1 IER Fundamentals

The Dow Chemical Company

About Ion Exchange

Marc Slagt Technical Support Specialist EMEA

Ion Exchange Fundamentals

I. INTRODUCTION

1.What is ion exchange? 2.Resins

1.Structure 2.Matrix 3.Functionality 4.Particle size

3.The system 4.Exchange reactions 5.Ion exchange process

6.Safety and Awareness

1. What is ion exchange? The mechanism

Na+

Cl-

Drinking water (water + ions)

resin

OH-

H+ resin

Cl-

Na+ + H2O IEX

RO

pressure membrane

H2O

Na+ + Cl-

chemicals

H

H H

H H

H

H

H

H

H

H H

H H H H

H H

H

H

H

H

H H

H

H

H H H

H

H H H

H

H

H

H H

H H

H

H

H

H H

H H

H

H

H

H

H

H

H

H H

H

H

H

H H

H

H

FUNCTIONAL GROUP

CARBON CHAINS NETWORK

SOLVENT (WATER) IN THE POROSITY

1. What is ion exchange

1. What is ion exchange

Na+

Cl-

Drinking water (water + ions)

Static RESIN

bed

Na+

Cl- H2O

The IER System

2. Resins What are ion exchange resins?

A. Chemical structure

B. Matrix

C. Functionality

CH=CH2

Styrene

SO3-H+

2. Resins: Chemical structure Polystyrene structure

CH CH2 CH CH2 CH CH2 CH CH2

CH=CH2

Styrene


2. Resins: Chemical structure Styrene Divinylbenzene (DVB) Copolymer



CH=CH2 CH=CH2

CH=CH2

Divinylbenzene Styrene

Cross linkage

2. Resins: DVB cross linkage

Total capacity Selectivity Physical stability Chemical stability

Water retention Swelling Kinetics Regenerability/Operating capacity Organic desorption ability

IF % DVB

2. Resins : Acrylic structure

+

+

Same polymerisation as WAC !

Dimethylaminopropylamine

Amberlite IRA67

WBA

Polymerisation

Amidation

CH2 CH CH CH

COOCH3 COOCH3 COOCH3

CH2 CH2 C

H CH2

COOCH3

CH3OH

NHCH2CH2CH2N CH3

CH3

CH2 CH

COCH3 O

NH2CH2CH2CH2N CH3

CH3

CH2 CH

C O

Divinylbenzene

Styrene

+

Styrene-DVB copolymer

SO3-H+

Strong Acid Cation Resin

Polymerization / catalyst (I)

Sulfonating acid / swelling

(II)

2. Resins: Cation manufacture

Divinylbenzene

Styrene

+

Styrene-DVB copolymer

Strong Base Anion Resin

ClCH2OCH3 (II)

CH2Cl

CH2N+(CH3)2R Cl-

Polymerization /catalyst (I)

:N(CH3)2R (III)

2. Resins: Anion manufacture

R = CH3 (Type 1) R = CH2-CH2-OH (Type 2) R = 0 (WBA)

2. Resins : matrix Gel

Pores

Cross-linking is evenly distributed in the matrix

Pseudo-crystalline structure Pores = mesh of the matrix Natural porosity Even pore size (a few ) Gel resin is transparent

2. Resins : matrix Macroporosity

Macropore

Macropore

Macropore

Artificial porosity is created with a porogen or phase extender

The porogen doesn't participate in the polymerisation

It just takes room in the system It is washed away once the

polymerisation is complete It leaves voids in the structure =

macropores Macroporous resins are opaque

Cation Exchange Resins Weak Acid Strong Acid

Anion Exchange Resins Weak base Strong Base

Type 1 Type 2 Acrylic

special chemical groups

2. Resin: Functionality a lot of choice..

Strong Acid Cation (SAC) Exchange Resin

SO3- H+

SO3-

2.Resins: functionality Cation Exchange Resin

High operating capacity High chemical efficiency

C O

O- H+

Weak Acid Cation Exchange Resin

Removes all cations Removes hardness in ratio to alkalinity

N: CH3

CH3

HCl Removes Free Mineral Acids Only: HCl, H2SO4, HNO3, etc.

