Studies of Other Clay Minerals 864
Other Layer Silicates 864
Oxides and Oxyhydroxides 865
Future Outlook and Concluding Remarks 867
References 868
12.4 X-ray Photoelectron Spectroscopy 888
Principles of X-Ray Photoelectron Spectroscopy 889
Experimental Techniques 890
Instrumentation and Sample Handling 890
Quantitative Analysis 892
Chemical Information 893
Applications 896
References 899
12.5 Small-Angle Scattering Techniques 902
Principles 903
Scattering Length and Particle Scattering Length Contrast 903
Neutron Scattering 904
X-ray Scattering 904
Light Scattering 904
Quantitative Definitions of the Interference Function, P(q) 905
Dilute Suspension of Homogeneous Particles without any Interactions 905
Properties of the Shape Function i(q) 905
Particle Size Distribution 907
Heterogeneous Particles 907
Interacting Identical Particles 907
Special Problems for Clay Minerals 908
Definitions 908
SAS by Clay Minerals 909
Initial Hydration Stages and Osmotic Transition 909
SAS Analysis by Fourier Transform of Intensity 909
Geometrical Simulation of SAS 910
Anomalous Small Angle X-ray Scattering 913
Gel Structure and Sol–Gel Transition 914
Gel Structure in Natural Smectite Dispersions 914
Comparing Montmorillonite with Laponite 915
SANS Studies under Shear 917
Small-angle Light Scattering and Dynamic Light Scattering 918
SALS 918
DLS 919
SANS 920
Modelling Sol–Gel Transition in Laponite Dispersions 921
Dispersions in Organic Solvents 924
Application of SAS to Pillared Clays and Clay-Polymer Nanocomposites 925
Structure of Pillared Clay Minerals and Organo-Clays 925
Clay-polymer Nanocomposites 926
Conclusions 926
SAXS 926
SANS 926
SALS 927
References 927
12.6 Fourier Transform Infrared Spectroscopy 932
Principle and Methods 932
Mineralogical Applications 933
Crystallo-Chemical Applications 933
The Octahedral Environment 934
The Tetrahedral Environment 935
Interlayer Cations 936
Adsorption Phenomena 937
Clay–Water Interactions 937
Clay–Organic Interactions 937
Conclusions 938
References 938
12.7 Nuclear Magnetic Resonance Spectroscopy 942
NMR Spectroscopy of Clay Minerals 944
Structural Characterization 944
Cation Coordination 944
Crystallographic Sites 945
Cation Distribution 946
Adsorption Phenomena 948
Clay–Water Interactions 948
Pillared Clays 950
Clay–Organic Interactions 950
Adsorption by 2:1 Clay Minerals 950
Intercalation of Kaolin Minerals 951
Reactivity of Clay Minerals 953
Alkaline Activation of Kaolinites 953
Heterogeneous Catalysis 954
Grafting of Organic Species 954
Concluding Remarks 957
References 957
12.8 Transmission Electron Microscopy 962
TEM Techniques 963
Formation of Images 963
Principles 963
Wave Transfer in the Microscope 964
Transfer in the Real Microscope 966
Optical Settings of the Illumination Stage 966
Optical Settings of the Objective Stage 967
High Resolution Imaging 967
Energy Dispersive X-Ray Fluorescence (EDXRF) 968
Chemical Analysis by EDXRF 968
Calibration for Quantitative Chemical Analyses of Clay Minerals 969
Data Treatment and Interpretation 970
Preparation Techniques 970
Agar Coating 970
Water Potential Control 971
C. Resin Embedding 971
Ultra Thin Sectioning 972
Characterization of Clay Phases 973
Morphological Criteria and Crystal Size Measurement 973
Structural Criteria and Lattice Parameter Calculation 973
Crystalline Versus Amorphous 973
Ordered Versus Disordered Stacking Orientation in the (a, b) Plane 973
Regular Versus Random Periodicity along the Stacking Direction 974
Chemical Criteria and Structural Formulae 974
Derivation of Structural Formulae 974
Representation of Chemical Compositions 975
Characterization of Clay Material at Different States 975
Gel State: Highly Hydrated Smectites 975
Paste State: Pillared Clays, Organo-Clays, Mixed-Layer Clay Minerals 976
Pillared Clays 976
Organo-Clays 976
Mixed-Layer Clay Minerals 976
Dry State: Strongly Indurated Materials Bricks of Consolidated Clay
Image Analysis 977
Morphometry 977
Measuring Size 978
Measuring Shape 978
Quantitative Analysis 978
Clays in Pedogenetic Alteration 978
Clays in Diagenetic Alteration 980
References 981
12.9 Surface Area and Porosity 988
The Specific Surface Area of Clay Minerals 988
Swelling Clay Minerals 992
Adsorbates that Induce Swelling 993
Adsorbates that do not Induce Swelling 997
References 998
12.10 Cation and Anion Exchange 1002
Ion Exchange Reactions 1002
A. Cation Exchange Equilibria 1002
B. Selectivity 1007
C. Hysteresis 1008
D. Heavy Metal Ion Adsorption 1009
E. Anion Exchange 1010
Definition of Cec and Factors Influencing its Measurement 1011
Origin of CEC 1012
CEC Measurements 1013
A. Classical Methods 1013
B. Influence of Exchangeable and Index Cations 1014
