Dynamics of Adsorption at Liquid Interfaces (eBook)

Cover 1
Contents 8
Preface 18
Chapter 1. Introduction 20
1.1. Surfaces, surface tension and surface phenomena 21
1.2. Surface chemistry of surfactants and basic adsorption phenomena 24
1.3. Adsorption dynamics and dynamic adsorption layers. Qualitative approach 30
1.4. Some surface phenomena 32
1.5. Organisation of the book 45
1.6. References 46
Chapter 2. Thermodynamics and macro-kinetics of adsorption 49
2.1. Definition of liquid interfaces 49
2.2. Models of the surface of water 53
2.3. General principles of equilibrium surface thermodynamics 56
2.4. Adsorption at liquid/fluid interfaces 62
2.5. Treatment of the Langmuir adsorption isotherm as introduction to adsorption dynamics 66
2.6. Adsorption isotherm for single and mixed surfactant systems 67
2.7. Macro-kinetic aspects of Langmuir's theory and its application to adsorption dynamics 69
2.8. Charged liquid interfaces 71
2.9. Summary 80
2.10. References 81
Chapter 3. Surface phenomena, surface rheology and relaxations processes at liquid interfaces 87
3.1. Relaxations and chemical reactions 88
3.2. Stress-strain relationships - general description 91
3.3. Brief Introduction Into Surface Rheology 94
3.4. Surface rheology and adsorption dynamics in drainage processes of thin liquid films 102
3.5. Surface rheology and stability of foams and emulsions 106
3.6. Surface waves 110
3.7. Summary 113
3.8. References 115
Chapter 4. The dynamics of adsorption at liquid interfaces 119
4.1. General idea of adsorption kinetics 120
4.2. Theoretical models of diffusion-controlled adsorption kinetics 122
4.3. Diffusion-controlled adsorption of surfactant mixtures 130
4.4. Kinetic-controlled models 132
4.5. Models with time dependent interfacial area 134
4.6. Adsorption kinetics of surfactants at liquid/liquid interfaces 141
4.7. Adsorption kinetics from micellar solutions 143
4.8. Adsorption process at the surface of laminar flowing liquid films 147
4.9. Adsorption kinetics of polymers 149
4.10. Asymptotic solutions 151
4.11. Summary 153
4.12. References 155
Chapter 5. Experimental technique to study adsorption kinetics 159
5.1. Characterisation of the purity of surfactants and solvents 161
5.2. Drop volume technique 172
5.3. Maximum bubble pressure technique 176
5.4. Pendent drop technique 182
5.5. Growing drop methods 185
5.6. The oscillating jet method 187
5.7. The inclined plate technique 189
5.8. Description of other dynamic methods for interfacial studies 190
5.9. Experimental results from studies of surfactants at liquid interfaces 195
5.10. Experimental studies of the adsorption dynamics of biopolymers at liquid interfaces 207
5.11. Summary 211
5.12. References 213
Chapter 6. Relaxation studies at liquid interfaces 221
6.1. Introduction to interfacial relaxation studies 221
6.2. Interfacial relaxation techniques 226
6.3. Interfacial relaxation methods 235
6.4. Experimental results of relaxation studies 242
6.5 Summary 252
6.6. References 253
Chapter 7. Effect of surfactant charge on the dynamics of adsorption 257
7.1. Introduction 257
7.2. The retardation of the steady transport of adsorbing ions through the diffuse part of double layer 261
7.3. The manifestation of electrostatic retardation in transient adsorption processes 268
7.4. Dynamics of adsorption at harmonically disturbed surfaces 270
7.5. Stages of adsorption kinetics of ionics under the condition of convective diffusion 274
7.6. Adsorption kinetics model, taking into account the electrostatic retardation and a specific adsorption barrier 275
7.7. The problem of ion adsorption models 277
7.8. Electrostatic retardation in macro-ion adsorption 279
7.9. A numeric solution to the problem 280
7.10. Experimental investigations of adsorption kinetics of ionic surfactants 283
7.11. Summary 285
7.12. References 286
Chapter 8. Dynamic adsorption layer of buoyant bubbles. Diffusion-controlled transport of nonionic surfactants 288
8.1. Basic problems 288
8.2. Dynamic adsorption layer under condition of uniform surface retardation 300
8.3. Theory of dynamic adsorption layer of bubble (drop) at Re< <
8.4. Theory of dynamic adsorption and diffusion boundary layers of a bubble with Pe> >
