Kabay / Bryjak / Hilal Boron Separation Processes

1. Auflage 2015
ISBN: 978-0-444-63465-8
Verlag: Elsevier Science & Techn.
Format: EPUB
Kopierschutz: 6 - ePub Watermark

E-Book, Englisch, 412 Seiten

The impending crisis posed by water stress and poor sanitation represents one of greatest human challenges for the 21st century, and membrane technology has emerged as a serious contender to confront the crisis. Yet, whilst there are countless texts on wastewater treatment and on membrane technologies, none address the boron problem and separation processes for boron elimination. Boron Separation Processes fills this gap and provides a unique and single source that highlights the growing and competitive importance of these processes. For the first time, the reader is able to see in one reference work the state-of-the-art research in this rapidly growing field. The book focuses on four main areas: - Effect of boron on humans and plants - Separation of boron by ion exchange and adsorption processes - Separation of boron by membrane processes - Simulation and optimization studies for boron separation - Provides in one source a state-of-the-art overview of this compelling area - Reviews the environmental impact of boron before introducing emerging boron separation processes - Includes simulation and optimization studies for boron separation processes - Describes boron separation processes applicable to specific sources, such as seawater, geothermal water and wastewater

Autoren/Hrsg.

Kabay, Nalan

Bryjak, Marek

Hilal, Nidal

Inhaltsverzeichnis

1;Front Cover;1
2;Boron Separation Processes;4
3;Copyright;5
4;CONTENTS;6
5;EDITORS' PREFACE;8
5.1;SECTION 1—BORON IN THE ENVIRONMENT;8
5.2;SECTION 2—REMOVAL OF BORON BY ION EXCHANGE AND ADSORPTION PROCESSES;9
5.3;SECTION 3—REMOVAL OF BORON BY MEMBRANE PROCESSES;9
5.4;SECTION 4—SIMULATION AND OPTIMIZATION STUDIES;10
6;CONTRIBUTORS;12
7;Chapter 1 - Boron in the Environment;16
7.1;1.1 BORON HISTORY, SOURCES, CHEMISTRY, AND APPLICATIONS;16
7.2;1.2 BORON SOURCES AND CYCLES IN THE ENVIRONMENT;18
7.3;1.3 BORON IN ATMOSPHERE, NATURAL WATERS, AND SOIL;23
7.4;1.4 EFFECT OF BORON ON MICROBIOTA AND PLANTS;33
7.5;1.5 EFFECT OF BORON ON ANIMALS AND HUMANS;36
7.6;ACKNOWLEDGMENTS;40
7.7;REFERENCES;40
8;Chapter 2 - The Chemistry of Boron in Water;50
8.1;2.1 BORON AND ITS CHEMICAL PROPERTIES;50
8.2;2.2 BORON IN NATURE;52
8.3;2.3 PHYSICOCHEMISTRY OF BORON COMPOUNDS IN WATER;54
8.4;2.4 COMPLEXATION OF BORON SPECIES IN WATER;61
8.5;2.5 BORON AND DRINKING WATER REGULATIONS;71
8.6;2.6 ANALYTICAL METHODS FOR MEASURING BORON CONTENT IN WATER;72
8.7;REFERENCES;75
9;Chapter 3 - Risk Assessment of Borates in Occupational Settings;80
9.1;3.1 INTRODUCTION;80
9.2;3.2 TOXICOKINETICS;80
9.3;3.3 HEALTH RISK ASSESSMENT;81
9.4;3.4 CONCLUSION;115
9.5;REFERENCES;117
10;Chapter 4 - Ion Exchange Borate Kinetics;122
