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Efficient Coacervate Extraction of Cationic Industrial Dye from Wastewater
Department of Chemical Engineering and Material Science Benjamin Valley • Benxin Jing • Y. Elaine Zhu
Background & MotivationsDye Industry:[1]
➢ Over 10,000 Different Dyes Used Industrially
➢ 7 x 105 Tons of Dye-Stuff Produced Annually
➢ ~10-50% of Dye Stuff Used For Textiles is
Discharged as WasteBlue Dogs Spotted in India Near Textile Plant!![2]
Current Treatment Methods:[3]
Method Advantages Disadvantages
Fentons
Reagent
Effective
decolourisation
Only for low
concentration
Activated
Carbon
Good removal
efficiency
Extremely
expensive!
UltrafiltrationEffective dye
removal
Multi-step
process, fouling
Our Approach:
➢ Coacervate Extraction[4] Liquid-Liquid Separation Process
✓ One-step method provides facile operation
✓ No membrane fabrication/casting required!
✓ Rapid phase-separation short processing time
Companies Marketing Dye
Removal Technology:
Polyampholyte Based Coacervation
Polyampholyte:
P((AMPS)x-co-(MAPTAC)y)
✓Tunable Net Charge
✓Perpendicular Backbone
AMPS
(-) MAPTAC
(+)
Randomly Alternating Charge Sequence!
Polyoxometalate (POM) Nanocluster:
Tungsten-12 Particle
• Li6[H2W12O40]
• Inorganic Polymer
• [W12O40]8-
• ~0.8nm Diameter
Salt:
Lithium Chloride
• 0.4M – 0.7M
• Adjusts Ionic
Strength of Solution
Polyampholyte – W12 Coacervate Complex Dye ExtractionCoacervate Phase Formation:
100% 120% 130%
x:y~50-50
x:y~45-55
38.3 g/L
Polyampholyte-W12
Complexes
200%
Net “Neutral”
Net Positive
CLiCl = 0.2M
CLiCl = 0.2M
CLiCl = 0.77M
0.01 0.1 1-10
-5
0
5
10
15
20
25
30
35
x:y=45:55
x:y=50:50
x:y=55:45
Ep
on
ten
tia
l (m
V)
Ionic Strength (M)
Electric Potential Measurement
Constant Polymer Weight Used For Extractions
Dye Extraction
𝐶𝑀𝐵 =𝐴𝑏𝑠663𝑛𝑚 − 0.0144
222.82
500 550 600 650 7000.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
Ab
sorb
an
ce
Wavelength (nm)
0.0001 g/L
0.0002 g/L
0.0004 g/L
0.0006 g/L
0.0008 g/L
0.001 g/L
0.002 g/L
0.004 g/L
0.006 g/L
0.008 g/L
0.01 g/L
0.02 g/L
UV-vis Spectra of Pure MB
0.000 0.002 0.004 0.006 0.008
0.0
0.5
1.0
1.5
2.0
Methylene Blue Calibration Curve
Absorb
ance (
663
nm
)
Concentration (g/L)
Abs = 222.82CMB
+ 0.0144
R2 = 0.9988
359.3 348.2 364.7 397.6
95
100%W12(50-50) 200%W12(50-50) 100%W12(45-55) 200%W12(45-55) GAC
0
50
100
150
200
250
300
350
400
450
qm
ax (
mg
/g)
Adsorbent
CMB = 0.2 g/LCLiCl = 0.4M
Coacervate Extraction
Granular
Activated
Carbon[5]
Methylene Blue (MB):
✓ Highly Stable Thiazine Dye
✓ Used in Medical, Textile, & Printing Industries
✓ Diameter ~ 1.0nm
0 50 100 150 200 250 300 350 400 450 500 550 600
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
qt (
mg/g
)
Time (seconds)
100% W12 50-50
200% W12 50-50
100% W12 45-55
200% W12 45-550
10
20
30
40
50
60
70
80
90
100
% D
ye
Rem
ove
d
Most Commercial Dyes Possess Toxic & Mutagenic Properties!
0.1 1 10 100 1000
0
50
100
150
200
250
300
350
100%W12 50-50
200%W12 50-50
100%W12 45-55
200%W12 45-55
qe (
mg
/g)
Ce (mg/L)
MB Adsorption Kinetics MB Adsorption Isotherms
𝑞𝑒 = 𝑞𝑚𝑎𝑥𝑘𝐿𝐶𝑒
1 + 𝑘𝐿𝐶𝑒
Conclusion✓Verified High Performance Adsorption Process, qmax= 397.6 mg/g
✓Faster and More Efficient Compared to Conventional Methods
✓Robust Method for Ionic Selective Wastewater Treatment
1. F. Chequer et al. Textile Dyes: Dying Process and Environmental Impact. INTECH 2013, 6, 151-176.2. S. Gibbens National Geographic 2017, Aug. 18.3. Robinson, T., McMullan, G., Marchant, R., & Nigam, P. Remediation of dyes in textile effluent: a critical review on current treatment
technologies with a proposed alternative. Bioresource Technology 2001,77, 247-255.4. Melnyk, A., Namiesnik, J., & Wolska, L. Theory and recent applications of coacervate-based extraction techniques. Trends in Analytical
Chemistry 2015,71, 282-292.5. Azizian, S.; Haerifar, M.; Bashiri, H. Adsorption of Methyl Violet onto Granular Activated
Carbon: Equilibrium, Kinetics and Modeling. Chem. Eng. J. 2009, 146, 36–41.6. Langmuir, I. The constitution and fundamental properties of solids and liquids. J. Am. Chem. Soc. 1916, 38, 2221–2295.
References
[6]
Malachite
Green (MG):
Crystal
Violet (CV):
Compatible for All Cationic Dyes