Basic Principles of Membrane Technolog

Transcription

1 Basic Principles of Membrane Technolog by Marcel Mulder Center for Membrane Science and Technology, University oftwente, Enschede, The Netherlands ff KLUWER ACADEMIC PUBLISHERS DORDRECHT / BOSTON / LONDON

2 CONTENTS 1. 1 Separation processes to membrane processes 7 I. 3 History 9 I 4 Definition of a membrane Membrane processes Solved problems 18 I Materials and material properties Polymers Stereoisomerism Chain flexibility Molecular weight Chain interactions State of the polymer Effect of polymeric strueture on Tg Glass transition temperature depression Thermal and chemical stability Mechanical properties Elastomers Thermoplastic elastomers Polyelectrolytes Polymer blends Membrane polymers Porous membranes Nonporous membranes Inorganic membranes Thermal stability Chemical stability Mechanical stability Biological membranes Synthetic biological membranes Solved problems

3 I Preparation of synthetic membranes I I. 2 Preparation of synthetic membranes 72 I. 3 Phase inversion membranes 75 I. 3.1 Preparation by evaporation 76 I. 3.2 Precipitation.from the vapour phase 76 I. 3.3 Precipitation by controlled evaporation 76 I. 3.4 Thermal precipitation 76 I. 3.5 Immersion precipitation 77 I. 4 Preparation techniques for immersion precipitation 77 I. 4.1 Fiat membranes 77 I. 4.2 Tubulär membranes 78 I. 5 Preparation techniques for composite membranes 81 I. 5.1 Interfacial polymerisation 82 I. 5.2 Dip-coating 83 I. 5.3 Plasma polymerisation 86 I. 5.4 Modification of homogeneous dense membranes 87 I. 6 Phase Separation in polymer Systems 89 I I Thermodynamics 89 I. 6.2 Demixing processes 99 I Binary mixtures 99 I Ternary Systems 102 I. 6.3 Crystallisation 104 I. 6.4 Gelation 106 I. 6.5 Vitrification 108 I. 6.6 Thermal precipitation 109 I. 6.7 Immersion precipitation 110 I. 6.8 Diffusional aspects 114 I. 6.9 Mechanism of membrane formation 117 I. 7 Influence of various parameters on membrane morphology 123 I. 7.1 Choice of solvent-nonsolvent System 123 I. 7.2 Choice of the polymer 129 I. 7.3 Polymer concentration 130 I. 7.4 Composition of the coagulation bath 132 I. 7.5 Composition of the casting Solution 133 I. 7.6 Preparation of porous membranes - summary 134 I. 7.7 Formation of integrally skinned membranes 135 I Dry-wet phase Separation process 136 I Wet-phase Separation process 137 I. 7.8 Formation of macrovoids 138 I. 8 Inorganic membranes 141 I. 8.1 Thesol-gelprocess 141 I. 8.2 Membrane modification 144 I. 8.3 Zeolite membranes 144 I. 8.4 Glass membranes 146 I. 8.5 Dense membranes 147 I. 9 Solved problems 147

4 I. 10 I Characterisation of membranes IV.. 1 IV..2 IV..3 IV..4 IV.5 IV.6 IV.7 IV.8 \ Membrane characterisation Characterisation of porous membranes IV. 3.1 IV IV IV IV IV IV IV. 3.2 IV IV IV IV IV Microfiltration Electron microscopy Atomic force microscopy Bubble-point method Bubble-point with gas permeation Mercury intrusion method Permeability method Ultrafiltration Gas adsorption-desorption Thermoporometry Permporometry Liquid displacement Solute rejection measurements Characterisation of ionic membranes IV. 4.1 Electrokinetic phenomena IV. 4.2 Electro-osmosis Characterisation of nonporous membranes IV. 5.1 Permeability methods IV. 5.2 Physical methods IV DCS/DTA methods IV Density measurements IV Density gradient column IV Density determination by the Archimedes principle IV Wide-angle X-ray diffraction (WAXD) IV. 5.3 Plasma etching IV. 5.4 Surface analysis methods Solved problems Transport in membranes V V. 2 Driving forces 212 V.3 Nonequilibrium thermodynamics 214 V. 4 Transport through porous membranes 224 V. 4.1 Transport of gases through porous membranes 225 V Knudsenflow 226 V. 4.2 Friction model 228

