Environmental Soil and Water Chemistry Principles and Applications

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  • V. P. EVANGELOU

    SOIL andWATER

  • ENVIRONMENTAL SOIL AND WATER CHEMISTRY

  • ENVIRONMENTAL SOIL AND WATER CHEMISTRY PRINCIPLES AND APPLICATIONS

    v. P. EVANGELOU University of Kentucky Lexington, Kentucky

    A Wiley-Interscience Publication JOHN WILEY & SONS, INC. New York Chichester Weinheim Brisbane Singapore Toronto

  • This book is printed on acid-free paper. 9 Copyright 1998 by John Wiley & Sons, Inc. All rights reserved.

    Published simultaneously in Canada.

    No part of this pUblication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, scanning or otherwise, except as permit-ted under Sections 107 or 108 of the 1976 United States Copyright Act, without either the prior written permission of the Publisher, or authorization through payment of the appropriate per-copy fee to the Copyright Clearance Center, 222 Rosewood Drive, Danvers, MA 01923, (978) 750-8400, fax (978) 750-4744. Requests to the Publisher for permission should be addressed to the Permissions Department, John Wiley & Sons, Inc., 605 Third Avenue, New York, NY 10158-0012, (212) 850-6011, fax (212) 850-6008, E-Mail: PERMREQ@WILEY.COM.

    Library of Congress Cataloging-in-Publication Data Evangelou, V. P.

    Environmental soil and water chemistry: principles and applications I Bill Evangelou. p. cm.

    Includes bibliographical references and index. ISBN 0-471-16515-8 (cloth: alk. paper)

    1. Soil pollution. 2. Soil chemistry. 3. Water-Pollution. 4. Water chemistry. I. Title. TD878.E93 1998 628.5-dc21 98-13433

    CIP

  • To my late brother, P. Evangelou, M.D., who taught me how to read and write. His gift is passed on!

    Thank you to my Wife Shelly, daughter Julia, and son Peter, with love

    Do you feel the need to read because you understand or do you feel the need to understand and therefore you read?

  • I

    Contents

    Preface

    About the Author

    PRINCIPLES

    WATER CHEMISTRY AND MINERAL SOLUBILITY

    1 Physical Chemistry of Water and Some of Its Constituents 1.1 Elements of Nature 3

    1.1.1 Light Metals [Groups 1, 2, and Aluminum (AI)] 5 1.1.2 Heavy Metals (Transition Metals) 6 1.1.3 Nonmetals or Metalloids 6

    1.2 Chemical Bonding 6 1.3 Review of Chemical Units 12 1.4 Basic Information About Water Chemistry 16

    1.4.1 Physical States and Properties of Water 17 1.4.2 Effects of Temperature, Pressure, and

    Dissolved Salts 20 1.4.3 Hydration 21

    1.5 Chemical Properties of Water 22

    xvii

    xix

    1

    3

    3

    1.6 Bronsted-Lowry and Lewis Definitions of Acids and Bases 23

    2

    1.6.1 Weak Monoprotic Acids 24 1.6.2 Weak Polyprotic Acids 25 1.6.3 Titration Curve 27 1.6.4 Environmental Water Buffers 29 1.6.5 Open and Closed Systems 32 Acid-Base Chemistry Problems 34

    Problems and Questions 42

    SolutionlMineral-Salt Chemistry 2.1 Introduction 45

    2.1.1 Mineral Solubility 48 2.1.2 Single-Ion Activity Coefficient 51 2.1.3 Ion Pair or Complex Effects 53

    45

    vii

  • viii CONTENTS

    Iteration Example 62 2.1.4 Role of Hydroxide on Metal Solubility 65

    Special Note 71 2.1.5 Solubility Diagrams 78

    2.2 Specific Conductance 80 Example 82

    2.3 Acidity-Alkalinity 82 2.3.1 Alkalinity Speciation 83 2.3.2 Neutralization Potential 87 2.3.3 Alkalinity Contribution by CaC03 88

