Table Of ContentUltrafine Bubbles
Ultrafine Bubbles
edited by
Koichi Terasaka | Kyuichi Yasui
Wataru Kanematsu | Nobuhiro Aya
Published by
Jenny Stanford Publishing Pte. Ltd.
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Ultrafine Bubbles
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ISBN 978-981-4877-59-6 (Hardcover)
ISBN 978-1-003-14195-2 (eBook)
DOI: 10.1201/9781003141952
Contents
Preface
1. Hi story o f Ultrafine Bubbles xii1i
Akira Yabe
1.1 Characteristics of Ultrafine Bubbles,
Microbubbles, and Fine Bubbles 2
1.2 History of Microbubble Applications 2
1.2.1 Froth Flotation 2
1.2.2 Fine Bubbles for Ultrasonic Imaging
inside Body 3
1.2.3 Purification of Contaminated Water 3
1.2.4 Enhancement of Growth of Oysters,
Scallops, and Pearls 3
1.3 Historical Background of Ultrafine Bubbles 3
1.3.1 History of Academic Researches of Fine
Bubbles in Two-Phase Flow 3
1.3.2 Ultrapure Water Production System 4
1.4 Various Challenges for Characteristic
Clarification and Possible Application of
Ultrafine Bubbles 5
1.4.1 First Measurement of Ultrafine
Bubbles in Water 6
1.4.2 Cleaning Effect of Ultrafine Bubbles
for Minute Particle Contamination on
Plate 6
1.4.3 Shrinking Microbubbles and Ozone
Microbubbles 7
1.4.4 Transport of Solar Cell Wafers,
Volume Reduction of Jellyfish
Disposal, Vegetable Cultivation, and
Purification of Soil 7
1.4.5 Cleaning of Toilets in Expressway
Service Stations and Cleaning of Salt-
Stained Bridges 8
vi Contents
1.4.6 Cleaning and Sanitizing of Vegetables,
Enhancement of Vegetable Growth,
Promotion of Seed Germination 9
1.5 Systematic Scope of Historically Challenged
Application Fields and Historical Progress
Relating to Two Major Discussion Points by
Academic Viewpoints 9
1.5.1 Systematic Scope of Historically
Challenged Application Fields 9
1.5.2 Two Major Discussion Points of
Ultrafine Bubbles 11
1.5.2.1 Evidence on the existence of
ultrafine bubbles 11
1.5.2.2 Hypothesis for the
mechanism explaining the
long-time existence of
ultrafine bubbles in water 12
2. 1In.6tr oducCtoionnc ltuos iEoxnp eriments 1127
Koichi Terasaka
2.1 Introduction 18
2.2 Characteristics of Fine Bubbles 20
2.2.1 Rising Velocity and Brownian Motion
Velocity 21
2.2.2 Brown Movement Velocity of Ultrafine
Bubble 22
2.2.3 Friction Coefficient of Microbubble Flow 23
2.2.4 Specific Surface Area of Fine Bubbles 24
2.2.5 Self-Pressurization Effect of
Microbubbles 25
2.2.6 Microbubble Shrinkage 26
2.2.7 Surface Potential Characteristics of
Microbubbles 26
2.3 Generators of Fine Bubbles 27
2.3.1 Generators of Microbubbles 27
2.3.2 Microbubble Generation Technology 28
2.3.2.1 Swirling liquid flow type 29
2.3.2.2 Static mixer type 31
Contents vii
2.3.2.3 Mechanical shear flow type 33
2.3.2.4 Porous membrane type 33
2.3.2.5 Ejector type 36
2.3.2.6 Venturi type 37
2.3.2.7 Pressurized dissolution type 38
2.3.2.8 Heated oozing type 43
2.3.2.9 Mixed steam condensation
type 46
2.3.2.10 Others 48
2.3.3 Generators of Ultrafine Bubbles 48
2.3.4 Ultrafine Bubble Generation Technology 48
2.3.4.1 Pressurized dissolution type 49