High Operating Capacity smaller vessels High Regeneration Efficiency less chemicals Good for organics removal less fouling

2.Resins: Functionality Anion Exchange Resin Weak Base (WBA)

Type 1 Anion Exchange Resin

2.Resins: Functionality Anion Exchange Resin Strong Base

Type 2 Anion Exchange Resin

High Chemical Stability High Silica Removal

N+ CH3 CH3

OH- CH3

N+ CH3

CH3

CH2 CH2 OH

OH-

High Operating Capacity/regeneration Lower Silica Removal than Type 1! Sensitive to temperature

Removes all anions

2.Resins: functionality acrylic anion

C

CH CH2

CH

O NHCH2CH2N CH3

CH3

CH3Cl

or (CH3)2SO4 C

CH CH2

CH

O NHCH2CH2N+-CH3 CH3

CH3 Cl-

Amberlite IRA67 Amberlite IRA458 Cl

Quaternisation

WBA SBA

DRYING SIEVING

SULFONATION HYDRATION

CHLOROMETHYLATION AMINATION

WASHING DEWATERING PACKAGING

CO-POLYMERIZATION

2.Manufacturing steps

Cation Anion

MONOMERS STYRENE

DIVINYLBENZENE CATALYSTS

WATER + STABILISER

CONTROL TEMPERATURE

STIRRING

HEATING

(POROGENIC CHEM.)

SUSPENSION MEDIUM

2.Stirred reactor

Chamber

Suspension solution

Monomer feed

Orifice plate

Motor

Copolymer exit

Piston

2. DOW uniform resin JETTING

2. Resins: Particle size distribution

Conventional (Gaussian) resins typically 0.3-1.2 mm bead size range.

UPS resins typically ~0.6 mm (600 m).

Information source: DOWEX Ion Exchange Resins, The Advantages of Uniform Particle Sized Ion Exchange Resins, March 2006

Trademark of The Dow Chemical Company ("Dow") or an affiliated company of Dow

2. Resins: Particle size uniformity

screen size passing 90% Uniformity Coefficient (UC) = ------------------------------- screen size passing 40%

0 200 400 600 800 1000 1200 1400

Bead Size, microns

Volu

me

Perc

ent 40%

90%

0 200 400 600 800 1000 1200 1400

Bead Size, microns

Vo

lum

e P

erc

en

t 40%

90%

UC = 1010 m / 650 m = 1.6 UC = 580 m / 540 m = 1.07

2. Resins: Particle size

A = Effective Size = 90% volume of beads retained B = Harmonic mean diameter= 50% volume of beads passed

Bead diameter

Vol. (%)

0 A

90%

B

50%

3. The System

Application (softening, demin, polishing, boron, nitrate, scavenging, etc)

Vessels + operational logic

Distribution system

Piping + valves

Regeneration station + chemical storage

Waste discharge / Neutralization facilities

Feed water and product water distribution

PLC control system

4. Ion exchange reactions Definition of Ion Exchange

Ion exchange is the reversible exchange of ions between a solid and a liquid in which there is no substantial change in the structure of the solid.

Exhaustion Regeneration

Cation resin bead

H+

H+

H+

H+

H+

H+

H+

Na+ Na+

Na+ Cation resin bead

H+

H+

H+

H+

H+

H+

H+

Na+

Na+

Na+

Resin selectivity creates chromatographic exhaustion:

loosely held ions travel quickly

tightly held ions travel slowly

moving ionic wave fronts are established

Ca2+

Mg2+

Na+

H+

4. Ion exchange reactions selectivity

Selectivity Increases with Charge Al3+ > Ca2+ > Na+

SO42- > Cl

Selectivity Increases with Atomic Number Ca2+ > Mg2+

Br- > Cl- > F-

4. Ion exchange reactions Selectivity

ION VALENCE DEGREE OF CROSS-LINKAGE 4% DVB 8% DVB 16% DVB MONOVALENT IONS H 1.0 1.0 1.0 Li 0.90 0.85 0.7 Na 1.3 1.5 1.9 NH4 1.6 1.95 2.5 K 1.75 2.5 3.3 Cs 2.0 2.7 3.4 Ag 6.0 7.6 17.0 DIVALENT IONS Mn 2.2 2.35 2.7 Mg 2.4 2.5 2.8 Zn 2.6 2.7 3.0 Cu 2.7 2.9 3.6 Ca 3.4 3.9 5.8 Pb 5.4 7.5 14.5 Ba 6.15 8.7 16.5

