Ion exchange resins
Download
1 / 46

Ion Exchange Resins - PowerPoint PPT Presentation


  • 368 Views
  • Uploaded on

Ion Exchange Resins. General resin information Functional Groups Synthesis Types Structure Resin Data Kinetics Thermodynamics Distribution Radiation effects Ion Specific Resins. Ion Exchange Resins. Resins

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' Ion Exchange Resins' - kalia-park


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
Ion exchange resins
Ion Exchange Resins

  • General resin information

    • Functional Groups

    • Synthesis

    • Types

    • Structure

  • Resin Data

    • Kinetics

    • Thermodynamics

    • Distribution

  • Radiation effects

  • Ion Specific Resins


Ion exchange resins1
Ion Exchange Resins

  • Resins

    • Organic or inorganic polymer used to exchange cations or anions from a solution phase

  • General Structure

    • Polymer backbone not involved in bonding

    • Functional group for complexing anion or cation


Resins
Resins

  • Properties

    • Capacity

      • Amount of exchangeable ions per unit quantity of material

        • Proton exchange capacity (PEC)

    • Selectivity

      • Cation or anion exchange

        • Cations are positive ions

        • Anions are negative ions

      • Some selectivities within group

        • Distribution of metal ion can vary with solution


Resins1
Resins

  • Exchange proceeds on an equivalent basis

    • Charge of the exchange ion must be neutralized

      • Z=3 must bind with 3 proton exchanging groups

  • Organic Exchange Resins

    • Backbone

      • Cross linked polymer chain

        • Divinylbenzene, polystyrene

        • Cross linking limits swelling, restricts cavity size


Organic resins
Organic Resins

  • Functional group

    • Functionalize benzene

      • Sulfonated to produce cation exchanger

      • Chlorinated to produce anion exchanger


Resin synthesis
Resin Synthesis

HO

OH

HO

OH

NaOH, H

O

2

HCOH

n

resorcinol

OH

OH

OH

OH

NaOH, H

O

2

HCOH

n

catechol

a

a

a


Resins2
Resins

  • Structure

    • Randomness in crosslinking produces disordered structure

      • Range of distances between sites

      • Environments

        • Near organic backbone or mainly interacting with solution

          Sorption based resins

  • Organic with long carbon chains (XAD resins)

    • Sorbs organics from aqueous solutions

    • Can be used to make functionalized exchangers


Organic resin groups
Organic Resin groups

Linkage group

Cation exchange

Anion exchange

Chloride



Inorganic resins
Inorganic Resins

  • More formalized structures

    • Silicates (SiO4)

    • Alumina (AlO4)

      • Both tetrahedral

      • Can be combined

        • (Ca,Na)(Si4Al2O12).6H2O

      • Aluminosilicates

        • zeolite, montmorillonites

        • Cation exchangers

        • Can be synthesized

    • Zirconium, Tin- phosphate



Inorganic ion exchanger
Inorganic Ion Exchanger

  • Easy to synthesis

    • Metal salt with phosphate

    • Precipitate forms

      • Grind and sieve

  • Zr can be replaced by other tetravalent metals

    • Sn, Th, U


Kinetics
Kinetics

  • Diffusion controlled

    • Film diffusion

      • On surface of resin

    • Particle diffusion

      • Movement into resin

  • Rate is generally fast

  • Increase in crosslinking decrease rate

  • Theoretical plates used to estimate reactions

    Swelling

  • Solvation increases exchange

  • Greater swelling decreases selectivity


Selectivity
Selectivity

  • Distribution Coefficient

    • D=Ion per mass dry resin/Ion per volume

  • The stability constants for metal ions can be found

    • Based on molality (equivalents/kg solute)

    • Ratio (neutralized equivalents)

      • Equilibrium constants related to selectivity constants

  • Thermodynamic concentration based upon amount of sites available

    • Constants can be evaluated for resins

      • Need to determine site concentration


Radioactive considerations
Radioactive considerations

  • High selectivity

    • Cs from Na

  • Radiation effects

    • Not sensitive to radiation

      • Inorganics tend to be better than organics

  • High loading

    • Need to limit resin change

    • Limited breakthrough

  • Ease of change

    • Flushing with solution

  • Good waste form

    • Radioactive waste


Hanford tanks
Hanford Tanks

  • 177 Tanks

  • Each Tank 3,800,000 Liters

  • Three sections

    • Salt cake

    • Sludge

    • Supernatant

  • Interested in extracting Cs, Sr, Tc, and Actinides with

    • Silicatitanates

    • Resorcinol formaldehyde

    • CS-100 (synthetic zeolite)


