1 Nanotechnology and Environmental Nanotechnology 1

1.1 Nanoscale 1

1.2 Nanotechnology: A Short History 3

1.3 Nanotechnology in Water Research 7

References 9

2 Overview of Engineered Nanoparticles 11

2.1 Nanoparticle Basics 11

2.2 Two Important Properties 12

2.3 Prime Nanoparticles 15

2.3.1 Carbon Nanoparticles 15

2.3.2 Metal Nanoparticles 20

2.3.3 Metal Oxide Nanoparticles 24

2.3.4 Other Inorganic Nanoparticles 25

2.3.5 Organic Nanoparticles 26

2.3.6 Natural Nanoparticles 26

2.3.7 Nanoplastics 27

2.4 Case Study: Nanoparticles and Sustainable Agriculture 29

2.4.1 Direct Effect of Engineered Nanoparticles on Plants 29

2.4.2 Nanoparticles for Controlled-Release Fertilizers 31

References 37

3 Nanotechnology and Water Quality Monitoring: Nanosensors 43

3.1 Sensor Basics 43

3.1.1 Overview of Sensors 43

3.1.2 Characteristics 46

3.1.3 Sensors in Water Research 47

3.2 Nanosensors and Their Applications 48

3.2.1 Overview 48

3.2.2 Carbon Nanoparticle-Based Sensors 49

3.2.3 Metal Nanoparticle-Based Sensors 51

3.2.4 Other Nanoparticle-Based Sensors 52

3.3 Case Studies of Nanosensors in Water Research 54

3.3.1 Graphene Film-Based Amperometric Sensors 54

3.3.2 Carbon Dots for Heavy Metal Detection 57

References 59

4 Nanotechnology and Groundwater Remediation 63

4.1 Groundwater Pollution 63

4.1.1 Overview 63

4.1.2 Sources of Groundwater Pollution 64

4.1.3 Groundwater Contaminants 66

4.2 Groundwater Remediation Technologies 69

4.2.1 Environmental Remediation 69

4.2.2 Groundwater Remediation 70

4.2.3 Pump and Treat 72

4.2.4 Bioremediation 72

4.2.5 Chemical Oxidation 74

4.2.6 Prb 74

4.3 Applications of Nanotechnology in Groundwater Remediation 76

4.3.1 Overview 76

4.3.2 Synthesis and Stability of nZVI 77

4.3.3 De-Contamination Mechanisms 81

4.4 Case Studies of nZVI for In Situ Groundwater Remediation 83

References 87

5 Nanotechnology and Water Purification: Membrane Filtration 93

5.1 Overview of Membrane Technology 93

5.2 Membranes in Water Purification 95

5.2.1 Hydraulic Pressure-Driven Membranes 95

5.2.2 MF and UF 96

5.2.3 NF and RO 98

5.2.4 Membrane Configuration 99

5.3 Theories of Membrane Filtration 100

5.4 Nanoparticles in Membranes for Water Purification 103

5.4.1 Arrangement of Engineered Nanoparticles in Membranes 104

5.4.2 Overview of Carbon Nanoparticle-Based Membranes 105

5.4.3 Carbon Nanotube-Based Membranes 105

5.4.3.1 MN-CNT Membranes 106

5.4.3.2 BP-CNT Membranes 107

5.4.3.3 VA-CNT Membranes 108

5.4.4 Graphene-Based Membranes 108

5.4.4.1 NG Membrane 109

5.4.4.2 Self-Standing GO/rGO Membranes 111

5.4.4.3 Graphene-Polymer Composite Membranes 113

5.4.5 Metal Nanoparticle-Polymer Composite Membranes 114

5.4.6 Metal Oxide Nanoparticle-Polymer Composite Membranes 114

5.4.7 Other Nanocomposite Membranes 115

References 116

6 Nanotechnology and Water Purification: Adsorbents 121

6.1 Overview of Adsorption 121

6.2 Adsorption Isotherms and Models 125

6.2.1 Langmuir Model 125

6.2.2 Freundlich Model 127

6.2.3 Temkin Model 128

6.2.4 Dubinin–Radushkevich Model 128

6.2.5 Hybrid Isotherm Models 129

6.3 Adsorption Kinetics and Models 130

6.3.1 Rate-Limiting Process and Kinetic Models 130

6.3.2 Pseudo-Kinetic Models 131

6.3.3 Elovich Model 132

6.3.4 Internal Diffusion Models 133

6.3.5 Homogeneous Surface Diffusion Model 133

6.4 Nanomaterial-Based Adsorbents 134

6.4.1 Overview of Adsorbents 134

6.4.1.1 Biochar 135

6.4.1.2 Activated Carbon 135

6.4.1.3 Ion Exchange Resins 137

6.4.1.4 Zeolite 137

6.4.2 Nanoparticle Adsorbents 138

6.4.3 Nanoparticle-Enabled Sand Filters 139

6.4.4 Nanocomposite Adsorbents 140

6.4.5 3D Gel Adsorbents 142

References 143

7 Nanoparticles in Water: Characterization 149

7.1 Sediments, Colloids, and Nanoparticles 149

7.1.1 Sediments 150

7.1.2 Colloids 150

7.1.3 Nanoparticles 151

7.2 Particles and Water Quality 152

7.2.1 Waterborne Pathogens 152

7.2.2 Engineered Nanoparticles 153

7.3 Analytical Methods for Nanoparticles in Water 154

7.3.1 Direct Separation 155

7.3.2 Visualization 157

7.3.3 Invisible Spectra 160

7.3.4 Other Methods 161

References 162

8 Nanoparticles in Water: Stability 165

8.1 Particle Aggregation 165

8.2 DLVO Theory 167

8.3 DLVO Model of CNTs 170

8.3.1 A Pristine SWNT and an Isotropic Planar Surface 171

8.3.2 A Surface-Modified SWNT and a Charged Isotropic Planar Surface 172

8.4 Nanoparticle Aggregation Kinetics 173

References 177

9 Nanoparticles in Water: Filtration 181

9.1 Particle Filtration 181

9.2 Classical Filtration Theory 183

9.3 Nanoparticle Filtration (Case Studies) 188

9.3.1 CNTs and Sand Columns 188

9.3.2 Biochar and Activated Carbon 191

References 193

10 Nanoparticles in Surface Runoff 195

10.1 Overview 195

10.2 Soil Erosion 197

10.2.1 Overview 197

10.2.2 Soil Erosion Models 198

10.2.3 Rainfall-Induced Nanoparticle Transport in Overland Flow 200

10.3 Vegetative Filter Strips 202

10.4 Single-Stem Efficiency Model 204

References 206

11 Subsurface Transport of Nanoparticles 211

11.1 Overview 211

11.2 Interaction Mechanisms 212

11.3 Influential Factors 214

11.3.1 Nanoparticle Properties 215

11.3.1.1 Particle Size 215

11.3.1.2 Surface Properties 216

11.3.1.3 Input Concentration 217

11.3.2 Medium Properties 218

11.3.2.1 Moisture Content 218

11.3.2.2 Medium Type 219

11.3.2.3 Grain Size 220

11.3.2.4 Medium Temperature 221

11.3.3 Flow Property 221

11.3.3.1 Flow Velocity and Direction 222

11.3.3.2 Ionic Strength 223

11.3.3.3 Solution pH 224

11.4 Transport Models 224

11.4.1 Homogeneous Porous Media 225

11.4.2 Heterogeneous Porous Media 225

References 228

Index 235