ATHANASIOS K. KARAMALIDIS is a Research Assistant Professor in the Department of Civil and Environmental Engineering at Carnegie Mellon University. He has conducted research on the dissolution and surface reactions of complex mineral assemblages in aqueous systems. He has published his work in peer-reviewed international journals in environmental engineering and science, and in the proceedings of international conferences.DAVID A. DZOMBAK is the Walter J. Blenko Sr. Professor of Environmental Engineering in the Department of Civil and Environmental Engineering at Carnegie Mellon University. He is also Faculty Director of the Steinbrenner Institute for Environmental Education and Research. He has published numerous articles in leading environmental engineering and science journals, book chapters, articles for the popular press, and has authored two books.

• Foreword xiPreface xiii1 Aluminum Oxides and Hydroxides under Environmental Conditions 11.1 Introduction 11.2 Occurrence of Aluminum Oxides and Hydroxides in the Subsurface 21.3 Occurrence of Aluminum Oxides and Hydroxides in Surface Water 41.4 Use of Aluminum Hydroxide in Water Treatment 61.5 Summary 72 Formation and Properties of Gibbsite and Closely Related Minerals 92.1 Al Polymerization Models 92.1.1 The “Core-Links” Model 102.1.2 The “Cage-Like” (Keggin-Al 13 Structure) Model 102.1.3 The “Continuous” Model 112.2 Formation of Gibbsite and Other Al Hydroxides and Oxyhydroxides 122.3 Aluminum Hydroxide Polymorphs: Structure and Nomenclature 152.4 Gibbsite 192.4.1 Kinetics of Precipitation and Crystal Growth 192.4.2 Structure 212.4.3 Common Techniques of Synthesis 212.4.4 Synthesized Gibbsite and Differences from Natural Gibbsite 242.5 Bayerite 252.5.1 Kinetics of Precipitation and Crystal Growth 252.5.2 Structure 262.5.3 Differences from Gibbsite 262.5.4 Synthesized Bayerite and Transformation to Gibbsite 272.6 Nordstrandite 272.7 Doyleite 282.8 Other Forms of Aluminum Oxides and Oxyhydroxides 282.8.1 Corundum (a-Al 2 O 3) 282.8.2 Boehmite (g-AlOOH) 292.8.3 Diaspore (a-AlOOH) 292.9 Other Forms Manufactured under High Temperature and Pressure 303 Types of Available Data 333.1 Gibbsite Structure Verification 333.2 Physical–Chemical Properties 343.2.1 Specific Surface Area 343.2.2 Surface Site Characterization 353.2.2.1 Hydroxyl Surface Sites 353.2.2.2 Surface Site Density 363.3 Acid–Base Titration Data 373.4 Cation and Anion-Sorption Data 403.5 Spectroscopic Data for Sorption on Gibbsite 413.6 Proton ReleaseUptake Data 433.7 Electrokinetic Data 433.8 Summary 444 Data Compilation and Treatment Methods 454.1 Collection of Data 454.2 Assessment of Data Quality 464.2.1 Solid Preparation Method 464.2.2 Type of Reaction Vessel 474.2.3 Nature of Background Electrolyte 474.2.4 Sorption Kinetics 484.2.4.1 Proton Sorption Kinetics 484.2.4.2 Cation and Anion Sorption Kinetics 494.2.5 Method of Solid–Liquid Separation 494.2.6 CO 2 Exclusion 504.2.7 Experimental Temperature 514.3 Compilation of Surface Properties 514.4 Extraction of Equilibrium Sorption Constants 514.4.1 Solution Activity Coefficients 524.4.2 Fiteql 524.4.3 Data Grouping 544.4.4 Selection of Surface Species 544.4.5 Selection of Best Estimates 554.5 Optimal-Fit Simulations 564.6 Presentation of Results 565 Surface Properties of Gibbsite 595.1 Surface Area 595.2 Site Density 625.3 Point of Zero Charge 645.4 Surface Acid–Base Chemistry 655.5 Effects of Dissolution on Gibbsite Surface Acid–Base Chemistry 765.6 