Environmental Surfaces and Interfaces from the Nanoscale to the Global Scale

An advanced exploration ofwater-rock interactions

Based on the author's fifteen years of teaching and tried-and-tested experiences in the classroom, here is a comprehensive exploration of water-rock interactions. Environmental Surfaces and Interfaces from the Nanoscale to the Global Scale covers aspects ranging from the theory of charged particle surfaces to how minerals grow and dissolve to new frontiers in W-R interactions such as nanoparticles, geomicrobiology, and climate change.

Providing basic conceptual understanding along with more complex subject matter, Professor Patricia Maurice encourages students to look beyond the text to ongoing research in the field. Designed to engage the learner, the book features:

• Numerous case studies to contextualize concepts
• Practice and thought questions at the end of each chapter
• Broad coverage from basic theory to cutting-edge topics such as nanotechnology
• Both basic and applied science

This text goes beyond W-R interactions to touch on a broad range of environmental disciplines. While written for advanced undergraduate and graduate students primarily in geochemistry and soil chemistry, Environmental Surfaces and Interfaces from the Nanoscale to the Global Scale will serve the needs of such diverse fields as environmental engineering, hydrogeology, physics, biology, and environmental chemistry.

Preface xv

Constants and Units xvii

Periodic Table of the Elements

1 Some Fundamental Chemical Thermodynamic and Kinetic Concepts 1

Concentration Units 1

Thermodyamic Versus Kinetic Approaches 2

Introductory Thermodynamics 3

Gibbs Energy 4

Chemical Potential and Activity 4

Equilibrium Constants 5

Calculating the Equilibrium Constant from Gibbs Energy Changes 6

Temperature Effects on K_eq 8

Calculating Activities 9

Saturation Indices (SIs) 12

Carbonate Equilibria in Open or Closed Systems 13

Calcite Equilibria in a System Open to Atmospheric Carbon Dioxide 14

Redox Reactions 17

Metal Speciation Diagrams 19

A Brief Introduction to Kinetics 20

Overall Versus Elementary Reactions 20

Molecularity and Reaction Order 21

Transition State Theory and the Arrhenius Equation 24

Michaelis-Menten Kinetics 25

The Elovich Equation for Chemisorption Kinetics 26

Simultaneous Versus Sequential Reaction Sequences 27

Transport Versus Surface Control of Mineral Growth and Dissolution Rates 28

Rate Laws for Surface-Controlled Mineral Growth and Dissolution 30

Equilibration Time in Porous Media 31

Questions for Further Thought 31

Further Reading 34

2 The Hydrologic Cycle as Context for Environmental Surfaces and Interfaces 35

The Structure and Fundamental Properties of Water 35

The Chemical Composition of the Earth 37

The Critical Zone 38

The Hydrologic Cycle 38

Oceans 39

Atmosphere 40

Underground water 43

Soils and Soil Water 44

Groundwater 45

Surface Waters: Focus on Rivers 52

Stream Load 52

Gibbs Plots 54

The Hyporheic Zone 56

The OTIS Model and Solute Transport in Streams 56

Particle Transport and Sedimentation 57

Water Budgets and Chemical Fluxes in Terrestrial Ecosystems 59

Questions for Further Thought 62

Further Reading 66

3 Some Minerals of Special Interest to Environmental Surface Chemistry 67

Gibbsite 67

Quartz 68

Kaolinite 69

Smectite: Example Montmorillonite 71

Fe(hydr)oxides 73

Hematite 73

Goethite 73

Lepidocrocite 76

Maghemite 77

Ferrihydrite 77

Magnetite 77

Manganese Oxides 77

Calcite 78

Feldspars 79

Zeolites 79

Questions for Further Thought 81

Further Reading 81

4 Some Key Techniques for Investigating Surfaces and Interfaces 82

A Brief Overview of Some Commonly Used Techniques 82

In-Depth Descriptions of Some Key Techniques 86

Scanning Electron Microscopy (SEM) 86

Transmission Electron Microscopy (TEM) 87

Scanning Tunneling Microscopy (STM) 90

Case Study: Imaging Parameters and High-Resolution Imaging of Hematite 91

AFM and Interfacial Forces 92