8.5. Hypothesis of incomplete retardation of a bubble surface at Re < 1 and presence of a dynamic adsorption layer
8.6. Theory of dynamic adsorption layer of a bubble and retardation of its surface at large Reynolds numbers 319
8.7. The rear stagnant region of a buoyant bubble 327
8.8. Total amount of surfactant at mobile bubble surfaces 332
8.9. Summary 338
8.10. References 340
Chapter 9. Dynamic adsorption layers of surfactants at the surface of buoyant bubbles. Kinetic-controlled surfactant transport to and from bubble surfaces 342
9.1. Dynamic adsorption layers of nonionic surfactants 342
9.2. Dynamic adsorption layers of ionic surfactants 347
9.3 Structure of rear stagnant cap of a bubble rising in solution of ionic surfactant at Re< <
9.4. Conditions of realization of regimes of ionic surfactant dynamic adsorption layer formation 352
9.5. The size of the stagnant cap of the bubble (droplet) using surfactants with a slow rate desorption 356
9.6. Summary 359
9.7. References 360
Chapter 10. Dynamic adsorption layer in microflotation 361
10.1 Mechanism of transfer of small particles to bubble surface 362
10.2. Effect of dynamic adsorption layer on the transport stage of the elementary flotation act 370
10.3. Investigation of microflotation kinetics as a method of DAL studies 384
10.4. Dynamic adsorption layer and optimisation of transport stage of flotation 388
10.5. Specific features of the mechanism involving attachment of small particles on the surface of a bubble 389
10.6. Influence of dynamic adsorption layer on attachment of small particles on bubble surface 403
10.7. Influence of dynamic adsorption layer on small particle detachment 404
10.8. Perfection of microflotation by governing dynamic adsorption layer 405
10.9. Effect of particle aggregation on elementary microflotation act and dynamic adsorption layer 406
10.10. Collision efficiency, bubble velocity and microflotation kinetics 408
10.11. Bubble coalescence and dynamic adsorption layer 408
10.12. Two-stage flotation of micron and submicron particles and dynamic adsorption layer 411
10.13. Selection and application of cationic surfactant in microflotation and dynamic adsorption layer 412
10.14. Negative effect of inertia forces on flotation of small particles. Generalisation of Sutherland's formula. Extension of limits of applicability of microflotation theory 414
10.15. Influence of dynamic adsorption layer on inertia forces in microflotation 422
10.16. Effect of hydrodynamic boundary layer on elementary act of microflotation and dynamic adsorption layer of bubbles 424
Chapter 11. Dynamic adsorption layer in flotation 441
11.1. Quasi-elastic collision 442
11.2. Inelastic collision 446
11.3. Prevention of particle deposition on bubble surface at T> Tt under the effect of centrifugal force
11.4. Particle reflection from a bubble surface 455
11.5. Prevention of particle deposition on bubble surface at angles .< .ocr due to joint action of particle reflection from a bubble surface and centrifugal forces
11.6. Estimation of collision efficiency 459
11.7. Kinetics of extension of three-phase contact 461
11.8. Attachment by collision. 463
11.9. Influence of dynamic adsorption layer on attachment by collision 469
11.10. Attachment by sliding at potential flow. The role of particle rebound and critical film thickness 471
11.11. Influence of dynamic adsorption layer on attachment process by sliding 478
11.12. Investigations of collision and attachment stages of both microflotation and flotation 480
11.13. Influence of dynamic adsorption layer on detachment 486
11.14. Summary 487
11.15. References 490
Chapter 12. Non-equilibrium surface forces caused by dynamic adsorption layers and their relevance in film stability and flotation 492
12.1. The effect of the dynamic adsorption layer on coagulation 492
12.2. The influence of the ionic adsorption layer upon coagulation processes 494
12.3. The liquid interlayer stabilization by dynamic adsorption layers in elementary flotation act 495
12.4. Estimation of effectiveness of particles capture considering liquid interlayer stabilisation by dynamic adsorption layers 501