4. Ion exchange reactions Cationic selectivity

KHNa > 1 means that the affinity for Na is higher than that for H

TYPE 1 TYPE 2 OH 1.0 1.0 FLUORIDE 1.6 0.3 ACETATE 3.2 0.5 BICARBONATE 6.0 1.2 CHLORIDE 22 2.3 BISULFITE 27 3 NITRATE 65 8 CITRATE 220 23

ANION RESINS SELECTIVITY COEFFICIENT

4. Ion exchange reactions Selectivity

Neutralize bases: R-H + Na+OH R-Na+ + H2O High capacity for alkaline earth metals associated with alkalinity: 2R-H + Ca2+(HCO3)2 R2-Ca2+ + 2CO2 + 2H2O Limited capacity for the alkali metals with alkalinity: 2R-H + Na+2CO3 2R-Na+ + CO2 + H2O No significant salt splitting occurs with neutral salts, due to equilibrium with HCl: R-H + Na+Cl R-Na+ + HCl However, if resin is neutral (Na form), softening can be performed: 2R-Na + Ca2+Cl2 R2-Ca2+ + 2NaCl

4. Ion exchange reactions Weak acid cations

WACs is responsible for capacity & efficiency

RFR

End of regeneration In service

Feed water ions: Na+ K+ Mg2+ Ca2+ Cl- SO42- NO3- HCO3- HSiO3- pH = 7

Weak acid cation

Outlet ions: Na+ K+ Cl- SO42- NO3- CO2 HSiO3- pH ~ 5

4. Ion exchange reactions

Ca2+

2H+

Splits salts/neutralize bases: R-H + Na+Cl R-Na+ + HCl 2R-H + Ca2+(HCO3)2 R2-Ca2+ + 2CO2 + 2H2O In the neutral (sodium) form, they can be used for softening: 2R-Na + Ca2+Cl2 R2-Ca + Na+Cl

4. Ion exchange reactions Strong acid cations

SACs is responsible for water quality

RFR


Strong acid cation Outlet ions: Na+ leakage H+ Cl- SO42- NO3- CO2 HSiO3-


Inlet ions: Na+ K+ (Leakage) Cl- SO42- NO3- CO2 (HCO3-) HSiO3-

= pH Na+

H+

Weak base anion resins are capable of adsorbing strong acids onto the electron pair on the free amine group:

R-N: + H+Cl- R-N: HCl

4. Ion exchange reactions Weak base anions

WBA is responsible for capacity & efficiency

RFR


Weak base anion

Outlet ions: Na+ leakage

CO2 HSiO3-


Inlet ions: Na+ leakage H+ Cl- SO42- NO3- CO2 HSiO3-

Cl-

OH-

Splits salts/neutralize acids: R-OH + NaCl- R-Cl- + NaOH 2R-OH + H2SO4 R2-SO4 + 2H2O R-OH + HSiO3- R-HSiO3 + OH-

In the neutral (chloride) form, they can be used for nitrate or anionic metal complex removal:

R-Cl + NaNO3 R-NO3 + NaCl

4. Ion exchange reactions Strong base anions

SBA is responsible for water quality

RFR


Strong base anion

Outlet ions: Na+ leakage OH-


Inlet ions: Na+ leakage CO2 HSiO3-

OH- HSiO3-

= pH

INDUCES A CHANGE IN VOLUME

STRONG ACID CATION RESIN STRONG BASE ANION RESIN GEL Na to H + 7% Cl to OH + 15-20% MACRO Na to H + 5% Cl to OH + 10-12%

WEAK ACID CATION RESIN WEAK BASE ANION RESIN MACRO H to Ca + 15% FB to HCl + 20-35% MACRO H to Na + 60% GEL H to Na + 90%

4. Ion exchange reactions Change of resin volume change in ionic form

5. Ion exchange process Batch process

Fresh bed regeneration exhaustion

HCl / H2SO4 = Cation resin NaCl = Cation softening NaOH = Anion resin NaCl = Anion organic scavenger

exhaustion

Common regenerants:

5. Ion exchange process Production = loading of ions

Exhausted resin

Conductivity Leakage

Operating capacity 75% of total

Regenerated resin

Reaction zone

Start End

Total capacity 100%

Eluate (spent regenerant)

