Master’s Course 2002 - 2004
Removal of Natural Organic Matters (NOMs) using Functional Magnetic-Impregnated Ion Exchange Resin (FMIEX) and its effects on membrane fouling Advisor:
Prof. Lee Kisay
Co-advisor: Prof. Lee Yonghun
Chu Xuan Quang Dept. of Environmental Engineering and Biotechnology
Presentation Outline
1. Objectives and Scope 2. General Background 3. Material and Methods 4. Results and Discussion 5. Summary
Objectives and Scope z
Objectives: – Evaluation of NOM removal effectiveness using developed FMIEX resin – Investigation of membrane fouling with FMIEX pretreated water
z
Scope: – Humic acids (HA) removal using FMIEX – Inorganic ions removal by FMIEX – Effects of FMIEX operating conditions on HA removal – Effects of FMIEX pretreatment on membrane fouling
General Background
:Why NOM removal is important? 9 NOM is present in all types of surface water 9 NOM causes unaesthetic color in drinking water 9 NOM is one of major foulants during membrane filtration processes 9 NOM is a major precursor for potentially harmful DBP formation 9 NOM should be removed during drinking water treatment
NOM and water quality issues
General background
:Mechanism of NOM removal by FMIEX Polystyrene Shell X X
X
Core
X
X
X
-NR3Cl; -COOH; -SO3H Activated Carbon
Ion Exchange
Magnetic component
Adsorption Interactions between the resin skeleton and the non-ionic core of the NOM (hyrophobic interaction) or through hydrogen bonds between NOM and the nitrogen atom of the amine functional group
Materials and Methods
:FMIEX and Jar Test Matrix
Polystyrene
Functionality
Quaternary ammonium
Counter ion
Chloride ion
Average particle size (µm) Specific surface area (m2/g)
219 0.0285
Average Exchange capacity (meq/g of resin)
0.21
Average Magnetite fraction (wt%)
4.4
Cross linkage (%)
30
Available pH
1 -14
Characteristics of FMIEX used
A jar tester system with FMIEX suspension, which is different from a packed column of conventional ion exchange resin
Materials and Methods
:Bases of analysis ¾ Dissolved Organic Carbon (DOC) Ö Operational definition: ≤ 0.45 µm; DOC ≥ 90 % of TOC Ö Typical: 3 – 4 mg/L; Range: 10 mg/L
¾ UV Absorbance @ 254 nm (UV254) Ö Sensitive to C=C and Aromatic-C bonds Ö Range: 0.050 – 0.200 cm-1
¾ Super ultraviolet absorbance (SUVA) Ö SUVA (L/mg-M) = 100 (cm/M) * [UVA (1/cm) / DOC (mg/L)] Ö Humic, Fulvic acids (highest SUVA); hydrophilic acids (low SUVA)
Materials and Methods
: Membrane used and Dead-end Filtration Unit Ultrafiltration protocols Pressure gauge
Data collection
Measuring J0 NOM flux decline test Nitrogen gas
Backwashing
Membrane Magnetic stirrer
Balance
Measuring J0,b
Characterizations of membrane used Membrane ID / Membrane type
PBHK / UF
Manufacturer
BiomaxTM, Millipore
Nominal pore size
100 k MWCO
Base material
Polyethersulfone (PES)
Hydrophilicity
Hydrophobic
Temp./Pressure limit
50oC/10psi
Chemical cleaning
Measuring J0,c
Results and Discussions
:Removal of Aldrich humic acid 9 UV254 removal ability 14
100 dosage=4g/L (UV254 removal percent) dosage=12g/L (UV254 removal percent)
12
dosage=4g/L (pH of finished water) dosage=8g/L (pH of finished water) dosage=12g/L (pH of finished water)
11
FMIEX dosage and contact time
10 9
60
8 7 6
40
5 4
pH
UV254 Removal_(%)
80
increased with increasing
13
dosage=8g/L (UV254 removal percent)
9 Most of the removal occurring within the first 60 min of contact time
3
20
2
9 A slight drops in the
1 0
0 0
20
40
60
80
100
120
140
160
180
Contact Time_(min.)
UV254 removal percent as a function of contact time for different FMIEX resin dosages (Aldrich HA concentration=10mg/L; pH=7; FMIEX : virgin particles; Mixing rate: 180rpm)
200
pH of the water were observed
Results and Discussions
:Removal of nitrate and sulfate ions 14 Phosphate removal (MAEX dosage = 4g/L) Phosphate removal (MAEX dosage = 8g/L) Phosphate removal (MAEX dosage = 12g/L) pH of finished water (MAEX dosage = 4g/L) pH of finished water (MAEX dosage = 8g/L) pH of finished water (MAEX dosage = 12g/L)
13 12
80
10 9
60
8 7 6
40
11 10 9
60
8 7 6
40
5
PO4
4 3
20
12
3-
5
13
4 3
20
2
2
1
0
1
0
0
20
40
60
80
100
120
140
160
180
0
0
200
0
20
40
60
Contact Time_(min.)