5 Transport V. 5.1 V V V V.5.2 V V V V V V. 5.3 through nonporous membranes Transport in ideal Systems Determination of the diffusion coefficient Determination of the solubility coefficient Effect of temperature on the permeability coefficient Interactive Systems Free volume theory Clustering Solubility of liquid mixtures Transport of Single liquids Transport of liquid mixtures Effect of crystallinity Transport through membranes. A unified approach V.6.1 Reverse osmosis V.6.2 Dialysis V.6.3 Gas permeation V. 6.4 Pervaporation Transport in ion-exchange membranes Solved problems VI Membrane processes Osmosis Pressure driven membrane processes VI. 3.1 VI. 3.2 VI Microfiltration Membranes for microfiltration VI Industrial applications 292 VI Summary of microfiltration 292 VI. 3.3 Ultrafiltration 293 VI Membranes for Ultrafiltration 294 VI VI Summary of Ultrafiltration 296 VI. 3.4 Reverse osmosis and nanofiltration 297 VI Membranes for reverse osmosis and nanofiltration 299 VI VI Summary of nanofiltration 302 VI Summary of reverse osmosis 303 VI. 3.5 Pressure retarded osmosis 303 VI Summary of pressure retarded osmosis 305 VI. 3.6 Piezodialysis 305 VI Summary of piezodialysis 306 VI. 4 Concentration as driving force 307 VI VI. 4.2 Gas Separation 308

6 VI. 4.2 VI VI VI VI VI VI VI VI. 4.3 VI VI VI VI VI. 4.4 VI VI VI VI VI VI VI VI. 4.5 VI VI VI VI VI. 4.6 VI VI Gas Separation Gas Separation in porous membranes Gas Separation in nonporous membranes Aspects of Separation Joule - Thomson effect Membranes for gas Separation Summary of gas Separation Pervaporation Aspects of Separation Membranes for pervaporation Summary of pervaporation Carrier mediated transport Liquid membranes Aspects of Separation Liquid membrane development Choice of the organic solvent Choice of the carrier Summary of carrier mediated transport Dialysis Transport Membranes Summary of dialysis Diffusion dialysis Summary of diffusion dialysis Thermally driven membrane processes VI. 5.1 VI. 5.2 VI VI VI VI Membrane contactors VI. 6.1 VI VI. 6.2 VI VI. 6.3 VI. 6.4 VI. 6.5 Electncally VI. 7.1 VI. 7.2 VI VI Membrane distillation Process parameters Membranes Summary of membrane distillation Gas-liquid contactor Liquid-liquid contactors Nonporous membrane contactors Summary of membrane contactors Thermo-osmosis driven membrane processes Electrodialysis Process parameters Membranes for electrodialysis

7 VI VI Separation of amino acids 387 VI Summary of electrodialysis 388 VI 7.3 Membrane electrolysis 388 VI The 'chlor-alkali' process 389 VI Bipolar membranes 390 VI 7.4 Fuelcells 391 VI 7.5 Electrolytic regeneration of mixed-bed ion-exchange resin 393 VI. 8 Membrane reactors and membrane bioreactors 394 VI. 8.1 Membrane reactors 395 VI. 8.2 Non-selective membrane reactor 396 VI. 8.3 Membrane reactor in liquid phase reactions 398 VI. 8.4 Membrane bioreactors 400 VI. 9 Solved problems 400 VI VI V Polarisation phenomena and fouling V V. 2 Concentration Polarisation 418 V. 2.1 Concentration profiles 423 V. 3 Turbulence Promoters 424 V. 4 Pressure drop 426 V. 5 Characteristic flux behaviour in pressure driven membrane Operations 427 V. 6 Gel layer model 429 V. 7 Osmotic pressure model 431 V. 8 Boundary layer resistance model 436 V. 9 Concentration Polarisation in diffusive membrane separaüons 440 V. 10 Concentration Polarisation in electrodialysis 442 V. 11 Temperature polarisation 444 V. 12 Membrane fouling 447 V Fouling tests in reverse osmosis 451 V. 13 Methods to reduce fouling 453 V. 14 Compaction 456 V. 15 Solved problems 456 V V VI Module and process design VI VI VI VIH vin VI l Plate-and-frame model Spiral wound module Tubulär module Capillary module Hollow fiber module 465 '

8 VI. 7 VI. 8 VI. 9 VI. 10 VI. 11 VI. 12 VI. 13 VI. 14 VI. 15 VI. 16 VI. 17 VI. 18 VI. 19 VI. 20 VI. 21 VI. 22 VI. 23 Comparison of the module configurations System design Cross-flow Operations Hybrid dead-end/cross flow System Cascade Operations Some examples of System design VI Ultrapure water VI.12.2 Recovery of organic vapours VI Desalination of seawater VI Dehydration ofethanol VI.12.5 Economics Process parameters Reverse osmosis Diafiltration Gas Separation and vapour permeation VI.16.1 Gas Separation under complete mixing conditions VI.16.2 Gas Separation under cross-flow conditions Pervaporation VI.17.1 Complete mixing in pervaporation VI.17.2 Cross-flow in pervaporation Pervaporation Dialysis Energy requirements VI * Pressure driven processes VI Partial pressure driven processes VI Concentration driven processes Solved problems Appendix 1 Appendix 2 Answers to i exercises: solved problems Answers to i exercises: unsolved problems List of symbols Index 557