10.1;4.1 INTRODUCTION;122
10.2;4.2 BORATE IONIC CHEMISTRY;122
10.3;4.3 SORPTION MECHANISM OF BORON ON ION EXCHANGER;128
10.4;4.4 SORPTION EQUILIBRIUM AND KINETICS;133
10.5;REFERENCES;143
11;Chapter 5 - Separation and Recovery of Boron From Various Resources Using Chelate Adsorbents;146
11.1;5.1 INTRODUCTION;146
11.2;5.2 REMOVAL TECHNOLOGY OF BORON FROM AQUEOUS SOLUTION;147
11.3;5.3 ADSORPTION BEHAVIOR OF BORON BY CHELATE RESINS AND CHELATING FIBERS;149
11.4;5.4 CHROMATOGRAPHIC SEPARATION OF BORON FROM AQUEOUS SOLUTION;153
11.5;5.5 BORON REMOVAL FROM GEOTHERMAL WATER;155
11.6;5.6 BORON RECOVERY FROM SALT LAKE BRINE;158
11.7;REFERENCES;159
12;Chapter 6 - Adsorption of Boron by Minerals, Clays, and Soils;162
12.1;6.1 INTRODUCTION;162
12.2;6.2 ADSORPTION OF BORON ON MINERALS AND CLAYS;162
12.3;6.3 ADSORPTION OF BORON ON SOILS AND HUMIC ACIDS;178
12.4;REFERENCES;181
13;Chapter 7 - Iminobis-Alkylene Diol Function as Alternative Boron-Chelating Group: Its Incorporation into Various Polymer To ...;184
13.1;7.1 INTRODUCTION;184
13.2;7.2 DESIGN CRITERIA FOR BORON-CHELATING POLYMERS;184
13.3;7.3 CARRIER POLYMERS;191
13.4;7.4 LINEAR BORON-CHELATING POLYMERS AND THEIR USE IN POLYMER-ENHANCED ULTRAFILTRATION: WHAT IS THE IDEA BEHIND IT?;192
13.5;7.5 SYNTHESIS OF WATER-SOLUBLE BORON-BINDING FUNCTIONAL POLYMERS;193
13.6;7.6 BORON-CHELATING GEL POLYMERS;200
13.7;7.7 RESIN BEADS WITH BORON-CHELATING LIGANDS;201
13.8;7.8 IBP FUNCTIONAL SURFACE BRUSHES TETHERED TO CROSS-LINKED POLYMER MICROSPHERES;205
13.9;7.9 BORON BINDING SELECTIVITY OF IBP AND RELATED FUNCTIONS: EFFECT OF FOREIGN IONS;208
13.10;7.10 CONCLUDING REMARKS;210
13.11;REFERENCES;210
14;Chapter 8 - Boron Removal Using Membranes;214
14.1;8.1 INTRODUCTION;214
14.2;8.2 BORON REJECTION BY RO MEMBRANES;216
14.3;8.3 REJECTION MECHANISM AND MEMBRANE DEVELOPMENT FOR IMPROVED BORON REJECTION;218
14.4;8.4 RO SYSTEMS CONFIGURATIONS FOR BORON REDUCTION;222
14.5;8.5 OTHER POSSIBLE RO/UF/MF TECHNIQUES FOR BORON REMOVAL;224
14.6;8.6 BORON REMOVAL BY ELECTRODIALYSIS;226
14.7;8.7 THE COST OF BORON REMOVAL;228
14.8;REFERENCES;228
15;Chapter 9 - Boron Removal From Seawater Using Reverse Osmosis Integrated Processes;234
15.1;9.1 INTRODUCTION;234
15.2;9.2 BORON CHEMISTRY;235
15.3;9.3 REMOVAL OF BORON FROM SEAWATER BY SEAWATER REVERSE OSMOSIS PROCESS;235
15.4;9.4 REMOVAL OF BORON FROM SEAWATER BY INTEGRATED PROCESSES;238
15.5;9.5 REMOVAL OF BORON FROM SEAWATER BY ION EXCHANGE;238
15.6;9.6 REMOVAL OF BORON FROM SEAWATER BY SORPTION–MEMBRANE FILTRATION HYBRID PROCESS;241
15.7;9.7 OTHER MEMBRANE-BASED HYBRID PROCESSES FOR REMOVAL OF BORON FROM RO PERMEATE;243
15.8;9.8 OTHER MEMBRANE-BASED SEPARATION METHODS FOR BORON REMOVAL;244
15.9;9.9 COST OF BORON REMOVAL FOR SWRO DESALINATION;245
15.10;9.10 COMPARATIVE ANALYSIS OF PROCESSES USED FOR BORON REMOVAL FROM SEAWATER;246
15.11;9.11 CONCLUSIONS;246
