Page 23 - Fundamentals of Water Treatment Unit Processes : Physical, Chemical, and Biological

xxii Contents

Chapter 16 Ion-Exchange...................................................................................................................................................... 511
16.1 Description............................................................................................................................................... 511
16.1.1 Ion-Exchange In-a-Nutshell........................................................................................................ 511
16.1.1.1 Definitions................................................................................................................... 511
16.1.1.2 Process Description..................................................................................................... 511
16.1.1.3 Phases of Operation .................................................................................................... 511
16.1.2 History ........................................................................................................................................ 512
16.1.2.1 Science ........................................................................................................................ 512
16.1.3 Applications................................................................................................................................ 512
16.1.3.1 Municipal Use............................................................................................................. 512
16.1.3.2 Removals of Specific Ions.......................................................................................... 513
16.1.3.3 Deionization................................................................................................................ 513
16.1.4 Media.......................................................................................................................................... 513
16.1.4.1 Mineral Ion-Exchangers.............................................................................................. 513
16.1.4.2 Clays ........................................................................................................................... 513
16.1.4.3 Zeolites........................................................................................................................ 513
16.1.4.4 Synthetic Resins.......................................................................................................... 516
16.1.4.5 Aluminas..................................................................................................................... 519
16.2 Ion-Exchange Theory .............................................................................................................................. 520
16.2.1 Capacity of Media...................................................................................................................... 520
16.2.1.1 Expressions of Capacity ............................................................................................. 520
16.2.1.2 Upper Limit of Capacity............................................................................................. 520
16.2.2 Equilibria .................................................................................................................................... 521
16.2.2.1 General Reaction and Equilibrium Equations ............................................................ 521
16.2.2.2 Isotherm Expression of Equilibrium........................................................................... 521
16.2.2.3 Selectivity of Counterions .......................................................................................... 521
16.2.3 Kinetics....................................................................................................................................... 522
16.2.3.1 Rate-Determining Step................................................................................................ 522
16.2.3.2 Fick’s First Law .......................................................................................................... 522
16.3 Design...................................................................................................................................................... 523
16.3.1 Selection of Ion-Exchangers....................................................................................................... 523
16.3.1.1 Resins.......................................................................................................................... 523
16.3.1.2 Zeolites........................................................................................................................ 523
16.3.1.3 Range of Ion-Exchangers and Properties ................................................................... 523
16.3.2 System Design............................................................................................................................ 524
16.3.2.1 Pretreatment ................................................................................................................ 524
16.3.2.2 Reactor Cycle.............................................................................................................. 524
16.3.2.3 Regeneration ............................................................................................................... 525
16.3.3 Reactor Design ........................................................................................................................... 525
16.3.3.1 Summary of Design Data ........................................................................................... 525
16.3.3.2 Pilot Plant Studies....................................................................................................... 526
16.4 Operation ................................................................................................................................................. 526
16.4.1 Operating Cycle.......................................................................................................................... 527
16.4.1.1 Production................................................................................................................... 527
16.4.1.2 Regeneration ............................................................................................................... 527
16.4.1.3 Disposal....................................................................................................................... 527
16.5 Case Studies............................................................................................................................................. 527
16.5.1 Nitrate Removal at Glendale, Arizona....................................................................................... 527
Problems............................................................................................................................................................. 528
Acknowledgments .............................................................................................................................................. 529
Appendix 16.A: Ion-Exchange Conversions................................................................................................... 529
Glossary.............................................................................................................................................................. 532
References .......................................................................................................................................................... 537
Bibliography....................................................................................................................................................... 538