    2.4 Chelates 91 Problems and Questions 98

    IT SOIL MINERALS AND SURFACE CHEMICAL PROPERTIES 100

    3 Soil Minerals and Their Surface Properties 3.1 Composition and Structure of Soil Minerals 100 3.2 Aluminosilicate Minerals 102

    Soil Mineral Terms and Definitions 116 3.3 Metal-Oxides 131 3.4 Soil Organic Matter 131

    3.4.1 Humic Substances 135 3.4.2 Reaction Among Humic Substances, Clays,

    and Metals 137 3.4.3 Mechanisms of Complex Formation 140

    3.5 Clay Mineral Surface Charge 141 3.5.1 Permanent Structural Charge 141 3.5.2 Variable Charge 146 3.5.3 Mixtures of Constant and Variably

    Charged Minerals 149 3.5.4 Relevant Soil Charge Components 150

    3.6 Soil-Mineral Titrations 154 3.6.1 Conductimetric Titration 154 3.6.2 Potentiometric Titration 156 3.6.3 Soil Acidity 160

    3.7 Soil and Soil Solution Components 163 3.8 Role of Soil-Minerals in Controlling Water Chemistry 164 Problems and Questions 164

    4 Sorption and Exchange Reactions 4.1 Sorption Processes 167

    4.1.1 Surface Functional Groups 169 4.2 Adsorption-Sorption Models 178

    4.2.1 Freundlich Equilibrium Approach 179

    100

    167

  • CONTENTS ix

    ill

    4.2.2 Langmuir Equilibrium Approach 183 4.2.3 Surface Complexation Models 186 Adsorption on a Surface Fraction Basis 188

    4.3 Exchange Reactions 191 4.3.1 Homovalent Cation Exchange 191 Relationship Between CRCa and ExCa 194 Nonpreference Homovalent Isotherms 196 4.3.2 Heterovalent Cation Exchange 196 Relationship Between SAR and ExNa 199 4.3.3 The Vanselow Equation 201 4.3.4 Relationship Between Kv and KG 205 4.3.5 Ion Preference 208 Nonpreference Heterovalent Isotherms 209 4.3.6 Adsorbed-Ion Activity Coefficients 210 Example on Adsorbed-Ion Activity Coefficients 211 4.3.7 Quantity-Intensity Relationships 213 QII Justification 215 4.3.8 Ternary Exchange Systems 216 4.3.9 Influence of Anions 219 4.3.10 Exchange Reversibility 221 4.3.11 Thermodynamic Relationships 223

    Problems and Questions 225

    ELECTROCHEMISTRY AND KINETICS

    5 Redox Chemistry 5.1 Redox 229 5.2 Redox-Driven Reactions 231

    Some Thermodynamic Relationships 232 5.3 Redox Equilibria 234

    5.3.1 Redox as Eh and the Standard Hydrogen Electrode (SHE) 235

    5.3.2 Redox as pe and the Standard Hydrogen Electrode (SHE) 236

    5.3.3 Redox as Eh in the Presence of Solid Phases 5.3.4 Redox as pe in the Presence of Solid Phases

    5.4 Stability Diagrams 244 5.5 How Do You Measure Redox? 253

    5.5.1 Redox in Soils 255 Problems and Questions 259

    6 Pyrite Oxidation Chemistry 6.1 Introduction 260 6.2 Characterization 261

    229

    229

    241 243

    260

  • x

    7

    6.3 Pyrite Oxidation Mechanisms 261 6.4 Bacterial Pyrite Oxidation 263 6.5 Electrochemistry and Galvanic Effects 264 6.6 Bacterial Oxidation of Fe2+ 265 6.7 Surface Mechanisms 265 6.8 Carbonate Role on Pyrite Oxidation 268 6.9 Mn- and Fe-Oxides 269 6.10 Prediction of Acid Drainage 269