Summary 806 Cation Sorption on Gibbsite 816.1 Modeling Methodology and Reactions 816.2 Available Spectroscopic Data and Use in Modeling 866.2.1 Copper 866.2.2 Lead 876.2.3 Cobalt 886.2.4 Cadmium 886.2.5 Manganese 886.2.6 Iron(II) 886.2.7 Calcium 886.2.8 Zinc 896.2.9 Mercury 896.2.10 Uranium 906.2.11 Thorium 916.3 Copper 926.4 Lead 996.5 Cobalt 1076.6 Cadmium 1176.7 Manganese 1266.8 Iron (II) 1276.9 Calcium 1286.10 Zinc 1306.11 Mercury 1326.12 Uranium 1426.13 Thorium 1457 Anion Sorption on Gibbsite 1497.1 Modeling Methodology and Reactions 1497.2 Available Spectroscopic Data and Use in Modeling 1537.2.1 Phosphate 1537.2.2 Arsenate 1547.2.3 Arsenite 1547.2.4 Molybdate 1557.2.5 Selenate 1557.2.6 Chromate 1557.2.7 Borate 1557.2.8 Sulfate 1567.2.9 Fluoride 1567.2.10 Silicate 1567.3 Phosphate 1577.4 Arsenate 1647.5 Arsenite 1767.6 Molybdate 1827.7 Selenate 1857.8 Chromate 1877.9 Borate 1887.10 Sulfate 1927.11 Fluoride 1957.12 Silicate 1978 Coherence and Extrapolation of the Results 1998.1 Cation Sorption on Gibbsite 1998.2 Anion Sorption on Gibbsite 2048.3 Comparison of Gibbsite Surface-Complexation Constants with Those of Goethite, Hydrous Ferric Oxide, and Hydrous Manganese Oxide 2088.4 Summary 213References 219Appendix A: Summary of Experimental Details 241Author Index 283Subject Index 289

ATHANASIOS K. KARAMALIDIS is a Research Assistant Professor in the Department of Civil and Environmental Engineering at Carnegie Mellon University. He has conducted research on the dissolution and surface reactions of complex mineral assemblages in aqueous systems. He has published his work in peer-reviewed international journals in environmental engineering and science, and in the proceedings of international conferences.DAVID A. DZOMBAK is the Walter J. Blenko Sr. Professor of Environmental Engineering in the Department of Civil and Environmental Engineering at Carnegie Mellon University. He is also Faculty Director of the Steinbrenner Institute for Environmental Education and Research. He has published numerous articles in leading environmental engineering and science journals, book chapters, articles for the popular press, and has authored two books.

• Foreword xiPreface xiii1 Aluminum Oxides and Hydroxides under Environmental Conditions 11.1 Introduction 11.2 Occurrence of Aluminum Oxides and Hydroxides in the Subsurface 21.3 Occurrence of Aluminum Oxides and Hydroxides in Surface Water 41.4 Use of Aluminum Hydroxide in Water Treatment 61.5 Summary 72 Formation and Properties of Gibbsite and Closely Related Minerals 92.1 Al Polymerization Models 92.1.1 The “Core-Links” Model 102.1.2 The “Cage-Like” (Keggin-Al 13 Structure) Model 102.1.3 The “Continuous” Model 112.2 Formation of Gibbsite and Other Al Hydroxides and Oxyhydroxides 122.3 Aluminum Hydroxide Polymorphs: Structure and Nomenclature 152.4 Gibbsite 192.4.1 Kinetics of Precipitation and Crystal Growth 192.4.2 Structure 212.4.3 Common Techniques of Synthesis 212.4.4 Synthesized Gibbsite and Differences from Natural Gibbsite 242.5 Bayerite 252.5.1 Kinetics of Precipitation and Crystal Growth 252.5.2 Structure 262.5.3 Differences from Gibbsite 262.5.4 Synthesized Bayerite and Transformation to Gibbsite 272.6 Nordstrandite 272.7 Doyleite 282.8 Other Forms of Aluminum Oxides and Oxyhydroxides 282.8.1 Corundum (a-Al 2 O 3) 282.8.2 Boehmite (g-AlOOH) 292.8.3 Diaspore (a-AlOOH) 292.9 Other Forms Manufactured under High Temperature and Pressure 303 Types of Available Data 333.1 Gibbsite