X-Ray Photoelectron Spectroscopy (XPS) 99

BET Surface Area Measurements 100

Some Synchrotron-Based Techniques 103

Microscopies for Biofilm Imaging 108

Questions for Further Thought 108

Further Reading 111

5 Surfaces and Interfaces 112

What is a Surface? What is an Interface? 112

The Challenges of Defining Surfaces and Interfaces 113

Surfaces are Complex 114

Relaxation and Reconstruction 114

Surface Sites 115

Surface Microtopography 116

Surface Free Energy 117

Water Near Surfaces 119

Dynamic Surfaces 120

Bacterial Substrates 120

Fractal Properties of Surfaces and Environmental Particles 120

Interdisciplinary Topic of Study 123

Surface Free Energy and Surface Excess 124

Surface Tension and Related Phenomena 126

Surfactants and Micelles 126

Contact Angle 127

The Young-Laplace Equation 128

Meniscus and Capillarity 128

The Gibbs Equation 130

Some Approaches to Surface and Interface Modeling 130

Case Study: Bacteria–Mineral–Gas Interactions in the Vadose Zone 132

Questions for Further Thought 133

Further Reading 135

6 The Charged Interface and Surface Complexation 136

Some Evidence for Surface Charge 136

Sources of Mineral Surface Charge 137

Points of Zero Charge 139

Case Study: The Surface Charge Properties of Kaolinitic Soils 140

Sorption Terminology 141

Cation Exchange Capacity 145

Sorption Isotherms 148

Adsorption Isotherm Equations 151

The Langmuir Isotherm Equation 151

The Freundlich Isotherm Equation 152

The Frumkin Isotherm Equation 153

The Double Layer, Gouy-Chapman Theory 153

Beyond Gouy-Chapman: Surface Complexation Models 155

Constant Capacitance Model (CCM) 161

The Diffuse Double Layer (DDL) Model 161

Triple Layer Model (TLM) 161

Charge Distribution CD/MUSIC Model 162

Model Verification and Validation 163

Case Study: Incorporating the Work Associated with Removal of Water During Adsorption into the TLM 164

DLVO Theory and Colloid Attachment in Porous Media 165

Questions for Further Thought 168

Further Reading 172

7 Sorption: Inorganic Cations and Anions 173

A Typical Sorption Experiment Design 174

Metal Cation Sorption 176

The Complexity of Cation Adsorption 179

Inorganic Anion Adsorption 183

Phosphate Adsorption 184

Nitrate Adsorption 186

Sulfate Adsorption 186

Carbonate Sorption 186

Importance of Redox State and Valence to Inorganic Ion Adsorption 187

Chromium 187

Neptunium 188

Uranium 188

Selenium 188

Case Study: Arsenic Speciation and Mobility 189

Questions for Further Thought 192

Further Reading 193

8 Sorption: Organic Compounds 194

A Brief Introduction to Organic Chemistry 195

Some Organic Compounds of Interest in Environmental Surface Chemistry 200

Polymers 200

Organic Surfactants, Including Fatty Acids 200

Humic Substances 201

Polycyclic Aromatic Hydrocarbons (PAHs) 202

Substituted Nitrobenzenes (SNBs) 204

Volatile Organic Compounds (VOCs) 205

Sorption of Simple Organic Ligands, Surfactants, and Natural Organic Matter 205

Adsorption of Simple Organic Ligands 205

Adsorption of Anionic Surfactants, Fatty Acids 207

Sorption of Cationic Surfactants 208

Sorption of Phospholipid Surfactants: Biomedical Implications 209

Adsorption of Humic And Fulvic Acids (NOM) 210

Metal–Ligand Coadsorption: Ternary Surface Complexes 214

Sorption of Some Organic Pollutants 215

Vapor Pressure, Solubility, and Density 215

The Octanol-Water Partition Constant, K_ow 218

Organic Fuel and Solvent Leaks: Volatilization, Solubility, Density, and K_ow 219

The Hammett Constant σ for Substituted Aromatic Acids Based on the Benzene Ring 220

Case Study: Sorption of SNBs 221

Molecular Dynamics (MD) Modeling of Atrazine Absorption 223

The K d Approach to Hydrophobic Organic Compound Transport in Porous Media 224

Activated Carbon and Sorption of VOCs 226

Questions for Further Thought 227

Further Reading 230

9 Mineral Nucleation and Growth 231

Saturation State and Mineral Nucleation: An Example of the Confluence of Thermodynamics and Kinetics 231