2.3.4.2 Swirling liquid flow type 50
2.3.4.3 Static mixer type 51
2.3.4.4 Microporous membrane type
with surfactant addition 53
2.3.4.5 Ultrasonic irradiation 54
2.3.4.6 Strong shaking 55
2.4 Measurement of Ultrafine Bubbles 55
2.4.1 Size and Number Concentration 56
2.4.1.1 Particle tracking analysis 56
2.4.1.2 Dynamic light scattering 59
2.4.1.3 Laser diffraction and
scattering method 60
2.4.1.4 Coulter method 62
2.4.1.5 Quick-freezing replica method 64
2.4.1.6 Resonant mass measurement 65
3. Micro- a2n.d4 .U2 ltraZfeintae PBoutbebnlteisa lO bserved by 67
Transmission Electron Microscopy Using Quick-Freeze
Replica Technique 73
Kazunori Kawasaki
3.1 TEM Observation of MBs by Quick-Freeze
Replica Technique 74
3.2 TEM Observation of UFBs by Quick-Freeze
Replica Technique 81
3.3 Conclusion 85
viii Contents
4. Real UFB Sample Measurements: A Few Cases 87
Akinari Sonoda
4.1 Introduction 88
4.2 Ultrafine Bubble Monitor 89
4.2.1 Polystyrene Standard Particle 89
4.2.2 UFB Water Preparation by Agitational
Mixing Type Generator 91
4.2.3 UFB Water with Contamination 92
4.3 Measurement of UFB Using qNano 93
4.3.1 UFB Water Provided by Keio University 94
4.3.2 UFB Water Provided by Osaka
University 97
4.3.3 Commercially Available UFB Water 98
4.3.4 UFB Water to Irrigate Lettuce at Plant
Factory 99
4.4 Human Safety Test of Ozone UFB Water 100
4.4.1 Preparation of Ozone UFB Water 100
4.4.2 In vitro Skin Irritation Test 102
4.5 Conclusion 104
4.6 Appendix 104
4.6.1 Appendix A: UFB Obtained from
Keio University 104
4.6.2 Appendix B: UFB Obtained from
5. Theory of UltrafOinsea kBau bUbnlievse rsity 110069
Kyuichi Yasui
5.1 Introduction 109
5.2 Stability 110
5.2.1 Reason for Skepticism 110
5.2.2 Electrostatic Repulsion Model 113
5.2.3 Skin Model 115
5.2.4 Particle Crevice Model 116
5.2.5 “Armored” Bubble Model 116
5.2.6 Many-Body Model 117
5.2.7 Dynamic Equilibrium Model 118
5.3 Radical Formation 124
5.3.1 Experimental Results 124
Contents ix
5.3.2 Radical Formation during Cavitation 126
5.3.3 Radical Formation in a Dissolving
Bubble 135
5.3.4 Radical Formation after Stopping
Cavitation 141
5.4 Surface Tension 141
5.4.1 Experimental Results 141
5.4.2 Theoretical Study 142
6. 5St.5u dy ofC Uonltcralufisnioen B ubble Stabilization by Organic 146
Material Adhesion 155
Kou Sugano, Yuichi Miyoshi, and Sachiko Inazato
6.1 Introduction 156
6.2 Model of Stabilization Mechanism 156
6.3 Experimental Method 157
6.4 Results 161
6.4.1 UFB Generation Number Dependency 161
6.4.2 Effect of Addition of Organic Material
on UFB Concentration 164
6.4.3 UFB Analysis by TEM and Resonant
Mass Measurement 170
6.5 Consideration on UFB Stabilization
Mechanism 175
7. 6Cl.6ea ningC ownitchlu Uslitorna fine Bubble Water 117769
Koichi Terasaka
7.1 Introduction 179
7.2 Interfacial Energy 180
7.2.1 Surface Tension and Interfacial
Tension 181
7.2.2 Wettability and Contact Angle 182
7.2.3 Free Energy Change of Adhesion and
Desorption of Dirt 184
7.3 Fine Bubble Cleaning 185
7.3.1 Microbubble Cleaning 186
7.3.2 Ultrafine Bubble Cleaning 187