80
100
120
140
160
180
200
Contact Time_(min.)
Nitrate removal as a function of contact time for different FMIEX dosages (Nitrate concentration: 15mg/L as NO3--N; pH=6.7 ; FMIEX : virgin particles; Mixing rate: 180rpm)
Phosphate removal as a function of contact time for different FMIEX dosages (Phosphate concentration: 5mg/L as PO43--P; pH=7; FMIEX : virgin particles; Mixing rate: 180rpm)
Inorganic ion
Capacity
Nitrate
0.094 meqNO3--N/g resin
Phosphate
0.007 meqPO43--P/g resin
pH
11
pH
NO3 removal percent_(%)
80
100
14
Nitrate removal (MAEX dosage = 4g/L) Nitrate removal (MAEX dosage = 8g/L) Nitrate removal (MAEX dosage = 12g/L) pH of finished water (MAEX dosage = 4g/L) pH of finished water (MAEX dosage = 8g/L) pH of finished water (MAEX dosage = 12g/L)
removal percent_(%)
100
Results and Discussions
:FMIEX regeneration (1)
Procedure without pretreatment step:
- using 10% NaCl at pH ≈ 7 Procedure with pretreatment step:
¾ Pretreatment: - The AHA uptake resin were rinsed 3 times, alternating from 0.1N NaOH to 0.1N HCl - Interposingly, the resin were consecutively washed with DI water ¾ Regeneration:
- using 10% NaCl at pH=3
77.12 Recovery of the UV254 removal ability
¾ Regeneration:
100 80
59.51
60 40 20 0
without pretreatment
with pretreatment
Regeneration NOM uptake strategy: - Raw water: AHA (conc.=10mg/L; pH=7) - FMIEX dosage: 8g/L - Contact time: 60 min. - Mixing rate: 180 rpm
Results and Discussions
:FMIEX resin regeneration (2)
Regeneration using 10%NaCl regenerant for 10min. for 5min. for 15min.
100
% Removal
80
9 Uptake nitrate or phosphate by FMIEX resin is a reversible ion exchange reaction 9 Easy to change from nitrate or phosphate to chloride ions under the high regenerant ionic strength and chloride concentration
60
40
20 Nitrate Removal percent Phosphate Removal percent 0 virgin 1
2
3 4 5 6 7 8 9 10 11 12 13 14 15 Number of Regenerated Resin Reuse
9 Reason: the inorganic ions had only ion exchange mechanism
Results and Discussions
:Preparation of FMIEX resin 14
100
50
UV254 removal Color removal
pH value Turbidity
12
40
80
pH
6
20
% Removal
30
8
Turbidity_(NTU)
10 60
40
4 10
20
2 0 0.25
0
0
100
Jar test was conducted with:
UV254 value of water containing 10mg/L Aldrich HA
80
0.15
Color unit of water containing 10mg/L Aldrich HA
60
(conc. = 5mg/L; pH = 6.3)
- Contact time: 30 min. - Mixing rate: 180 rpm 10
40
0.05
20
5
0
0
0
5
10
15
20
FMIEX resin dosage_(g/L)
Water quality after 60 min. contact with different FMIEX dosages
25
- FMIEX dosage: 12g/L
15
0.10
0.00
- Raw water: SRHA
20
Turbidity_(NTU)
0.20
Color_(Co-Pt unit)
UV254_(cm-1)
UVabs @254nm Color unit
Virgin particles
Prepared particles
FMIEX resin used
Preparation variables for FMIEX resin
Results and Discussions
:Effects of contact time on FMIEX process 100
9 Reduction of UV254
14 13
UV254 removal pH value of finished water
would be used to
12
80
11
determine appropriate
9 60
8 7 6
40
5 4
pH value
% Removal
10
contact time 9 SRHA exchanges by FIMEX faster than AHA
3
20
2 1 0
0 0
20
40
60
80
100
120
140
160
180
200
220
Contact Time_ (min.)