Ion selective resins
Ion Selective Resins

  • Selected extraction of radionuclides

    • Cs for waste reduction

    • Am and Cm from lanthanides

      • Reprocessing

      • Transmutation

  • Separation based on differences in radii and ligand interaction

    • size and ligand

  • Prefer solid-liquid extraction

  • Metal ion used as template


Characteristics of resins
Characteristics of Resins

  • Ability to construct specific metal ion selectivity

    • Use metal ion as template

  • Ease of Synthesis

  • High degree of metal ion complexation

  • Flexibility of applications

  • Different functional groups

    • Phenol

    • Catechol

    • Resorcinol

    • 8-Hydroxyquinoline


Resin synthesis1
Resin Synthesis

  • Catechol-formaldehyde resin (CF)

  • Resorcinol-formaldehyde resin (RF)

  • Phenol-8-hydroxyquinoline formaldehyde resin (PQF)

  • Catechol-8-hydroxyquinoline formaldehyde resin (CQF)

  • Resorcinol-8-hydroxyquinoline formaldehyde resin (RQF)

    Resins analyzed by IR spectroscopy, moisture regain, and ion exchange capacity


OH

HO

OH

OH

n

n

Catechol Formaldehyde Resin

Resorcinol Formaldehyde Resin

OH

OH

OH

N

x

m

n

x = 0, Phenol-8-Hydroxyquinoline Formaldehyde Resin

x = 1, Catechol-8-Hydroxyquinoline Formaldehyde Resin

x = 1, Resorcinol-8-Hydroxyquinoline Formaldehyde Resin


Experimental
Experimental

  • IR spectroscopy

    • Resin characterization

      • OH, C=CAromatic, CH2 , CO

  • Moisture regain

    • 24 hour heating of 0.1 g at 100°C

  • Ion exchange capacity

    • Titration of 0.25g with 0.1 M NaOH


Moisture regain and iec
Moisture Regain and IEC

Resin Moisture IEC Theory IEC

% meq/g %

CF 20 8.6 55

RF 40 11.5 74

PQF 10 5.9 80

CQF 20 9.6 70

RQF 19 9.9 70

  • Phenolic resins have lower IEC

  • 8-hydroxyquinoline increase IEC


Experimental1
Experimental

  • Distribution studies

    • With H+ and Na+ forms

    • 0.05 g resin

    • 10 mL of 0.005-.1 M metal ion

    • Metal concentration determined by ICP-AES or radiochemically

    • Distribution coefficient

      Ci = initial concentration

      Cf = final solution concentration

      V= solution volume (mL)

      m = resin mass (g)



Distribution coefficients for group 1 elements
Distribution Coefficients for Group 1 elements.

All metal ions as hydroxides at 0.02 M, 5 mL solution, 25 mg resin, mixing time 5 hours

D (mL/g (dry) Selectivity

Resin Li Na K Rb Cs Cs/Na Cs/K

PF 10.5 0.01 8.0 13.0 79.8 7980 10

RF 93.9 59.4 71.9 85.2 229.5 3.9 3.2

CF 128.2 66.7 68.5 77.5 112.8 1.7 1.6


Cesium column studies with rf
Cesium Column Studies with RF

pH 14, Na, Cs, K, Al, V, As


Eu la competitive extraction
Eu/La Competitive Extraction

Distribution Coefficients, 2.5 mM Eu,La, pH 4

Resin La Eu Eu/La

CF 2.38x106 2.03x106 0.85

RF 2.59x106 2.18x106 0.84

PQF 64.4 400 6.21

CQF 98.1 672 6.85

RQF 78.4 817 9.91




Studies with 243 am
Studies with 243Am

  • Conditions similar to Eu studies

    • 10 mL solution

    • 0.05 g resin

      • RF, CF, PQF, RQF, CQF

    • millimolar Am concentration

  • Analysis by alpha scintillation

  • >99% of Am removed by CF, RF, PQF

  • ≈ 95% of Am removed by CQF, RQF

  • 243Am removed from resin by HNO3


Ion specific resins
Ion Specific Resins

  • Effective column separation possible

  • Phenol exhibits selectivity

  • Incorporation of 8-hydroxyquinoline leads to selectivity, but lower extraction

  • Eu/La separation possible

  • Possible to prepare ion specific resins for the actinides


ad