15.12;REFERENCES;248
16;Chapter 10 - Boron Removal From Water by Sorption–Membrane Filtration Hybrid Process;252
16.1;10.1 INTRODUCTION;252
16.2;10.2 MOLECULE-ENHANCED MEMBRANE SEPARATION;254
16.3;10.3 POLYMER-ENHANCED ULTRAFILTRATION;254
16.4;10.4 MICELLAR-ENHANCED ULTRAFILTRATION AND COLLOID-ENHANCED ULTRAFILTRATION;255
16.5;10.5 SUSPENSION-ENHANCED MICROFILTRATION OR ULTRAFILTRATION;255
16.6;10.6 CONCLUSIONS;262
16.7;REFERENCES;262
17;Chapter 11 - Boron Removal Using Ion Exchange Membranes;264
17.1;11.1 INTRODUCTION;264
17.2;11.2 BORON SPECIES IN AQUEOUS SOLUTION;265
17.3;11.3 REPORTS ON BORIC ACID TRANSPORT ACROSS ION EXCHANGE MEMBRANES FROM WATERS WITH PH <9.0;267
17.4;11.4 REPORTS ON BORATE TRANSPORT ACROSS ION EXCHANGE MEMBRANES FROM WATERS WITH PH .9;272
17.5;11.5 REPORTS ON BORATE TRANSPORT ACROSS ION EXCHANGE MEMBRANES BY DONNAN DIALYSIS;275
17.6;11.6 BORON REMOVAL BY EDI;276
17.7;11.7 THE REPORTED COSTS OF BORON REMOVAL WITH ION EXCHANGE MEMBRANES;277
17.8;11.8 CONCLUSIONS;278
17.9;REFERENCES;279
18;Chapter 12 - Boron Removal From Geothermal Water Using Membrane Processes;282
18.1;12.1 INTRODUCTION;282
18.2;12.2 BORON IN GEOTHERMAL WATER AND ITS REMOVAL;283
18.3;12.3 CONCLUSIONS;294
18.4;ACKNOWLEDGMENT;295
18.5;REFERENCES;295
19;Chapter 13 - Basic Principles of Simulating Boron Removal in Reverse Osmosis Processes;300
19.1;13.1 WATER PERMEATION, SOLUTE TRANSPORT, AND CONCENTRATION POLARIZATION;300
19.2;13.2 SPIRAL WOUND ELEMENT SIMULATION;303
19.3;13.3 MODEL PARAMETER ESTIMATION;306
19.4;13.4 PILOT- AND FULL-SCALE SIMULATION;307
19.5;13.5 SUMMARY;310
19.6;REFERENCES;311
20;Chapter 14 - Single SWRO Pass Boron Removal at High pH: Prospects and Challenges;312
20.1;14.1 INTRODUCTION AND PROSPECTS;312
20.2;14.2 APPROACH CHALLENGES AND POTENTIAL SOLUTIONS;316
20.3;REFERENCES;335
21;Chapter 15 - Seawater Reverse Osmosis Permeate: Comparative Evaluation of Boron Removal Technologies;340
21.1;15.1 INTRODUCTION;340
21.2;15.2 MATERIALS AND METHOD;341
21.3;15.3 CASE STUDIES;347
21.4;15.4 AHP AND HASSE DIAGRAM IMPLEMENTATION;349
21.5;15.5 CONCLUSIONS;351
21.6;ABBREVIATIONS AND SYMBOLS;351
21.7;REFERENCES;352
22;Chapter 16 - Hybrid Adsorption–Microfiltration Process with Plug Flow of Microparticulate Adsorbent for Boron Removal;354
22.1;16.1 INTRODUCTION;354
22.2;16.2 AMF PROCESS;356
22.3;16.3 MF OF ADSORBENT SUSPENSIONS;358
22.4;16.4 SIMULATION OF HYBRID AMF PROCESS;362
22.5;16.5 COMPARISON OF AMF PROCESS WITH CLASSICAL IEX IN COLUMNS;366
22.6;16.6 CONCLUSIONS;367
22.7;16.7 NOMENCLATURE;367
22.8;ACKNOWLDGMENT;368
22.9;REFERENCES;368
23;Chapter 17 - Boron Uptake from Aqueous Solution by Chelating Adsorbents: A Statistical Experimental Design Approach;370
23.1;17.1 INTRODUCTION;370
23.2;17.2 MATERIALS AND METHODS;371
23.3;17.3 RESULTS AND DISCUSSION;377
23.4;17.4 CONCLUSIONS;393
23.5;REFERENCES;395
24;INDEX;398

