lect 7 ion exchange.ppt

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7-1 Ion Exchange Resins General resin information Functional Groups Synthesis Types Structure Resin Data Kinetics Thermodynamics Distribution Radiation effects Ion Specific Resins

Transcript of lect 7 ion exchange.ppt

Ion Exchange ResinsResins
Organic or inorganic polymer used to exchange cations or anions from a solution phase
General Structure
Functional group for complexing anion or cation
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Resins
Properties
Capacity
Proton exchange capacity (PEC)
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Resins
Charge of the exchange ion must be neutralized
Z=3 must bind with 3 proton exchanging groups
Organic Exchange Resins
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Range of distances between sites
Environments
Sorption based resins
Sorbs organics from aqueous solutions
Can be used to make functionalized exchangers
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Sn, Th, U
Theoretical plates used to estimate reactions
Swelling
The stability constants for metal ions can be found
Based on molality (equivalents/kg solute)
Ratio (neutralized equivalents)
Thermodynamic concentration based upon amount of sites available
Constants can be evaluated for resins
Need to determine site concentration
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High loading
Limited breakthrough
Silicatitanates
Reprocessing
Transmutation
size and ligand
Prefer solid-liquid extraction
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Use metal ion as template
Ease of Synthesis
Flexibility of applications
Different functional groups
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
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HO
OH
n
OH
OH
n
OH
OH
N
n
m
OH
x
Resorcinol Formaldehyde Resin
Catechol Formaldehyde Resin
Moisture regain
Ion exchange capacity
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% meq/g %
8-hydroxyquinoline increase IEC
0.05 g resin
Distribution coefficient
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
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pH 14, Na, Cs, K, Al, V, As
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Sheet1
Resin
10 mL solution
0.05 g resin
millimolar Am concentration
≈ 95% of Am removed by CQF, RQF
243Am removed from resin by HNO3
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Eu/La separation possible
D