C. Influence of pH 1014
Analytical Techniques 1014
A. Exchange with Protons 1016
B. Exchange with Organic Cations 1016
C. Exchange with Ammonium Ions 1016
D. Exchange with Alkali or Alkaline-Earth Cations 1017
E. Exchange with Transition Metal Ions or Organo-Metal Complexes 1017
Other Techniques 1017
Conclusions 1018
References 1018
12.11 Thermal Analysis 1026
Background and Development 1026
Temperature-Controlled (Conventional) Thermal Analysis 1028
Sample-Controlled Thermal Analysis 1031
Application of Thermal Analysis to Clays 1033
Analytical Aspects 1033
Preparative Aspects 1036
Kinetic Aspects 1037
References 1039
13 Some Other Materials Related to Clays 1042
Reference 1042
13.1 Layered Double Hydroxides 1044
Definitions 1044
Natural Occurrence 1045
Synthetic LDH 1047
Chemical Composition of the Layers 1047
M2+/M3+ Ratio Variation 1047
LDH with Variable M2+/M3+ Ratios 1047
LDH with Fixed M2+/M3+ Ratios 1049
Interlayer Anion Composition 1049
Synthesis 1050
Coprecipitation 1050
The Urea Method 1051
Induced Hydrolysis 1052
Reconstruction 1052
Sol-Gel Technique 1053
Hydrothermal, Microwave, and Ultrasound Treatments 1054
Anion-Exchange Reactions 1054
Synthesis of Polyoxometallate-LDH 1057
Synthesis of Organo-LDH 1058
Synthesis of LDH-Based Nanocomposites 1059
LDH with Intercalated Nanoparticles 1060
Grafting Reactions 1061
Structure 1061
General 1061
Cation and Anion Ordering 1062
Stacking Phenomena 1063
Staging 1063
Random Stacking 1063
Guest–Host Interactions 1064
Analytical Methods 1066
XRD 1066
Neutron Diffraction 1066
XAS 1067
Raman and FTIR 1068
Solid-State NMR 1068
57Fe Mössbauer Spectroscopy 1069
Computer Modeling 1069
Morphology 1070
Size and Shape 1070
Specific Surface Area and Porosity 1071
Fundamental Properties 1072
Chemical Stability 1072
Thermal Stability 1073
Effect of Interlayer Anions 1075
Calcination/Hydration Cycles and Reconstruction 1075
Layered Double Oxides and Pre-spinel Phases 1078
Surface and Colloidal Properties 1079
Surface Characterization 1079
Surface Modification 1080
Colloidal Dispersions and Delamination 1080
Surface Properties of Calcined Materials 1081
Industrial and Environmental Applications: Conventional and Novel 1081
Catalytic Applications 1081
Medical Applications 1084
Additives for Polymers 1085
Environmental Applications 1086
Adsorption of Pollutants 1086
Waste Barriers 1088
Future Developments 1088
Drug Delivery and Controlled-Release Formulations 1088
Biosensors, Biomimetic Catalysts, and Biological Reactions 1089
Electrochemical Applications 1090
Novel Functional Materials 1092
References 1093
13.2 Parallels and Distinctions between Clay Minerals and Zeolites 1120
Smectites and Zeolites: Similarities 1120
Smectites and Zeolites: Distinctions 1121
Crystal Structural Transitions 1122
Dehydration Phenomena 1128
Summary and Conclusions 1133
References 1134
13.3 Cement Hydrates 1136
Portland Cement and its Hydration 1136
Structure and Surface Properties of Cement Hydrates 1138
The Meso- and Micro-Structure of CSH 1141
CSH and Smectites 1142
Cohesion vs. Swelling 1144
Summary and Conclusions 1146
References 1148
14 Genesis of Clay Minerals 1152
Geological Environments for Clay Formation 1154
Weathering 1154
Sedimentation 1161
Burial Diagenesis and Low-Grade Metamorphism 1164
Hydrothermal Alteration 1172
Origin of Clay Deposits of Economic Interest 1175
Kaolins 1175
Bentonite 1176
Palygorskite and Sepiolite 1177
Summary 1177
References 1177
15 History of Clay Science: A Young Discipline 1186
Development of Clay Science 1186
Early Studies 1186
XRD: An Essential Tool for Clay Mineral Research 1188
Other Useful Tools for Clay Mineral Research 1188
Importance of Commercial Bentonite Production 1189
Clay Research and Applications 1189
Bleaching Earth 1189
Clays as Catalysts 1189
Clays in Engineering 1190
Organoclays 1190
Clay Research after World War II 1190
Names, First Locality, and Structural Identification 1191
History of Clay Meetings 1195
Definition of ’Clay Scientist’ 1196
References 1198
16 Teaching Clay Science: A Great Perspective 1206
Teaching Clay Science in the USA 1208
Teaching Clay Science at the University Level 1210
Teaching Practices 1210
Assessment 1212
Clay Science in the Public Schools 1213
Concluding Comments on the Scene in the USA and Other Industrialized Nations 1213
Teaching Clay Science in Germany and Other European Countries 1215
Teaching Clay Science in New Zealand and Australia 1216
Conclusions 1217
References 1217
Index 1220
Chapter 1 General Introduction: Clays, Clay Minerals, and Clay Science
a CRMD, CNRS-Université d’Orléans, F-45071 Orléans Cedex 2, France
b Institut für Anorganische Chemie, Universität Kiel, D-24118 Kiel, Germany