Leseproben

Chapter 2

The Chemistry of Boron in Water

Victor Kochkodan, Nawaf Bin Darwish,  and Nidal Hilal     Centre for Water Advanced Technologies and Environmental Research (CWATER), College of Engineering, Swansea University, Swansea, UK

Abstract

The chapter describes boron chemistry in aqueous solutions. The physicochemical properties of boron as a chemical element, boron distribution in the Earth's lithosphere/hydrosphere, and the pathways of boron entering the aqueous environmental are discussed. The data on boron content in surface waters, underground waters, and seawater are presented, and the distribution of boron compounds and their concentrations in aqueous solutions at different pH are described. The chemistry of boron-containing species in aqueous solutions is analyzed in detail. Finally, the current regulations for boron content in drinking water as well as analytical techniques for boron quantification in water are presented.

Keywords

Boron; Boron chemistry; Water

2.1. Boron and Its Chemical Properties

Boron (B) is the fifth element in the periodic table with an atomic mass of 10.81. It is the most electronegative element of Group III, and boron's chemical properties closely resemble those of the nonmetals, particularly silicon.

Pure elemental boron was first isolated simultaneously and independently in 1808 by H. Davy in England, who observed that an electric current sent through a solution of borates produced a brown precipitate on one of the electrodes, and by J. Gay-Lussac and L. Thenard in France, who obtained boron by reducing boric acid with iron at high temperatures.1

Elemental boron exists as a solid at room temperature, either as black monoclinic crystals or as a yellow or brown amorphous powder when impure. Amorphous boron can be obtained by the reduction of boron oxide with sodium or potassium fluoroborate with potassium1:

2O3+6Na=2B+3Na2O

4+3K=4KF4+B

Crystalline boron was first prepared when hydrogen and boron bromide vapors at a rather less-than atmospheric pressure were passed over a tantalum filament heated to 1000–1300°C.2 At this temperature, the bromide is reduced, and the boron thus becomes deposited on the filament as black hexagonal flakes and needles:

BBR3+3H2=6HBr+2B

Two crystalline modifications of boron, namely, a-rhombohedral boron (Figure 2.1) and ß-rhombohedral boron (Figure 2.2) exist at atmospheric pressure. The latter is believed to be thermodynamically stable at high temperatures, whereas a-boron is sometimes called the low-temperature form.3

The chemical nature of boron is influenced primarily by its small size (covalent radius of boron of 0.8–1.01Å) and high ionization energy (344.2kJ/mol).1 The high affinity for oxygen is another dominant characteristic of boron, which forms the basis of the extensive chemistry of borates and related oxocomplexes.2

Figure 2.1 Unit cells of a-boron.

(a) Hexagonal setting and (b) rhombohedral setting.3

Figure 2.2 Unit cells of ß-boron.

(a) Hexagonal setting and (b) rhombohedral setting.3

The chemical properties of the boron element depend also on its morphology and particle size. Micron sized amorphous boron reacts easily and sometimes intensely, whereas crystalline boron is very inert chemically and resistant to attack even by boiling hydrofluoric or hydrochloric acid. It should be noted that boron is difficult to prepare in a state of high purity owing to its very high melting point of 2079°C.4 The boiling point of boron is 2250°C, and its density is 2.37g/m3.5

The electron structure of the element is 1s2 2s2 2p1 and hence boron can form three or four valence bonds. In its most common compounds, such as oxides, sulfides, nitrides, and halides, boron has the formal oxidation state of +3. In these compounds, the bonds are coplanar, with interbond angles of 120°. The lower oxidation states +1 or 0 are present only in compounds such as higher boranes (e.g., B5H9), subvalent halides (e.g., B4Cl4), metal borides (e.g., Ti2B), or in some compounds containing multiple B–B bonds.2 In naturally occurring compounds, boron usually has a coordination number of either 3 or 4.