Hydroxypyromorphite Nucleation 233

Heterogeneous Nucleation and Epitaxial Growth 233

From Nucleation to Growth 236

Ostwald Ripening 236

Transport and Surface Controlled Growth 236

The Special Importance of Kink Sites 237

BCF Theory 238

Growth Mode and Driving Force 240

Case Study: Calcite Birth and Spread versus Spiral Growth: BCF Theory 241

Rates of Step Advancement 242

Impurities and Growth at Steps 245

Monte Carlo Simulations of Crystal Growth 246

Biomineralization 247

Carbonate Precipitation in the Marine Environment 249

Questions for Further Thought 251

Further Reading 252

10 Mineral Weathering and Dissolution 253

Chemical, Physical, and Biological Weathering 253

Thermodynamics of Mineral Weathering 256

Kinetics of Mineral Dissolution 260

Etch Pit Formation 261

Oxalate Promoted Dissolution of Hematite 263

Comparison of Laboratory- and Field-Based Dissolution Rates 264

Reactive Surface Area and Feldspar Dissolution 266

Rainfall and Weathering: An Example from the Hawaiian Islands 269

Case Study: Weathering in the Antarctic Dry Valleys 270

Reactors for Dissolution Experiments 273

The Use of Radiogenic Isotopes in Weathering Studies 276

Questions for Further Thought 276

Further Reading 279

11 Plants as Environmental Surfaces 280

Ecohydrology and Soil Moisture Balance 280

Some Notes on Angiosperm Physiology 282

The Nutrient Needs of Plants 282

Effects of Plants on Mineral Dissolution and Weathering 284

Modes of Plant Elemental Cycling 287

Plants and Biomineralization: Phytoliths 287

Plants and Formations in Limestone Caves 289

Phytoremediation as an Example of Plant-Mineral-Contaminant Interactions 291

Case Study: Phytoremediation of Atrazine 293

Questions for Further Thought 294

Further Reading 295

12 Microorganisms As Environmental Surfaces 296

How Microorganisms “make a Living” 298

Metabolic Pathways 298

Microbial Redox Reactions and Michaelis-Menten Kinetics 303

Microbial Temperature Ranges and Extremophiles 305

Microbial Growth Curves 306

Bacterial Groups 307

Bacterial Cell Walls 307

Bacterial Adhesion and Biofilms 309

Bacterial–Metal Interactions 312

Bacterial-Promoted Mineral Dissolution 313

Dissolution of Fe(III)(hydr)oxides by DIRB 313

Dissimilatory Metal-Reducing Bacteria 315

Microbial Effects on Carbonate Dissolution 315

The Importance of Field-Based Studies 317

Case Study: The In Situ Microcosm Approach 318

Coupling In Situ Microcosms with Community Analysis 318

Siderophores 320

Microbial Biomineralization 322

Carbonate Precipitation 322

Fe(III)(hydr)oxide Precipitaton: BIOS 323

Banded Iron Formations (BIF) 324

(Alumino)silicate Precipitation 326

Case Study: Bioremediation of U at the Oak Ridge National Laboratory Site 327

Microbial Fuel Cells 329

Questions for Further Thought 332

Further Reading 333

13 Environmental Nanoscience and Nanotechnology 335

What is a Nanoparticle? 335

Nanoparticle Occurrence and Distribution 337

What Makes a Nanoparticle Different? 339

Nanoparticle Surface Area, Stability, and Reactivity 340

Nanoparticles Have a Different Electronic Structure 340

How Electronic Structure Influences Nanoparticle Behavior 342

Nanoparticle Disorder and Defect Structures 343

Ferrihydrite Size, Structure, and Stability 343

Effects of pH and Adsorbed Ions on Nanoparticle Stabilities 344

Case Study: Fe(hydr)oxide Size and Stability 345

Secondary Growth of Nanoparticles 346

Self-Assembly and Templating 348

Nanoparticle Transport in Porous Media 348

The Emergence of Nanotechnology 350

Potential Environmental Effects of Engineered Nanoparticles 351

Questions for Further Thought 353

Further Reading 354

14 The Big Picture: Interface Processes and the Environment 356

Reactive Transport Models for Metals and Radionuclides in Porous Media 356

The K d Approach Encounters Difficulties for Metals and Radionuclides 356

Comparison of the K d versus Surface Complexation Modeling Approaches 357

Acid Rain Effects on Chemical Weathering 358

What Makes Rainfall Acidic? 359

Effects of Acid Rain 360

Acid Rain and Chemical Weathering 360

The Small Watershed Approach 362

NETPATH and PHREEQC 362

The Clean Air Act and Acid Rain Over Time 363

Acid Mine Drainage 364

The Environmental Problem 365

Nanoparticles and AMD 365

Hydrobiogeochemical and Photoreductive Processes 365

Biofilms and AMD 367

Potential Remediation Strategies 369

Environmental Particles and Climate Change 369

Climate Forcing and Feedbacks 370

Volcanoes and Climate 373

CO₂ and Weathering 374

Modeling the C Cycle Over Geologic Time 376

Scaling Phenomena: Integrating Observations from the Atomic to the Watershed to the Global Scale 378

The Concept of the Macroscope 378

Embedded Sensor Network Systems 379

Sensors for Surface and Interface Phenomena 380

New Opportunities: New Challenges 380

Questions for Further Thought 381

Further Readings 383

Glossary of Terms 385

References 405

Index 437

Patricia Maurice is Professor in the Department of Civil Engineering and Geological Sciences at the University of Notre Dame. She is on the editorial panel of Environmental Engineering Science, and sits on the Board of Directors for the Consortium of Universities for the Advancement of Hydrological Sciences.