Geochemistry of Colloid Systems : For Earth Scientists

Colloid science has been applied by soil chemists and clay mineral­ ogists for many years, and some of the most important studies on the behavior of colloids have been contributed by them. Barring a few notable exceptions, only in the last decade have geochemists applied colloid science in their research and in this period much work has been published. It seemed to the authors that it would be useful at this stage to attempt to summarize the progress made and to try to examine what colloid science has contributed and can further contribute to geo­ chemistry. This book is based partly on a course of the same title given to graduate students by one of the authors (S. Y) between 1972 and 1977 at the Department of Geology at the Hebrew University of Jerusalem. Consequently many fundamental concepts of the subject are included that will be of use to graduate students in geology, geo­ chemistry, soil science, and oceanography. So that specialists interested in certain sections may find their subjects comprehensively covered, a few topics are dealt with in more than one chapter so that readers may ignore sections not especially of interest to them. However the chapters more fully treating certain topics are cross-referenced. In such cases the subjects are treated from different viewpoints and the citations used represent these dif­ fering viewpoints.

1. What is Colloid Science?.- 2. Classification of Colloid Systems.- 2.1 Based on States of Matter.- 2.2 Based on Chemical Properties of the Components.- 3. Crystal Chemistry of Silicates.- 3.1 Island Structure.- 3.2 Chain and Ribbon Structures.- 3.3 Layer Structure.- 3.4 Three-dimensional Network.- 4. Water.- 4.1 Fine Structure of Water.- 4.2 Fine Structure of Aqueous Inorganic Salt Solutions.- 4.3 Fine Structure of Aqueous Solutions of Small Non-polar Molecules and Radicals.- 4.4 Liquid Boundary Layer.- 4.5 Aqueous Solutions of Hydrophilic Colloids.- References.- 1 Some Geologic Colloid Systems.- 1. Mineralogy of Colloids in the Sedimentary Cycle.- 1.1 Structure of the Common Clay Minerals.- 1.2 Hydrous Oxides of Aluminum and Iron.- 2. Soils and Sediments as Colloid Systems.- 2.1 Solid Fraction in Soils and Sediments.- 2.2 Water in Soils and Sediments.- 2.3 Gases in Soils and Sediments.- 2.4 Organic Matter in Soils and Sediments.- 3. Fluidized Beds.- 4. Magma as a Colloid System.- 4.1 Magmaphilic Polymeric Structures.- 4.2 Magmaphobic Colloids.- 4.3 Emulsions of Immiscible Liquids.- 4.4 Foam of Volatiles.- 5. Colloid Systems in Volcanic Eruptions.- 5.1 Lava.- 5.2 Volcanic Smokes.- 6. The Ocean as a Colloid System.- 6.1 Air-Water Interface.- 6.2 Gas Bubbles in the Ocean.- 6.3 Suspended Inorganic Solids in the Ocean.- 6.4 Organic Compounds in the Ocean.- 7. The Atmosphere as a Colloid System.- 7.1 Tropospheric Aerosols.- 7.2 Stratospheric Aerosols.- References.- 2 Physical Chemistry of Surfaces.- 1. Thermodynamics of Heterogeneous Systems.- 1.1 Thermodynamic Properties and Quantities of the Interface.- 1.2 Pressure Dependence of Chemical Potential and of Water Migration in Compacting Sediments.- 1.3 Surface Tension, the Strength of Intermolecular Forces and Cleavage of Mineral Crystals.- 1.4 Capillary Pressure.- 1.5 Contact Angle of a Liquid at a Boundary of Three Phases and the Wetting Process.- 2. Liquid Surface.- 2.1 Liquid Surface Tension.- 2.2 Evaporation.- 3. Sorption.- 3.1 Sorption of Gases and Vapors by Solids.- 3.2 Sorption by Solids from Solutions.- 3.3 Sorption onto a Liquid-Gas Interface.- 3.4 Gas Exchange Across a Gas-Liquid Interface.- 3.5 Ion Exchange.- 3.6 Sorption and Surface Tension.- 4. Electrochemistry of Heterogeneous Systems.- 4.1 Electric Double Layer at a Solid-Liquid Interface.- 4.2 Electrokinetic Phenomena.- 4.3 Theory of Electrokinetic Phenomena.- 4.4 Electric Properties of Dust Storms.- References.- 3 Formation of Aqueous Solutions and Suspensions of Hydrophobic Colloids.