PRELIMINARY DATA
BACKGROUND
Increased water demands & diminishing high quality water
sources lead to the use of previously underutilized technologies
MOTIVATIONS
CONCLUSIONS
• The presence of calcium in solution negatively
impacts the performance of ion exchange for both
bicarbonate-form and chloride-form. The presence
of magnesium also impacts performance.
• Chloride-form ion exchange isn’t impacted as
greatly by the presence of divalent cations as
bicarbonate-form.
• Bicarbonate-form anion exchange is greatly
impacted by the presence of divalent cations. The
presence of magnesium has the most profound and
immediate impact.
• Yes, inorganic fouling does impact bicarbonate-form
ion exchange but subsequent work aims to
determine exactly how so the process can be
optimized
FUTURE WORK • Complete additional regeneration cycles and
perform regeneration cycles on waters containing
no cations, and waters containing Co2+.
• Investigate the biological fouling of bicarbonate-
form biological fouling
• Innovative regeneration by CO2(g) sparging and
optimization
Figure 1: Preliminary results showing bicarbonate-form resin
performance is on par with chloride-form in absence of divalent
cations. Synthetic water contained Santa Fe River NOM,
nitrate, sulfate, bicarbonate, and chloride. Figure adapted from
Rokicki and Boyer 20112.
Calcium
Magnesium
Figure 3: DOC removal by chloride-form ion exchange resins over
multiple regeneration cycles in the presence of calcium. Figure 4: DOC removal by bicarbonate-form ion exchange resins over
multiple regeneration cycles in the presence of calcium.
Species pKsp1
MgCO3 3.68
CaCO3 8.01
CdCO3 11.3
Figure 5: DOC removal by chloride-form ion exchange resins over
multiple regeneration cycles in the presence of magnesium.
Figure 6: DOC removal by bicarbonate-form ion exchange resins over
multiple regeneration cycles in the presence of magnesium.
ACKNOWLEDGEMENTS
I would like to thank Dr. Treavor
Boyer for all his support and
guidance. I would also like to
thank the Boyer research team
for all their help and support in
and out of the laboratory.
References 1Knovel, 2008. Knovel Critical Tables (2nd Edition). (2008).
Knovel. http://www.knovel.com/web/portal/browse/
display ?_EXT_KNOVEL_DISPLAY_bookid=761 2Rokicki, C.A., Boyer, T.H., 2011. Bicarbonate-form anion
exchange: Affinity, regeneration, and stoichiometry.
Water Research 45, 1329 -1337. 3Walker K.M., Boyer, T.H., 2011. Long-term performance of
bicarbonate-form anion exchange: Removal of dissolved
organic matter and bromide from the St. Johns River,
FL, USA.. Water Research 45 (9), 2875-2886.
RESULTS
• Ion exchange (IEX) may be a treatment
solution for certain waters with higher
levels of natural organic matter (NOM):
IEX ResinNOM
NOM
NOM
NOM
HCO3-
HCO3-
HCO3-
HCO3-
Cl-
Cl-
Cl-
Cl-
Cl-
Cl-
Cl-
Cl-
Cl-
Cl-
Cl-
IEX Resin
NOM
NOMNOM
NOM
HCO3-
HCO3-
HCO3-HCO3
-
Cl-
Cl-Cl-
Cl-
Cl-
Cl-
Cl-
Cl-
Cl-
Cl-
Cl-
• However, brine associated with chloride-
form resin limits the potential applications
of IEX. Bicarbonate-form would generate
easier to dispose of regenerant and would
prevent increase of salinity of local waters.
• It is unknown how the presence of
bicarbonate within the resin structure will
react with divalent cations:
Table 1: Carbonate mineral
solubility products. Table adapted
from Knovel 20081
IEX Resin
HCO3-
HCO3-
X2+
X2+
H+
H+HCO3-
Brine disposal is a major concern,
much like RO concentrate, it often
impedes the implementation of this
technology.
DOES INORGANIC FOULING LIMIT THE USES OF
ECOLOGICALLY FRIENDLY ANION EXCHANGE? Christopher A. Rokicki, and Treavor H. Boyer1
Department of Environmental Engineering Sciences, University of Florida, Gainesville, FL [email protected] ~ (352)846-3351 ~ http://www.ees.ufl.edu/homepp/boyer/
Figure 2: SEM images of chloride- and bicarbonate-form resin
after 14 regenerations showing inorganic fouling of bicarbonate-
form. Figure adapted from Walker and Boyer 20113.
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
r0 r1 r2 r3
% D
OC
re
mo
va
l
regeneration#
M-Cl
M-HCO3
0%
10%
20%
30%
40%
50%
0 50 100
% D
OC
rem
oval
time (min)
r0
r1
r2
r3
chloride-form chloride-form
0%
10%
20%
30%
40%
50%
0 50 100
% D
OC
rem
oval
time (min)
r0
r1
r2
r3
bicarbonate-form
0%
10%
20%
30%
40%
50%
0 50 100
% D
OC
rem
oval
time (min)
r0
r1
r2
r3
bicarbonate-form
0%
10%
20%
30%
40%
50%
0 50 100
% D
OC
rem
oval
time (min)
r0
r1
r2
r3
chloride-form
A) Changing water supply and quality
B) Advanced treatment processes needed to meet new
requirements from changes in A and demands from D
C) Waste generated in chloride-form anion exchange
needs treatment
D) Increasing water demands impact demands in B and
generates waste to be treated
E) Effluent contains trace contaminants from C
(including high TDS) and D that remain post treatment