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