- 1. Condensation Process (Formation of New Phases).- 1.1 Chemistry of Aluminum in Natural Waters.- 1.2 Chemistry of Iron and Manganese in Natural Waters.- 2. Dispersion Process.- 2.1 Physical Weathering.- 2.2 Chemical Weathering.- 2.3 Detachment of Particles Caused by Rainfall.- 2.4 Peptization.- References.- 4 Surface Coatings on Rocks and Grains of Minerals.- 1. Incongruent Dissolution of Silicates.- 2. Sorption from Aqueous Solutions onto Mineral Surfaces.- 2.1 Sorption by Long-range Interactions.- 2.2 Sorption by Short-range Interactions.- 3. Alteration of Minerals by Abrasion.- 3.1 Abrasion of Silica and Silicate Minerals.- 3.2 Abrasion of Calcite.- 3.3 Abrasion pH Values of Minerals.- 4. Surface Structures of Gibbsite and Goethite.- References.- 5 Kinetic Properties of Colloid Solutions.- 1. Kinetic Properties of Particles Dispersed in Still Fluids.- 1.1 Brownian Movement.- 1.2 Diffusion.- 1.3 Sedimentation.- 2. Kinetic Properties of Particles in Flowing Fluids.- 2.1 Laminar and Turbulent Flow.- 2.2 Fluid Drag.- 2.3 Dispersion of Particles in a Turbulent System.- 2.4 Entrainment of Sediment.- References.- 6 Colloid Geochemistry of Silica.- 1. Surface Chemistry of Silica.- 1.1 Functional Groups on Silica.- 1.2 Functional Groups on Silica-Alumina.- 1.3 Opals.- 2. Silica in Aqueous Solutions.- 2.1 Polymerization and Depolymerization of Silicic Acid.- 2.2 Solubility of Silica.- 2.3 Silica Sorption by Minerals.- 2.4 Silica in Natural Waters.- References.- 7 Colloid Geochemistry of Clay Minerals.- 1. Functional Groups on Clay Minerals and Ion Exchange Reactions.- 1.1 “Broken-bond” Surfaces.- 1.2 Interlayer Space of 2:1-Type Clay Minerals.- 1.3 The Flat Oxygen and Hydroxyl Planes.- 2. Interaction Between Clay Minerals and Organic Compounds.- 2.1 Sorption of Organic Ions by Clay Minerals.- 2.2 Sorption of Organic Polar Molecules by Clay Minerals.- 2.3 Organic Reactions Catalyzed by Clay Minerals.- 3. Solubility of Clay Minerals.- 4. Environmental Effects on Clay Mineralogy.- 4.1 Origin of Primary-stage (Neoformation) Clay Minerals and Their Related Environment.- 4.2 Environmental Relationships of N + 1 Stage Clay Minerals.- References.- 8 Interaction Between Solid Particles Dispersed in Colloid Systems.- 1. Interaction Between Solid Particles Dispersed in a Gaseous Phase.- 1.1 Van Der Waals―London Forces Between Disperse Particles.- 1.2 Electrostatic Forces Between Disperse Particles.- 1.3 Effect of Adsorbed Water Monolayer on Desert Varnish.- 2. Aggregation of Particulate Matter in the Hydrosphere.- 2.1 Interactions Between Solid Particles Dispersed in a Liquid Medium.- 2.2 Stability of Aqueous Hydrophobic Colloid Solutions and Suspensions.- 2.3 Coagulation in Natural Waters.- 3. Soil Aggregates.- 3.1 Interaction Between Clay Particles.- 3.2 Interaction Between Sand Grains.- 3.3 Reactions of Humic Substances with Mineral Soil Components.- 3.4 Pore Space in Soils.- 3.5 Stability of Aqueous Soil Dispersions and the Migration of Soil Constituents.- References.- 9 Rheology of Colloid Systems.- 1. Flow Behavior of Suspensions.- 2. Rheology of Dispersions in the Hydrosphere.- 2.1 Rheology of Dilute Dispersions.- 2.2 Rheology of Concentrated Dispersions and Muds.- 3. Rheology of Sediments of Silicate Minerals.- 3.1 Wet Sediments of Sand Grains.- 3.2 Argillaceous Sediments.- 4. Viscosity of Magmas.- References.- 10 Colloid Geochemistry of Argillaceous Sediments.- 1. Microstructure of Argillaceous Sediments.- 1.1 Microstructure of Fresh Sediments.- 1.2 Microstructure of Compacted Sediments.- 2. Aging and Diagenetic Alteration of Smectites in Argillaceous Sediments.- 3. Surface Chemistry of Solutes Flow Through Argillaceous Sediments.- 3.1 Nature of Pores in Shales.- 3.2 Effect of Migrating Water on the Migration of Solutes.- 4. Diagenesis of Organic Matter and Oil Generation in Argillaceous Sediments.- 4.1 Petroleum Origin Related to Kerogen.- 4.2 Generation of Hydrocarbons.- References.- Author Index.- Mineral Index.