    6.10.1 Potential Acidity 269 6.10.2 Acid-BaseAccounting 270 6.10.3 Simulated Weathering 270

    Problems and Questions 271

    Reaction Kinetics in Soil-Water Systems 7.1 Introduction 272 7.2 Rate Laws 274

    7.2.1 First-Order Rate Law 274 7.2.2 Second-Order Rate Law 276 7.2.3 Zero-Order Rate Law 277

    7.3 Application of Rate Laws 279 7.3.1 Pseudo First-Order Reactions 280 7.3.2 Reductive and Oxidative Dissolution 287 7.3.3 Oxidative Precipitation or Reductive

    Precipitation 291 7.3.4 Effect of Ionic Strength on Kinetics 294 7.3.5 Determining Reaction Rate Order 295

    7.4 Other Kinetic Models 297 7.5 Enzyme-Catalyzed Reactions (Consecutive

    Reactions) 299

    CONTENTS

    272

    7.5.1 Noncompetitive Inhibition, Michaelis-Menten Steady State 299

    Derivation of the Noncompetitive Equation 302 7.5.2 Competitive Inhibition 304 Derivation of Competitive Inhibition 306 7.5.3 Uncompetitive Inhibition 307 Derivation of Uncompetitive Inhibition 309 7.5.4 Competitive-Uncompetitive Inhibition 310 Competitive-Uncompetitive Inhibition 311

    7.6 Factors Controlling Reaction Rates 313 7.6.1 Temperature Influence 313 7.6.2 Relationships Between Kinetics and

    Thermodynamics of Exchange 317 Problems and Questions 318

  • CONTENTS

    APPLICATIONS

    IV SOIL DYNAMICS AND AGRICULTURAI,-ORGANIC CHEMICALS

    xi

    321

    323

    8 Organic Matter, Nitrogen, Phosphorus and Synthetic Organics 323 8.1 Introduction 323

    v

    8.2 Decomposition of Organic Waste 323 8.2.1 Some General Properties of Soil Organic

    Matter (SOM) 325 8.2.2 Nitrogen Mineralization-Immobilization 326 8.2.3 Ammonia Reactions in Soil-Water Systems 329 8.2.4 NH3 Volatilization 330 An Equilibrium-Based Model for Predicting Potential Ammonia Volatilization from Soil 332 8.2.5 Nitrification 334 8.2.6 Denitrification 340 8.2.7 Eutrophication 341

    8.3 Phosphorus in Soils 342 8.4 Sulfur in Soils. 344 8.5 Microbial Role in Soil Reactions 345 8.6 Synthetic Organic Chemicals 345

    8.6.1 Names of Organic Compounds-Brief Review 345 8.6.2 Persistence of Organics in Soil-Water Systems 352 8.6.3 Adsorption-Sorption of Synthetic Organics . 355

    Problems and Questions 362

    COLLOIDS AND TRANSPORT PROCESSES IN SOILS

    9 Soil Colloids and Water-Suspended Solids 9.1 Introduction 364 9.2 Factors Affecting Colloid Behavior and Importance 366

    9.2.1 Colloid Dispersion or Flocculation 367 9.2.2 Zeta Potential 373 9.2.3 Repulsive Index 374

    9.3 Flocculation and Settling Rates 383 9.4 Flocculants 389 Problems and Questions 389

    364

    364

    10 Water and Solute Transport Processes 391 10.1 Water Mobility 391 10.2 Soil Dispersion-Saturated Hydraulic Conductivity 393 10.3 Solute Mobility 397

  • xii

    10.4 Miscible Displacement 398 Problems and Questions 405

    CONTENTS

    11 The Chemistry and Management of Salt-Affected Soils and Brackish Waters 407 11.1 Introduction 407

    11.1.1 Osmotic Effect 408 11.1.2 SpecificIon Effect 408 11.1.3 Physicochemical Effect 408 Derivation of the Empirical SAR-ESP Relationship 409

    11.2 Salts and Sources 411 11.2.1 High Sodium 411 11.2.2 SAR and ESP Parameters 411 11.2.3 SAR-ESP Relationships 412 11.2.4 Adverse Effects ofNa+ in the Soil-Water

    Environ