SOIL and WATER CHEMISTRY

Transcription

1 SOIL and WATER CHEMISTRY An Integrative Approach MICHAEL E. ESSINGTON CRC PRESS Boca Raton London New York Washington, D.C.

2 Table of Contents Chapter 1 The Soil Chemical Environment: An Overview Phases and Chemical Processes in Soil Intraphase Soil Processes Interphase Soil Processes i Elements in the Soil Environment: Their Concentrations and Important Species Units and Conversions Heterogeneity of Soil Chemical Characteristics Descriptive Statistical Properties Geostatistics Variograms Interpolation by Kriging Exercises 31 References 34 Chapter 2 Soil Minerals, Chemical Bonds Pauling's Rules Crystal Structure Silicate Classes Nesosilicates Sorosilicates Cyclosilicates Inosilicates Phyllosilicates Tectosilicates Clay Mineralogy Division 1:1 Phyllosilicate Minerals Division 2:1 Phyllosilicate Minerals Pyrophyllite Group Smectite Group Vermiculite Group Mica and Illite Groups Chlorite Group Interstratified Layer Silicates Hydrous Metal Oxides Hydrous Aluminum Oxides Hydrous Iron Oxides Hydrous Manganese Oxides Allophane and Imogolite X-Ray Diffraction Analysis Principles Clay Mineral Characterization Exercises 98 References 100

3 Chapter 3 Chemical Weathering Hydrolysis and Oxidation Balancing Chemical Reactions Mineral Stability: Primary Silicates in the Sand- and Silt-Sized Fractions Mineral Stability: Clay-Sized Fraction Ill 3.5 Weathering and Formation Characteristics of the Phyllosilicates Mica Chlorite Vermiculite Smectite General Weathering Scheme for the Phyllosilicates Exercises 125 References 127 Chapter 4 Organic Matter in Soil Determination of Soil Organic Carbon Concentrations Organic Functional Groups: A Review Nonhumic Substances Carbohydrates Nitrogen, Sulfur, and Phosphorus Compounds Lipids Lignins Humic Substances Genesis of Humic Substances Chemical and Structural Characteristics of Humic Substances Elemental Content Functional Groups and Structural Components Molecular Mass and Configuration Exercises 178 References 180 Chapter 5 Soil Water Chemistry Nature of Water Ion Hydration Electrolyte Solutions Hydrolysis of Cations Lowry-Br0nsted Acids and Bases Complex Ions and Ion Pairs Stability of Soluble Complexes The Irving and Williams Series Metal-Fulvate Interactions The Ion Association Model Ion Speciation in Soil Solution Acid Soil Solution Alkaline Soil Solution Qualitative Aspects of Ion Speciation Soil Water Sampling Methodologies In Situ Soil Water Sampling Ex Situ Soil Water Sampling 236

4 5.11 Methods of Chemical Analysis: Elemental Analysis Atomic Spectrometry Flame Atomic Absorption Spectrophotometry Atomic Emission Spectrometry Graphite Furnace Atomic Absorption Spectrophotometry Hydride Generation Atomic Absorption Spectrophotometry Inductively Coupled (Argon) Plasma Spectrometry Exercises 248 References 251 Chapter 6 Mineral Solubility.' Mineral Solubility: Basic Principles Mineralogical Controls on Ion Activities in Soil Solutions The Ion Activity Product and Relative Saturation Application of Mineral Solubility Principles: Impediments The Estimation of Standard Free Energies of Formation Metastability and the Step Rule The Deviation of K sp from K dis Poorly Crystalline and Microcrystalline Solids Solid Solutions Mineral Solubility and Solution Composition Stability Diagrams Activity Diagrams Activity Ratio Diagrams The Temperature Dependence of the Equilibrium Constant In Situ Stabilization: Observed and Predicted Transformations of Metallic Lead in Alkaline Soil Predominance Diagrams Predicting Solution Composition Exercises 305 References 308 Chapter 7 Surface Chemistry and Adsorption Reactions Surface Functional Groups and Complexes Inorganic Soil Particle Surfaces and the Source of Charge Surface Complexes The Solid-Solution Interface: A Microscopic View Surface Charge Density Points of Zero Charge The Electric Double-Layer Quantitative Description of Adsorption The Adsorption Isotherm Linear Partition Theory Adsorption Kinetics and Desorption Hysteresis Specific Retention of Metals and Ligands Ligand Effects on Metal Adsorption Organic Surface Functional Groups and Organic Molecular Retention Mechanisms Organic Surface Functional Groups Molecular Retention Mechanisms 373

5 7.7 Surface Complexation Models The Nonelectrostatic Model Electrostatic Effects on Adsorption The Constant Capacitance Model The Modified Triple Layer Model Exercises 394 References 397 Chapter 8 Cation Exchange Cation Exchange: A Beginning for Soil Chemistry Qualitative Aspects of Cation Exchange Cation Exchange Capacity and Exchange Phase Composition Exchange Phase Composition Methods of Measuring the Cation Exchange Capacity Ammonium Acetate (ph 7 or 8.2) Cation Exchange Capacity of Arid Land Soils Cation Exchange Capacity of Acid Soils Unbuffered Salt Extraction Quantitative Description of Cation Exchange Cation Exchange Selectivity Kerr Selectivity Coefficient Vanselow Selectivity Coefficient Rothmund and Kornfeld Selectivity Coefficient Gapon Selectivity Coefficient Gaines and Thomas Selectivity Coefficient Davies Selectivity Coefficient Regular Solution Model Exchange Isotherms and Preference Exchange Equilibrium Constant Exercises 440 References 442 Chapter 9 Oxidation-Reduction Reactions in Soils The Electron Activity Redox Potential Measurements Redox Status in Soils Reduction-Oxidation Sequences in Soils Redox Zones pe-ph Predominance Diagrams Construction of pe-ph Diagrams: The Cr-H 2 O System Examples of pe-ph Diagrams for Redox-Sensitive Elements Iron and Manganese Selenium Arsenic Exercises 471 References 472

6 Chapter 10 Acidity in Soil Materials The Measurement of Soil Solution ph The ph Electrode System Soil Solution ph Chemical and Biochemical Processes that Influence Soil Solution ph Acid-Neutralizing Capacity and the Quantification of Soil Acidity Neutralization of Soil Acidity Acid Generation and Management in Mine Spoils: The Oxidation of Pyrite Acid Generation and Neutralization in Pyritic Wastes Pyritic Mine Spoil Reclamation: Case Study Exercises. 495 References 497 Chapter 11 Soil Salinity and Sodicity Sources of Salts Diagnostic Characteristics of Saline and Sodic Soils Irrigation Water Quality Parameters and Relationships Genesis, Management, and Reclamation of Salt-Affected Soils Saline Soils Sodic Soils Classification of Sodic Soils Flocculation and Dispersion in Colloidal Suspensions Genesis and Management of Sodic Soils Sodic Mine Spoil Reclamation Exercises 519 References 521 Index 523