Boron salts are generally very water soluble, for example, borax has a water solubility of 25.2g/L, while boron trifluoride is the least water-soluble boron compound, with a water solubility of 2.4g/L.2

2.2. Boron in Nature

Boron element is composed of 8B, 10B, 11B, 12B, and 13B isotopes. The most stable isotopes are 10B and 11B. The occurrence of these isotopes in nature is 19.1–20.3% and 79.7–80.9%, respectively.1

2.2.1. Boron in the Lithosphere

Boron is widely distributed in lithosphere of the earth.6 It is found in rocks and soils, particularly in clay-rich marine sediments. The concentration of boron in the Earth's crust varies from 1 to 500mg/kg, depending on the nature of the rock.7 According to Krauskopf,8 the average boron in the earth's crust is around 10mg/kg, representing 0.001% of the elemental composition of the earth. The amount of boron in soils ranges from 2 to 100mg/kg with an average of 30mg/kg.7 Most soils have a low boron content (<10mgB/kg), while high-boron-content soils (10–100mgB/kg) are usually associated with volcanic activity.

The total amount of boron stored in the lithosphere is estimated as the continental and oceanic crusts (1018kgB), coal deposits (1010kgB), commercial borate deposits (1010kgB), and biomass (1010kgB).9

It should be noted that boron is never found free in nature, but it invariably occurs as the oxide B2O3 in combination with the oxides of other elements to form borates of greater or lesser complexity. There are >200 boron compounds in the Earth, but only 12 are commercially significant.10 The first known borate mineral to antiquity is sodium tetraborate decahydrate Na2B4O7×10H2O or borax (Figure 2.3(a)). An early use of borax was to make perborate, the beaching agent once widely used in household detergents. The other important boron-containing minerals are ulexite (NaCaB5O9·8H2O), colemanite (Ca2B6O11·5H2O) (Figure 2.3(b)), and kernite (Na2B4O7·4H2O). Borax, colemanite, ulexite, and kernite provide >90% of the world's boron demand.10 The occurrence of concentrated deposits of borate minerals is intimately connected with past or present volcanic activity and arid climatic conditions are essential for continued preservation of such deposits, which are being exploited in the USA, Turkey, Italy, Spain, Russia, Chile, and some other countries.

Figure 2.3 Photographs of boron-containing minerals.

Borax (a) and colemanite (b).

2.2.2. Boron in the Aqueous Environment

The majority of the Earth's boron is found in the oceans, with an average concentration of 4.5mg/L, but it ranges from 0.5 to 9.6mg/L.11 For example, the boron content in the Mediterranean sea may be as high as 9.6mg/L.9

The natural borate content of ground water and surface water is usually small and is a result of leaching from rocks and soils containing borates and borosilicates. Concentrations of boron in ground water throughout the world range widely, from <0.3 to >100mg/L. In the European Union (EU), concentrations of boron change from 0.5 to 1.5mg/L for southern Europe (Italy, Spain) and up to approximately 0.6mg/L for northern Europe (Denmark, Germany, UK).12

The amount of boron in surface water depends on factors such as the proximity to marine coastal regions, inputs from industrial and municipal effluents, and the geochemical nature of the drainage area. Boron concentrations in surface water range from <0.001 to 2mg/L in EU, with mean values typically below 0.6mg/L.12 A similar boron content has been reported for water bodies within Turkey, Russia, and Pakistan, from 0.01 to 7mg/L, with most values being <0.5mg/L. Concentrations of boron in surface waters of North America (Canada, USA) range from 0.02 to 360mg/L, indicative of boron-rich deposits, up to 0.01mg/L in Japan and up to 0.3mg/L...