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Ion Exchange
Michelle CostenaroDepartment of Ecology
Toxics Reduction Engineer425.649.7143
[email protected]
Chuck Babb Greg AllanHytek Finishing Co. Advanced Chemical
Technologies
Chemist Consultant253.872.7160 425.868.7804
[email protected] [email protected]
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Ion Exchange
Chemical Reaction reversible chemical reaction insoluble solid
(resin) and a solution
(wastewater) ions are interchanged
Used only on dilute solutions
What is it?
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Ion Exchange
Cationic Resin exchange H+ for other positively charged ions
Replaces: nickel, copper, chromes (Cr III),
cadmium, lead Weak Acid Resin
Requires less acid to regenerate Strong Acid Resin
Achieves lower cation concentration
How does it work?
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Ion Exchange
Anionic Resin exchange OH- for other negatively charged ions
Replaces: chromates (Cr VI), sulfate, cyanide,
carbonate Weak Base Resin
Requires less base regenerate Strong Base Resin
Achieves lower anion concentration
How does it work?
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Ion Exchange
Anionic Resin Column Cationic Resin Column Series of Anionic and
Cationic Resin
Columns Mixture of Anionic and Cationic Resin in
one Column Metal-Specific Resin Column
How does it work?
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Ion Exchange
Factors Affecting Resin Choice Contamination ions pH
Resin Fouling Oil and grease Total suspended solids > 10 ppm
Oxidants
How does it work?
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Ion ExchangeCation - Ion Exchange Example
H+ H+
H+
H+
H+H+
H+
A+
H+
A+
A+
A+H+
H+
A+
A+
A+
A+
A+
A+
A+
H+ - Hydrogen Ion
A+ - Metal Cation Being Removed
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Ion ExchangeContinuous Flow Process Setup
H+ - Hydrogen Ion
A+ - Metal Cation Being Removed
ProcessLine
Regenerate
TreatedWater
Regenerate Regenerate
TreatedWater
Regenerate
TreatedWater
ProcessLine
ProcessLine
ProcessLine
TreatedWater
Regenerate
TreatedWater
ProcessLine
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Ion Exchange
Pretreatment for Rinse Water
Chemical Recovery from Rinse Water
Remove Contaminants from Plating Bath
Wastewater Treatment
Where can it be used?
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Ion Exchange
Why? Cleaner rinse will result in better quality of
products Water reuse potential less discharge
Possible reduction in regulatory oversight
What do you need? Both cation and anion columns
Pretreatment for Rinse Water
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Ion Exchange
Why Concentrate chemicals from the rinse water to
replenish process bath Concentrate chemicals for recovery
What do you need? Only one type of ion exchange column
cation or anion
Chemical Recovery from Rinse Water
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Ion Exchange
Why? Remove impurities from drag-in, corrosion,
reduced or decomposed bath chemicals, etc. Extend bath life
Reduce the amount disposed bath water Chemical recovery
What do you need? Only one type of ion exchange column Resin
type depends on the bath
Remove contaminants from plating bath
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Ion Exchange
Initial: Why?
Chemical recovery What do you need?
Depends on types of chemical (probably only cation)
Final: Why?
To meet discharge permit What do you need?
Depends on types of contaminants (probably only cation)
Wastewater Treatment
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Ion Exchange
When? Resin loading Pressure Water testing
How? Backflow of acid or base
On-site Off-site
Resin Regeneration
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FinalRinse
DragoutTank
ProcessBath
CationIon
ExchangeColumn
CationIon
ExchangeColumn
AnionIon
ExchangeColumn
AnionIon
ExchangeColumn
PretreatmentCarbon Filtration
Membrane FiltrationpH Adjust
DI Water
Chemical Recovery from Rinse BathsWastewater Treatment
Evaporation
Acid NaOH
Electrowinning
ElectrowinningReuse orDisposal
Metal: Recycled
Treatment / Disposal
Electrolyte:Treatment/Disposal
DI / City Water
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FinalRinse
DragoutTank
ProcessTank
CationIon
ExchangeColumn
CationIon
ExchangeColumn
PretreatmentCarbon Filtration
Membrane FiltrationpH Adjust
Treatment / Disposal
Rinse Water RecyclingChemical Recovery from Rinse Baths
Evaporation
Acid
Electrowinning
ElectrowinningReuse orDisposal
Metal: RecycledElectrolyte:Treatment/Disposal
DI / City Water
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CationIon
ExchangeColumn
CationIon
ExchangeColumn
AnionIon
ExchangeColumn
AnionIon
ExchangeColumn
PretreatmentCarbon Filtration
Membrane FiltrationpH Adjust
Dirty Rinse Water
Acid NaOH
Treated Effluentto POTW
SolidsDewatering / Disposal
Treatment
Process
Clean Rinse Water
Rinse Water RecyclingChemical Recovery from Rinse Baths
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Ion Exchange
Factors Treatment requirements Resin use Regenerant used and
efficiency
Cost
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Ion Exchange
Payback Factors Operation cost of ion exchange Cost / volume of
process bath disposal
Estimated Total Capital Investment
Cost
$85,00030$60,000 - $70,00020$30,000 - $40,00010
$GPMCostFlow Rate
Source: TechSolve at www.iams.org
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Ion Exchange
Examples Chromium Cyanide
Treatment Ion Specific Ion Exchange Columns Cyanide Destruct
Batch or Off-Site Treatment
Segregated Rinses
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Ion Exchange
What Waste Streams? Process Baths Regenerant Special Metal
Rinses (ie: Chrome)
Example Treatment Batch Treatment Off-Site Treatment
Other Treatment
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Ion Exchange
Good Employee Techniques Dragout Reduction Rinsing Techniques
Bath Maintenance
Dilute Rinse Baths Only System Design Resin Regeneration
Summary