Regenerant (upflow)

Feed water

Clean polishing zone

Before regeneration

After regeneration

5. Ion exchange process Regeneration = taking ions off the resin

Reverse flow regeneration

UPCORE Amberpack

Regenerant (downflow)

Eluate (spent regenerant)

Residual close to column outlet

Feed water

Before regeneration

After regeneration

5. Ion exchange process Regeneration = taking ions off the resin

Co flow regeneration

5. Ion exchange process

Co-flow regeneration: The badly regenerated bottom layers cause ionic leakage

End of regeneration

CFR

In service

NaNa

NaNa

Na

H H

HH

H

H

HH

H

Na Na

Na

010

20

30

40

50

60

0 20 40 60 80 100 120

Conductivity profile

co-flow counter flow

5. Ion exchange process Quality during production

5. Ion exchange process Regeneration brings quality and quantity

1. Amount of chemicals per liter resin (g/l) 2. Temperature of the regeneration (anion) 3. Contact time 4. Concentration of the injected chemicals 5. Bed Lift 6. Displacement of chemicals

Amount of regenerant : Quantity The regeneration method : Quality

5. Ion exchange process Equivalent per liter

Ion Exchange Process All parameters are calculated as charge

100 mgCa2+/liter = 100 / (40/2) (atomic mass / valence) = 5 meq/l

1 liter cation resin (H) = 1000 meq OperatingCapacity

1000 meq OC / 5 = 200 liter of water to treat until exhaustion

110% stoichiometry of HCl to regenerate: 1,1 * 1000 = 1100 meq HCl * 0,0365 = 40 gram 100% HCl / liter resin

5. Ion exchange process Generating eq/l capacity with regeneration

The amount of chemicals per volume of resin makes a certain amount of the total volume capacity available (as equivalents per liter) = operating

capacity. For that you need 1 eq HCl for 1 eq cations + excess as stoichiometry to the ionic load.

TVC

OC 160% (log scale)

5. Ion exchange process Typicals on capacity

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

Typi

cal c

apac

ity (e

q/l)

Total capacity (area A+B)Operating capacity (area A)

Comparison of Operating and Total Capacity

Weak cation

Strong cation

Weak anion

Stronganion type 1

Stronganion type 2

Additional support

More information is available on the web:

http://www.dowwaterandprocess.com/

- Product info - Technical information

- Operational data like Tech Facts

- Troubleshooting guidance

- Literature

- The Answer center

Design and evalaution software : IXCalc / CADIX introduction


Resins are active chemical products.

Concentrated chemicals are used in the process

Resin spill on the floor is dangerous

Sample connections and measurement connections can be filled with chemicals

Chemicals do not always have odor or color

Be alert and protect yourself.

Thank You

About Ion ExchangeIon Exchange Fundamentals1. What is ion exchange?The mechanism1. What is ion exchange1. What is ion exchange2. ResinsWhat are ion exchange resins?2. Resins: Chemical structure Polystyrene structure2. Resins: Chemical structureStyrene Divinylbenzene (DVB) Copolymer2. Resins: DVB cross linkage2. Resins : Acrylic structureSlide Number 11Slide Number 12Slide Number 13Slide Number 14Slide Number 15Slide Number 16Slide Number 17Slide Number 182.Resins: functionality acrylic anionSlide Number 20Slide Number 21Slide Number 22Slide Number 232. Resins: Particle size uniformity2. Resins: Particle size3. The System4. Ion exchange reactions Definition of Ion ExchangeSlide Number 28Slide Number 29Slide Number 30ANION RESINS SELECTIVITY COEFFICIENTSlide Number 324. Ion exchange reactionsSlide Number 344. Ion exchange reactionsSlide Number 364. Ion exchange reactionsSlide Number 384. Ion exchange reactionsSlide Number 40Slide Number 415. Ion exchange process Production = loading of ions5. Ion exchange process Regeneration = taking ions off the resin5. Ion exchange process Regeneration = taking ions off the resin5. Ion exchange processSlide Number 46Slide Number 47Slide Number 48Slide Number 495. Ion exchange process Typicals on capacity Additional support6.Safety and Awareness6.Safety and AwarenessSlide Number 54

1 IER Fundamentals

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