Abstract
Publisher Summary
This chapter attracts the attention of clay scientists in academe and industry as well as in politics (as research needs funding), and focuses on the importance of clay science to society and the quality of life. The economic benefits seem evident because clays are abundant, widespread, and inexpensive compared with other raw materials. The chapter discusses the industrial and environmental importance of clays and clay minerals. The great variety of physical, chemical, and thermal treatments that may be used to modify clays and clay minerals provide unlimited scope for future applications, particularly in terms of protecting the environment. Because of the multidisciplinary nature of clay science, its teaching is another challenging task. By learning about the mineralogical, physico-chemical, and industrial aspects of clay science, students would not only gain an appreciation of the “scientific method” and the physical environment but also find suitable employment and a fulfilling career.
The authors believe that clays and clay minerals, either as such or after modification, will be recognized as the materials of the 21st century because they are abundant, inexpensive, and environment friendly. With that in view, this Handbook of Clay Science has assembled core information on the varied and diverse aspects that make up the discipline of clay science, ranging from the fundamental structure and surface properties of clays and clay minerals to their industrial and environmental applications.
Clay has been known to, and used by, humans since antiquity. Indeed, clay has been implicated in the prebiotic synthesis of biomolecules, and the very origins of life on earth. Clay has also become indispensable to modern living. It is the material of many kinds of ceramics, such as porcelain, bricks, tiles, and sanitary ware as well as an essential constituent of plastics, paints, paper, rubber, and cosmetics. Clay is non-polluting and can be used as a depolluting agent. Of great importance for the near future is the potential of some clays to be dispersed as nanometer-size unit particles in a polymer phase, forming novel nanocomposite materials with superior thermo-mechanical properties. The diversity of structures and properties of clays, and their wide-ranging applications, make it difficult to compile a comprehensive reference text on clay science.
1.1 Aim and Scope
If the general knowledge and usage of clay have ancient roots, the scientific study of clay (i.e., ‘clay science’) is a relatively recent discipline, dating back only to the mid-1930s, following on the emergence and general acceptance of the ‘clay mineral concept’. According to this concept, clays are essentially composed of micro-crystalline particles of a small group of minerals, referred to as the clay minerals (Grim, 1968). Since then, clay science or ‘argillology’ (Konta, 2000) has become an autonomous, multi-faceted discipline.
Since people who work with clay come from diverse backgrounds and have diverse interests, there are probably as many concepts and views of clay as there are clay mineral species. It is not surprising, therefore, that clay scientists have varied trainings, including geology, mineralogy, chemistry, physics, and biology, and hold different perspectives. The multi-disciplinary nature of clay science is indicated by the scope, contents, and multi-authorship of this handbook. It is also reflected in the wide range and variety of scientific journals where papers on clays and clay minerals are published. At the same time, individuals or groups who investigate and use clay—whether they be in academe or industry—often fail to realize that they share a common interest, or worse, are ignorant of one another's existence. Similarly, information about clay is dispersed in many scientific conferences and symposia whose themes (e.g., nanotechnology, rheology, and heterogeneous catalysis) often make no reference to the experimental material used. Indeed, the word ‘clay’ in many publications is often subsumed into such terms as ‘microporous solid’ or ‘layered material’. This is probably because in the mind of many people, clay is associated with soil (dirt) and mud. By the same token, clay science is not generally considered to be intellectually challenging. If clay science features at all in the syllabus or curriculum of a university degree course, the focus is usually on the mineralogy of clay, while its colloidal and physico-chemical aspects are glanced over, if not ignored. The teaching of clay science also varies from school to school within a given country, and from one country to another.
