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
7-*
Resins
Properties
Capacity
Proton exchange capacity (PEC)
7-*
Resins
Charge of the exchange ion must be neutralized
Z=3 must bind with 3 proton exchanging groups
Organic Exchange Resins
7-*
7-*
7-*
7-*
Range of distances between sites
Environments
Sorption based resins
Sorbs organics from aqueous solutions
Can be used to make functionalized exchangers
7-*
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
7-*
7-*
7-*
7-*
7-*
7-*
7-*
7-*
7-*
7-*
7-*
7-*
7-*
High loading
Limited breakthrough
Silicatitanates
Reprocessing
Transmutation
size and ligand
Prefer solid-liquid extraction
7-*
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
7-*
HO
OH
n
OH
OH
n
OH
OH
N
n
m
OH
x
Resorcinol Formaldehyde Resin
Catechol Formaldehyde Resin
Moisture regain
Ion exchange capacity
7-*
% 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
7-*
pH 14, Na, Cs, K, Al, V, As
7-*
7-*
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
7-*
Eu/La separation possible
D