Structure Verification 333.2 Physical–Chemical Properties 343.2.1 Specific Surface Area 343.2.2 Surface Site Characterization 353.2.2.1 Hydroxyl Surface Sites 353.2.2.2 Surface Site Density 363.3 Acid–Base Titration Data 373.4 Cation and Anion-Sorption Data 403.5 Spectroscopic Data for Sorption on Gibbsite 413.6 Proton ReleaseUptake Data 433.7 Electrokinetic Data 433.8 Summary 444 Data Compilation and Treatment Methods 454.1 Collection of Data 454.2 Assessment of Data Quality 464.2.1 Solid Preparation Method 464.2.2 Type of Reaction Vessel 474.2.3 Nature of Background Electrolyte 474.2.4 Sorption Kinetics 484.2.4.1 Proton Sorption Kinetics 484.2.4.2 Cation and Anion Sorption Kinetics 494.2.5 Method of Solid–Liquid Separation 494.2.6 CO 2 Exclusion 504.2.7 Experimental Temperature 514.3 Compilation of Surface Properties 514.4 Extraction of Equilibrium Sorption Constants 514.4.1 Solution Activity Coefficients 524.4.2 Fiteql 524.4.3 Data Grouping 544.4.4 Selection of Surface Species 544.4.5 Selection of Best Estimates 554.5 Optimal-Fit Simulations 564.6 Presentation of Results 565 Surface Properties of Gibbsite 595.1 Surface Area 595.2 Site Density 625.3 Point of Zero Charge 645.4 Surface Acid–Base Chemistry 655.5 Effects of Dissolution on Gibbsite Surface Acid–Base Chemistry 765.6 Summary 806 Cation Sorption on Gibbsite 816.1 Modeling Methodology and Reactions 816.2 Available Spectroscopic Data and Use in Modeling 866.2.1 Copper 866.2.2 Lead 876.2.3 Cobalt 886.2.4 Cadmium 886.2.5 Manganese 886.2.6 Iron(II) 886.2.7 Calcium 886.2.8 Zinc 896.2.9 Mercury 896.2.10 Uranium 906.2.11 Thorium 916.3 Copper 926.4 Lead 996.5 Cobalt 1076.6 Cadmium 1176.7 Manganese 1266.8 Iron (II) 1276.9 Calcium 1286.10 Zinc 1306.11 Mercury 1326.12 Uranium 1426.13 Thorium 1457 Anion Sorption on Gibbsite 1497.1 Modeling Methodology and Reactions 1497.2 Available Spectroscopic Data and Use in Modeling 1537.2.1 Phosphate 1537.2.2 Arsenate 1547.2.3 Arsenite 1547.2.4 Molybdate 1557.2.5 Selenate 1557.2.6 Chromate 1557.2.7 Borate 1557.2.8 Sulfate 1567.2.9 Fluoride 1567.2.10 Silicate 1567.3 Phosphate 1577.4 Arsenate 1647.5 Arsenite 1767.6 Molybdate 1827.7 Selenate 1857.8 Chromate 1877.9 Borate 1887.10 Sulfate 1927.11 Fluoride 1957.12 Silicate 1978 Coherence and Extrapolation of the Results 1998.1 Cation Sorption on Gibbsite 1998.2 Anion Sorption on Gibbsite 2048.3 Comparison of Gibbsite Surface-Complexation Constants with Those of Goethite, Hydrous Ferric Oxide, and Hydrous Manganese Oxide 2088.4 Summary 213References 219Appendix A: Summary of Experimental Details 241Author Index 283Subject Index 289

ATHANASIOS K. KARAMALIDIS is a Research Assistant Professor in the Department of Civil and Environmental Engineering at Carnegie Mellon University. He has conducted research on the dissolution and surface reactions of complex mineral assemblages in aqueous systems. He has published his work in peer-reviewed international journals in environmental engineering and science, and in the proceedings of international conferences.DAVID A. DZOMBAK is the Walter J. Blenko Sr. Professor of Environmental Engineering in the Department of Civil and Environmental Engineering at Carnegie Mellon University. He is also Faculty Director of the Steinbrenner Institute for Environmental Education and Research. He has published numerous articles in leading environmental engineering and science journals, book chapters, articles for the popular press, and has authored two books.

