Study of Organic Photocatalytic Degradation Mechanism

in Textile WWTP Effluent Treatment by Using

Immobilized TiO2

Nanofibers Composite Catalyst

Overseas Research Grant

Marisa Handajani

Water and Wastewater Engineering Research Group Faculty of Civil and Environmental Engineering

INSTITUT TEKNOLOGI BANDUNG

Overseas Research Grant

The Asahi Glass Foundation 2012

Outlines

1. Background, Objectives

2. Methods

3. Results and Discussion3. Results and Discussion

4. Conclusion

5. Outputs

Team Members

Researchers:

1. Dr-Ing. Marisa Handajani, ST., MT.

2. Prof. Suprihanto Notodarmajo, Ph.D

Students:

1. Doni Sugiyana, ST., M.Eng. (Doctoral program)

2. Wulan Saprihatini (Master Program)

(Indonesia : 2699; West Java : 1500}*

33% Garment1% Fiber

Direct discharge

Treated

Textile Industy in West Java

Organic, color,salt ions, metals

Excessive: Organic,color& salt ions

Background

58% Weaving &

Dyeing Finishing

Dyeing wastewater:

100 – 1000

m3/day/company

*Indonesian Textile Assc. 2010

8% Spinning

Recycle, reuse

WWTP

POSTPOST--

TREATMENTTREATMENT

POSTPOST--

TREATMENTTREATMENT

& salt ions

Photocatalytic Treatment UV/TiO

2

• Effective degradation of organic & color

Potential for Treatment

of Textile WWTP Effluent:

TiO2

+ UV(λ 254 nm) → TiO2

(e−CB

+h+VB

)

TiO2(h+

VB) + H

2O → TiO

2+H+ +OH•

TiO2

(h+VB

) + OH − → TiO2

+OH•

TiO (e− ) + O → TiO +O − •

• No excess sludge

• Rapid treatment process

Background

TiO2(e−

CB) + O

2 → TiO

2+O

2− •

O2

−• + H + → HO2•

Organic + OH• → degrada�on products

Organic + h+VB

→ oxida�on products

Organic + e-CB

→ reduc�on products

• Rapid treatment process

• Reusable

• Low process cost

Improvement of

immobilized particles

in this research:

Development of Immobilization Technique

for Photocatalytic Treatment of Wastewater

Catalyst separation

Composite

(fiber-based)

Background

Suspended particles Immobilized particles

Catalyst separation

problem Catalyst size

(nano-sized particle)

• Practical for application

(fiber-based)

• Lesser contact area

• Attachment strength

problemMechanism of

Organic

Degradation??..

To Investigate..

The mechanism of organic degradation during

photocatalytic process of

textile WWTP effluent treatment by using

Objectives

textile WWTP effluent treatment by using

immobilized TiO2

nanofibers composite catalyst

TiO2 Nanofiber-Nanoparticles Composite

Annealing

(550oC, 60 min)

TiO2

Nanofibers

Immobilized on Glass Plates

TiO2

Nanofibers

Immobilized on Glass Plates

After Annealing

Methods

Before Annealing

As-spun Nanofiber

(Electrospinning)Nanofiber+Nanoparticles

(Sol-gel, Dip-coating)

TiO2

Nanofibers-Nanoparticles

Immobilized on Glass Plates

TiO2

Nanofibers-Nanoparticles

Immobilized on Glass Plates

Annealing

(550oC, 60 min)

SEM images

CompositeNanofibers

Methods

Catalyst distribution: 4.26 mg-TiO2/cm2

5000x 5000x

10000x 10000x

UV lamp

Inlet Outlet

Stirrer

Pump

Wastewater chamber

Methods

UV Lamps:UV-C, 3 x 15 W, λ 254 nm

Photoreactor

Catalyst:Glass plates in chamber (500 mL)

Simulated Wastewater

Containing Reactive Black 5 (azo dyes)

Reactive Black 5 (RB5)

• (C26

H21

N5Na

4O

19S

6)

TARGET WASTEWATER

Methods

Real Textile WWTP

Effluent

Characteristics:

• Company : Rancaekek, Bandung• (C26

H21

N5Na

4O

19S

6)

• Molecular weight: 991.8

• Dye concentration: 10 mg/L

• Molecular structure:

(CH2)2 – O2S

O

SO3Na

N = N N = NOH NH2

NaO3S SO3Na

SO2 – (CH2)2

O

NaO3S

• Company : Rancaekek, Bandung

• Process : Cotton Dyeing Finishing

• Wastewater discharge : 345 m3/d

• WWTP Process:

• Coagullation-Flocculation

• Activated sludge

0,4

0,5

0 min

60 minDye chromophore cleavage

Organic compounds

cleavageSlower

0 min

Results & Discussion

UV-vis absorbance spectra (WWTP effluent)

5 hrs

0

0,1

0,2

0,3

250 300 350 400 450 500 550 600 650 700

Abs

orba

nce

Wavelength (nm)

60 min

120 min

180 min

240 min

300 min

cleavageFaster

Complete decolorization: 5 hrs

40

50

(mg/

L)

TOC

COD

Mineralization

Results & Discussion

Decolorization (λmax 664 nm)

0,8

1

Decolorization – Mineralization (WWTP effluent)

0

10

20

30

0 1 2 3 4 5

Con

cent

ratio

n (m

g/L)

Time (hour)

COD

0

0,2

0,4

0,6

0 60 120 180 240 300

A/A

0

Time (hour)