UV254 removal percent as a function of contact time
(Suwannee River Humic Acid; concentration=5mg/L; pH=6.3; FMIEX : prepared particles; dosage = 8g/L; Mixing rate: 180rpm)
9 Contact time required to remove most of HA is only around 30 min.
Results and Discussions
:Effect of pH on FMIEX process 9 The HA removal by FMIEX
100 UV254 removal
resin depend on pH
DOC removal 80
lower pH: - where more positively
% Removal
9 Ion exchange were better at 60
40
charge species of resin are present - where negative charge on
20
0 4
HA is less (present under neutral form is major)
6
8
10
pH value
Effect of pH on HA removal (Suwannee River Humic Acid; concentration=5mg/L; FMIEX : prepared particles; dosage = 12g/L; Mixing rate: 180rpm)
Results and Discussions
:Appropriate FMIEX dosage 100 UV254 removal DOC removal
% Removal
80
60
40
20
0 0
4
8
12
16
20
FMIEX resin dosage_(g/L)
Impact of FMIEX resin dosage on HA removal (Suwannee River Humic Acid; concentration=5mg/L; pH=6.32 FMIEX : prepared particles; Mixing rate: 180rpm)
24
Results and Discussions
:Flux decline test results (effect of pH) 1.00
0.95
J/Jo
0.90
0.85 TWP4: UV254=0.029cm-1; pH=3.88 TWP6: UV254=0.073cm-1; pH=4.82
0.80
TWP8: UV254=0.087cm-1; pH=6.78 TWP10: UV254=0.096cm-1; pH=6.98
0.75 0
20
40
60
80
100
120
140
Permeate volume_(mL)
Flux decline test results on FMIEX treated water with different pH (Filtration with permeate flux around 450 LMH; TWP4, TWP6, TWP8, TWP10 are SRHA treated waters at pH=4, pH=6, pH=8, pH=10, respectively; FMIEX : prepared particles; FMIEX dosage= 12g/L; Mixing rate: 180rpm)
Results and Discussions
:Flux decline test results (effect of dosage) 1.00
0.95
J/Jo
0.90
0.85
Water without FMIEX pretreatment FMIEX pretreated water with dosage=12g/L FMIEX pretreated water with dosage=16g/L FMIEX pretreated water with dosage=20g/L
0.80
0.75 0
20
40
60
80
100
120
140
Permeate volume_(mL)
Flux decline test results on FMIEX treated water with different FMIEX dosage (Filtration with permeate flux around 450 LMH; Feeds are FMIEX pretreated waters; pH=6.3; FMIEX : prepared particles; Mixing rate: 180rpm)
Results and Discussions
:Water quality before and after FMIEX pretreatment Procedure
UV254 (cm-1)
Raw water
0.147
UV254 (cm-1) % removed DOC (mg/L)
2.529
DOC % removed
FMIEX dosage=12g/L
FMIEX dosage=16g/L
FMIEX dosage=20g/L
FMIEX
FMIEX + UF
FMIEX
FMIEX + UF
FMIEX
FMIEX + UF
0.067
0.031
0.041
0.019
0.029
0.012
54.42
78.91
72.11
87.07
80.27
91.84
1.605
1.205
1.242
1.076
1.174
0.875
36.54
52.35
50.89
57.45
53.58
65.40
SUVA (m-1mg-1L)
5.813
4.174
2.57
3.301
1.77
2.470
1.37
Color (Co-Pt unit)
63
30
21
21
12
18
3
52.38
66.67
66.67
80.95
71.43
95.24
Color %removed
Results and Discussions :Resistance components (different pH)
2.5e+5
intrinsic membrane resistance (Rm) reversible fouling resistance (Rr)
Resistance value_(1/cm)
2.0e+5
irreversible fouling resistance (Rir)
1.5e+5
1.0e+5
5.0e+4
0.0
WOT1
TWP4
TWP6
TWP8
TWP10
Feeds
Resistance components of UF membrane after filtration of FMIEX treated water with different pH
(TWP4, TWP6, TWP8, TWP10 are SRHA treated waters at pH=4, pH=6, pH=8, pH=10, respectively; FMIEX resin: prepared particles; FMIEX dosage= 12g/L; Mixing rate: 180rpm; WOT1 is raw water without FMIEX pretreatment)
Results and Discussions :Resistance components (different dosage)
Percentage of resistance components (%)
100
80
60
40
20
0 WOT2
TWD_12 TWD_16 Feeds
TWD_20
irrevesible fouling resistance chemically reversible resistance hydraulically reversible resistance intrinsic membrane resistance
Resistance components of UF membrane after FMIEX treated water with different FMIEX dosage
(TWD12, TWD16, TWD20 are SRHA treated waters with FMIEX dosage = 12g/L, 16 g/L, 20 g/L, respectively; pH=6.3; FMIEX resin: prepared particles; Mixing rate: 180rpm; WOT2 is SRHA raw water without FMIEX pretreatment)
Summary
The process using the novel FMIEX material has been shown to be very effective for removal of both, commercial humic acid (Aldrich) and Suwannee river humic acid (IHSS).
The FMIEX pretreatment dramatically reduced the rate of membrane fouling through the removal of humic acid. Hydrophobic fraction of humic acid with high aromaticity level, which has been known to be the major foulants during membrane filtration, were removed by the FMIEX.
The process using the new FMIEX material has been shown to be very effective for the NOM removal. The FMIEX pretreatment can be combined with membrane filtration technology for innovative drinking water treatment.
Thanks for your attention …