12.5. Non-equilibrium surface forces of diffusion-electrical nature in flotation 503
12.6. Summary 505
12.7. References 506
Appendices 507
Appendix 2A: General principles of the degrees of freedom of interfaces 507
Appendix 2B: Discussion of Further Adsorption Isotherms 508
2B.1. Htickel-Cassel Isotherm 508
2B.2. The Volmer Adsorption Isotherm 511
2B.3. The Butler-Volmer-Equation 511
Appendix 2C: Non-Equilibrium Surface Thermodynamics 512
Appendix 2D: Thermodynamics of Thin Liquid Films 515
Appendix 3A: Sound Propagation in Liquid/Fluid Disperse systems and Chemical Reaction 520
Appendix 3B: Dynamic Contact Angles 525
Appendix 3C: Marangoni-instabilities and dissipative structures 527
Appendix 3D: Lateral Transport Phenomena 532
Appendix 4A: Numerical solution of the integral equation of Ward and Tordai 533
Appendix 4B: Numerical solution of the function exp(x2)erfc(x) 534
Appendix 4C: Finite difference scheme to solve the initial and boundary condition problem of a diffusion controlled adsorption model 537
Appendix 4D: Finite difference scheme to solve the initial and boundary condition problem of a diffusion controlled adsorption model for a two component surfactant system 540
Appendix 4E: Application of the Laplace transform to solve the diffusion-controlled adsorption kinetics model 540
Appendix 4F: Polynomial parameters of the collocation solution Eq. (4.25) after Ziller & Miller (1986)
Appendix 5A: Correction Factors after Wilkinson (1972) in the form rcap/a as a function of r.V -1/3 544
Appendix 5B: Density and viscosity of selected liquids 548
Appendix 5C: Surface tension of selected liquids and its interfacial tension to water 549
Appendix 5D: Isotherm parameters of selected surfactants 550
Appendix 5E: Mutual solubility of organic solvents and water 552
Appendix 5F: Numerical aAlgorithm to sSolve the Gauss-Laplace equation 552
Appendix 5G: Dynamic surface tensions in the sub-millisecond range 554
Appendix 6A: Application of system theory for the determination of interfacial tension Response functions to small interfacial area disturbances 556
Appendix 6B: Interfacial tension response functions ..(T) to harmonic and several types of transient area disturbances 556
Appendix 6C: Interfacial pressure response to area disturbances in presence of insoluble monolayers 559
Appendix 7A: The approximate integration of the differential equation of adsorption of multivalent ions 560
Appendix 8A: Small rear stagnant cap of bubble at high Reynolds numbers 563
Appendix 10A: Processes restricting water purification by microflotation, and prevention of bubble surface retardation 566
Appendix 10B: Role of r.s.c, in transport stage at different particle attachment mechanisms 567
Appendix 10C: Choice of hydrodynamic regime under production conditions. Decimicrone-size particle 568
Appendix 10D: New development in surface forces 570
Appendix 10E: Microflotation of submicron, micron and decimicron particles 576
10E.1. Micron and submicron particles. Air-dissolved flotation and microflotation 576
10E.2. Decimicron particles 577
Appendix 10F: Flotation with centimicron and millimeter bubbles 577
10F.1. The use of centimicron bubbles 577
10F.2. Use of millimeter bubbles 578
Appendix 10G: Flotation with bubbles between millimeter and centimicron 578
Appendix 10H: Possibility of microbubble capture from below, dynamic adsorption layer and possibility of decrease of surfactant consumption 579
Appendix 10I: Air-dissolved flotation and two-stage flotation 580
Appendix 10J: Industrial application of two-stage microflotation 580
Appendix 10K: Bubble polydispersity in two-stage flotation 581
Appendix 10L: Two-stage microflotation with particle aggregation 582
Appendix 10M: Comments on the role of boundary layer and centrifugal force as discussed by Mileva (1990) 583
10M1. Lift force 583
10M2. Reynolds numbers characterising the particle motion relative to the liquid 584
10M3. Lift force and centrifugal force 584
Appendix 11A: Correction of the calculation of centrifugal forces at St > St c
Appendix 11B: Analysis the theory by Schulze and co-worker on attachment by collision 585
List of Symbols 587
Subject Index 592