The first two textbooks by Grim, Clay Mineralogy and Applied Clay Mineralogy, were published some 4–5 decades ago (Grim, 1953, 1962, 1968). Since then a great deal of information on clays and clay minerals has accumulated. Also, many advanced analytical and instrumental techniques have been developed as well as novel industrial and environmental applications. Yet, no general reference text on clay science in the English language has been published to date, although a number of books on particular aspects are available (e.g., Weaver and Pollard, 1973; Farmer, 1974; Theng, 1974, 1979; van Olphen, 1977; Brindley and Brown, 1980; Chamley, 1989; Wilson, 1994; Velde, 1995; Moore and Reynolds, 1997).
The Handbook of Clay Science aims to provide up-to-date information on the fundamental structural and surface properties of clay minerals, their industrial and environmental applications as well as analytical techniques, and the teaching and history of clay science. The book is intended to be a critical review and not just a compilation of the published literature. To our knowledge, this holistic multi-disciplinary approach does not exist in any other clay book. Here, we describe some generally held concepts and working definitions of clay and clay mineral that might be acceptable to most disciplines and practitioners of clay science.
The structures of clays and clay minerals together with their surface-chemical properties are summarized in Chapters 2 and 3. Synthetic clay minerals and clay purification are described in Chapter 4, while Chapter 5 deals with the colloid chemistry of clays, and Chapter 6 with their mechanical properties. Chapter 7 describes modifications of clays and clay minerals by acid activation (Chapter 7.1), thermal treatment (Chapter 7.2), and pillaring (Chapter 7.5), and has subchapters on the clay-organic interaction (Chapter 7.3), and the possible involvement of clay in the origins of life (Chapter 7.4). The properties and behaviour of iron in clay minerals are discussed in Chapter 8, while Chapter 9 reviews the role of clays in biomineralization. Chapter 10 deals with clays in industry with subchapters on the conventional applications of clays (Chapter 10.1), catalysis by clay minerals (Chapter 10.2), and the formation and properties of clay-polymer nanocomposites (Chapter 10.3). The role of clays in environmental and human health protection is discussed in Chapter 11 with six subchapters covering a wide range of topics from pollution control to clays as drugs. The eleven subchapters of Chapter 12 give a critical assessment of spectroscopic and analytical techniques commonly used in clay studies. The handbook also contains in subchapters of Chapter 13, reviews on layered double hydroxides (LDH) (Chapter 13.1), zeolites (Chapter 13.2), and cement hydrates (Chapter 13.3) because these materials are related to smectite clays in structure and certain properties. Clay mineral formation and the genesis of the principal clay deposits are described in Chapter 14, while the last two chapters are concerned with the history (Chapter 15), and teaching (Chapter 16) of clay science.
This handbook will therefore provide a point of first entry into the clay science literature for research scientists, university teachers, postgraduate students, industrial chemists as well as people in agriculture, environmental engineering, industry, and waste disposal, who need to know about clays and clay minerals. This book will also be useful to commercial users of clays.
1.2 Clay
There is, as yet, no uniform nomenclature for clay and clay material. Nonetheless, we do not seek a consensus1 about the meaning of the terms ‘clay’, ‘clays’, and ‘clay minerals’ (Table 1.1). Indeed, the quest for a unifying terminology that is acceptable to all disciplines, users, and producers would be a fruitless exercise (R.A. Kühnel, personal communication). Rather, here we aim to highlight the common meaning of these terms, and the impact of these materials on our actual daily life together with their potential for the ever-growing number of practical applications (Kühnel, 1990; Murray, 1999).
Table 1.1 Current names of clays
aSee Chapter 14 for more details.
Georgius Agricola (1494–1555), the founder of geology, was apparently the first to have formalized a definition of clay (Guggenheim and Martin, 1995). The latest effort in this direction was made nearly five centuries later by the...
| Erscheint lt. Verlag | 14.9.2011 |
|---|---|
| Sprache | englisch |
| Themenwelt | Naturwissenschaften ► Chemie |
| Naturwissenschaften ► Geowissenschaften ► Geologie | |
| Naturwissenschaften ► Geowissenschaften ► Mineralogie / Paläontologie | |
| Technik ► Maschinenbau | |
| Technik ► Umwelttechnik / Biotechnologie | |
| ISBN-10 | 0-08-045763-0 / 0080457630 |
| ISBN-13 | 978-0-08-045763-5 / 9780080457635 |
| Haben Sie eine Frage zum Produkt? |
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