• Foreword xiPreface xiii1 Aluminum Oxides and Hydroxides under Environmental Conditions 11.1 Introduction 11.2 Occurrence of Aluminum Oxides and Hydroxides in the Subsurface 21.3 Occurrence of Aluminum Oxides and Hydroxides in Surface Water 41.4 Use of Aluminum Hydroxide in Water Treatment 61.5 Summary 72 Formation and Properties of Gibbsite and Closely Related Minerals 92.1 Al Polymerization Models 92.1.1 The “Core-Links” Model 102.1.2 The “Cage-Like” (Keggin-Al 13 Structure) Model 102.1.3 The “Continuous” Model 112.2 Formation of Gibbsite and Other Al Hydroxides and Oxyhydroxides 122.3 Aluminum Hydroxide Polymorphs: Structure and Nomenclature 152.4 Gibbsite 192.4.1 Kinetics of Precipitation and Crystal Growth 192.4.2 Structure 212.4.3 Common Techniques of Synthesis 212.4.4 Synthesized Gibbsite and Differences from Natural Gibbsite 242.5 Bayerite 252.5.1 Kinetics of Precipitation and Crystal Growth 252.5.2 Structure 262.5.3 Differences from Gibbsite 262.5.4 Synthesized Bayerite and Transformation to Gibbsite 272.6 Nordstrandite 272.7 Doyleite 282.8 Other Forms of Aluminum Oxides and Oxyhydroxides 282.8.1 Corundum (a-Al 2 O 3) 282.8.2 Boehmite (g-AlOOH) 292.8.3 Diaspore (a-AlOOH) 292.9 Other Forms Manufactured under High Temperature and Pressure 303 Types of Available Data 333.1 Gibbsite Structure Verification 333.2 Physical–Chemical Properties 343.2.1 Specific Surface Area 343.2.2 Surface Site Characterization 353.2.2.1 Hydroxyl Surface Sites 353.2.2.2 Surface Site Density 363.3 Acid–Base Titration Data 373.4 Cation and Anion-Sorption Data 403.5 Spectroscopic Data for Sorption on Gibbsite 413.6 Proton ReleaseUptake Data 433.7 Electrokinetic Data 433.8 Summary 444 Data Compilation and Treatment Methods 454.1 Collection of Data 454.2 Assessment of Data Quality 464.2.1 Solid Preparation Method 464.2.2 Type of Reaction Vessel 474.2.3 Nature of Background Electrolyte 474.2.4 Sorption Kinetics 484.2.4.1 Proton Sorption Kinetics 484.2.4.2 Cation and Anion Sorption Kinetics 494.2.5 Method of Solid–Liquid Separation 494.2.6 CO 2 Exclusion 504.2.7 Experimental Temperature 514.3 Compilation of Surface Properties 514.4 Extraction of Equilibrium Sorption Constants 514.4.1 Solution Activity Coefficients 524.4.2 Fiteql 524.4.3 Data Grouping 544.4.4 Selection of Surface Species 544.4.5 Selection of Best Estimates 554.5 Optimal-Fit Simulations 564.6 Presentation of Results 565 Surface Properties of Gibbsite 595.1 Surface Area 595.2 Site Density 625.3 Point of Zero Charge 645.4 Surface Acid–Base Chemistry 655.5 Effects of Dissolution on Gibbsite Surface Acid–Base Chemistry 765.6 Summary 806 Cation Sorption on Gibbsite 816.1 Modeling Methodology and Reactions 816.2 Available Spectroscopic Data and Use in Modeling 866.2.1 Copper 866.2.2 Lead 876.2.3 Cobalt 886.2.4 Cadmium 886.2.5 Manganese 886.2.6 Iron(II) 886.2.7 Calcium 886.2.8 Zinc 896.2.9 Mercury 896.2.10 Uranium 906.2.11 Thorium 916.3 Copper 926.4 Lead 996.5 Cobalt 1076.6 Cadmium 1176.7 Manganese 1266.8 Iron (II) 1276.9 Calcium 1286.10 Zinc 1306.11 Mercury 1326.12 Uranium 1426.13 Thorium 1457 Anion Sorption on Gibbsite 1497.1 Modeling Methodology and Reactions 1497.2 Available Spectroscopic Data and Use in Modeling 1537.2.1 Phosphate 1537.2.2 Arsenate 1547.2.3 Arsenite 1547.2.4 Molybdate 1557.2.5 Selenate 1557.2.6 Chromate 1557.2.7 Borate 1557.2.8 Sulfate 1567.2.9 Fluoride 1567.2.10 Silicate 1567.3 Phosphate 1577.4 Arsenate 1647.5 Arsenite 1767.6 Molybdate 1827.7 Selenate 1857.8 Chromate 1877.9 Borate 1887.10 Sulfate 1927.11 Fluoride 1957.12 Silicate 1978 Coherence and Extrapolation of the Results 1998.1 Cation Sorption on Gibbsite 1998.2 Anion Sorption on Gibbsite 2048.3 Comparison of Gibbsite Surface-Complexation Constants with Those of Goethite, Hydrous Ferric Oxide, and Hydrous Manganese Oxide 2088.4 Summary 213References 219Appendix A: Summary of Experimental Details 241Author Index 283Subject Index 289