69%

91%

69%

100%

0 1 2 3 4 5

0,25

0,300 min

60 min

120 min

UV-vis absorbance spectra (RB5)(CH2)2 – SO2

O

SO3Na

SO2 – (CH2)2

O

SO3Na

N = N N = NOH NH2

NaO3S SO3Na

Results & Discussion

Aromatic Rings

CleavageNaphthalene, Benzene

0 min 2 hrs

0,00

0,05

0,10

0,15

0,20

200 250 300 350 400 450 500 550 600 650 700

Abs

orba

nce

Wavelength(nm)

120 min

180 min

240 min

300 min

k’: 0.039 min-1 (1st order )

Complete decolorization: 2 hrs

Cleavage of azo bonds

Naphthalene

Benzene Azo chromophore cleavage

60

70

80

(mg/

L)

TOC

COD0,8

1

Mineralization

Results & Discussion

Decolorization (λmax 592 nm)

35%

Decolorization – Mineralization (RB5)

0

10

20

30

40

50

60

0 2 4

Con

cent

ratio

n (m

g/L)

Time (hour)

0

0,2

0,4

0,6

0 60 120 180 240 300

C/C

0

Time (hour)

35%

50%

100%

0 1 2 3 4 5

3,E+06

4,E+06

5,E+06

6,E+06

7,E+06

8,E+06

9,E+06

C

Abundance

3,E+06

4,E+06

5,E+06

6,E+06

7,E+06

8,E+06

9,E+06

C

Abundance

E

2,E+06

3,E+06

4,E+06

5,E+06

6,E+06

7,E+06

8,E+06

9,E+06

B

Abundance

GC/MS Results for Degradation of RB5

UV irradiation: 1 hr UV irradiation: 3 hrs UV irradiation: 5 hrs

Results & Discussion

0,E+00

1,E+06

2,E+06

1,00 1,10 1,20 1,30 1,40 1,50 1,60 1,70 1,80

D

B

Time

->

A

0,E+00

1,E+06

2,E+06

1,00 1,10 1,20 1,30 1,40 1,50 1,60 1,70 1,80

D

Time

->

FG

0,E+00

1,E+06

2,E+06

1,00 1,10 1,20 1,30 1,40 1,50 1,60 1,70 1,80

A

B

Time

->

Compound /Ret. time

(min)

Main fragments (m/z)

A (1.41)45,59,73,89,96,105,207

B (1.26)45,55,73,87,103,116,178,191, 281

Compound /Ret. time

(min)Main fragments (m/z)

A (1.41) 45,59,73,89,96,105,207

B (1.26)45,55,73,87,103,116,178,191, 281

C (1.22) 45,57,62,73,89,94,178

D(1.14) 47,65,94,148

Compound /Ret. time

(min)Main fragments (m/z)

C (1.22) 45,57,62,73,89,94,178

D (1.14) 47,65,94,148

E (1.19)45,57,73,87,94,105,116,122

F(1.13) 45,47,65,94

G (1.11) 45,57,62,73,90

Symbol Compound Molecular structureMolecular

weightIrradiation time (hour)

1 3 35

A 2,7-diamino,3,6,8-trihidroxy naphtalene

207 √ √

B 1-sulfonat,2-(4-aminobenzenesulfonil) ethanol

281 √ √

C 3,6,8-trihidroxy naphtalene

NH2

(CH2)2 – O2S

O

SO3H

OH

HO OH

H2N NH2

OH

Identification of degradation products (RB5)

Results & Discussion

C 3,6,8-trihidroxy naphtalene178 √ √

D Phthalic anhydride 148 √ √

E Benzoic acid 122 √

F Phenol 94 √

G Oxalyc acid (COOH)2 90 √

OHHO

O

O

OCOOH

OH

Mechanism of degradation (pathway) – RB5

N = N N = NOH NH2

NaO3S SO3Na

(CH2)2 – O2S

O

SO3Na

SO2 – (CH2)2

O

NaO3S

NH2

(CH2)2 –O2S

O

SO3H

2. Cleavage of C–C, C–N and C–S bonds

1. Cleavage of azo bond

(Product B)

Results & Discussion

H2N NH2

OH NH2

HO3S SO3H

H2N NH2

OH NH2

HO3S SO3H

OH

HO OH

H2N NH2

NH2

OH

OH

OHHO

OH

OHOH

2. Cleavage of C–C, C–N and C–S bonds

(Product A) (Product C)

(Product F)

NH2

(CH2)2 –O2S

O

SO3H

(Product B)

Mechanism of degradation (pathway) – RB5

Results & Discussion

O

O

O

3. Cleavage of naphtalene rings

(Product D)

COOH

COOH

COOHOH

OHHO

(Product C) (Product E)

OH

OHOH

COOH

COOH

COOH CO2 + H2OCH3COO-

, HCOO-

, (COOH)2

4. Cleavage of benzene rings

5. Mineralization(Product F)

(Product G)

(Product E)

pH of Photocatalytic Process

1110,2

9,1 8,8 8,5 8,3

8

10

12

Results & Discussion

Degradation Pathway

Azo dyes

Intermediates(aromatic amines)

OH•, O2

- •

2

4

6

8

0 1 2 3 4 5

pH

Time (hrs)

Formation of small

molecules organic acids

(aromatic amines)

Destruction of intermediates(aliphatic acid, aromatic acid)

Mineralization

OH•, O2

- •

OH•, O2

- •

• Photocatalytic treatment by using TiO2 composite catalyst for

textile wastewater contain azo dyes was accomplished

through 2 steps:

o Cleavage of azo chromophore

o Destruction of organic intermediates

Conclusion

• Photocatalytic treatment could degrade intermediates

(aromatic amines) to be smaller molecule organic acids.

• Photocatalytic degradation treatment by using immobilized

composite catalyst was effective for mineralization of textile

WWTP effluent contain azo dyes.

Thank you for your attention