Photocatalytic Treatment of

Colored Wastewater
Susan M. Gallardo, Dr. Engg.
& Jurex Gallo PhD(cand.)
Chemical Engineering Department
De la Salle University

PCIEERD 4th Anniversary

EDSA Shangri-La Hotel, Ortigas Center
June 27, 2014

ERDT RESEARCH PROGRAM

TRACK: Environment & Infrastructure
Dr. Benito Pacheco chair

DRINK: Drinking water for everyone

Dr. Analiza Rollon head

Dr. Susan Gallardo- Project Leader

Dr. Josephine Borja & Dr. Carmela Centeno coproponent
Dr. Anton Purnomo, Engr. Eden Mariquit & Kathleen
Lansigan - Project assistants
Jurex Gallo (PhD scholar), Kerry Cabral & Mary Ann
Mactal (MS scholars)
Prof. Hirofumi Hinode & Dr. Pailin Ngaotrakanwiwat

Saffron Phils. Incorporated industry partner

Time line of the R & D Program

RESEARCH ACTIVITY

2008

2009
ERDT
Monitoring
Visit

2010
ERDT
Monitoring
Visit

2011

2012

Survey of Textile Industry,

Dye Persistency Test
Preparation of Catalyst by
Solgel and Catalyst
Charaterization

Effect of TiO2 Loading on

Photocatalytic Decolorization of
Methyl Orange
Optimization of Parameters in
photocatalytic degradation of
TBD and Methyl Orange
Development of a Recirculating
Reactor in Photocatalytic TBD
Degradation
Pilot Scale Investigation of Solar
Photodegradation of Textile
Wastewater with TBD

OUTPUT
Presentation in 2nd
ERDT Conference
2008
Progress Report,
Dissemination
Workshop,
Presentation in 3rd
ERDT Conference
and RSCEReport,
2009
Progress
Dissemination
Workshop,
Presentation in 5th
ERDT Conference
and RSCE 2010
Presentation in 7th ERDT
Conference and RCCE
2011, Patent Application

Publications in AEJ
and AJChE
Operation Manual,
Terminal Report and
Thesis

Plant Visit (Saffron Philippines Inc.)

April 13, 2009

[L-R] Mr. Maca, Mr. Chu, Mr.

Dacanay, Mr. Cabral, Mr. Gallo and
Dr. Gallardo

Plant Visit (Saffron Philippines Inc.)

April 13, 2009

Plant Visit (Saffron Philippines Inc.)

April 13, 2009

List of Publications
(1) Gallo, J., Borja, J., Mariano m., and Gallardo , S., Photocatalytic Degradation of Turquoise Blue Dye Using Immobilized
AC/TiO2: Optimization of Process Parameters and Pilot Scale Investigation. Accepted for Presentation in RSCE 2014.
(2) Gallo, J., Borja, J., Salim, C., Ngaotrakanwiwat, P., Hinode, H., and Gallardo S. 2012. Optimization for Photocatalytic Color
Removal of Turquoise Blue Dye C.I. 199 in Immobilized AC/TiO2 and UV System using Response Surface Methodology Asean
Engineering Journal,
(3) Mariano, M., Kho, M and Lucanas A. Pilot Scale Investigation of the Solar Photodegradation of Wastewater Containing TBD
using Nanotitania- Activated Carbon Composite Catalyst, 2012. BS Thesis De La Salle University. Manila
(4) Mactal M., Optimization of Process Parameters for the Photocatalytic Removal of TBD in Water Matrix using AC/Nanotitania
Catalyst. 2011. MS Thesis De La Salle University. Manila
(5) Gallo, J., Borja, J., Salim, C., Ngaotrakanwiwat, P. and Hinode, H., 2011. Nanotitania- Activated Carbon with Enhanced
Photocatalytic Activity: A Comparison Between Suspended and Immobilised Catalyst for Turquoise Blue Removal, Asean
Journal in Chemical Engineering, Vol. 11, No. 2, pp. 59-69.
(6) Gallo, J., Borja, J., Gallardo, S., Salim, C., Ngaotrakanwiwat, P., & Hinode, H. Development of a Photocatalytic Reactor with
Immobilized AC for Turquoise Blue Removal. Poster Presentation in the 7th ERDT Conference 2011.
(7) Gallo, J., Borja, J., Gallardo, S., Ngaotrakanwiwat, P., & Hinode, H. (2011). Photocatalytic degradation of turquoise blue dye in
immobilized nanoTiO2-AC and UV system: Optimization using response surface methodology. In the proceedings of 3 rd RCCE.
(8) Gallo, J., Mactal, M., Borja, J., Gallardo, S., & Hinode, H. (2010). Nanotiitania-activated carbon with enhanced photocatalytic
activity: A comparison between suspended and immobilized catalyst for turquoise blue removal. In the Proceedings of 17 th
RSCE.
(9) Cabral, K., Gallo, J., Salim, C., Hinode, H., Borja, J., & Gallardo, S. (2010). Optimization of process parameters using BoxBehnken experimental design for the photocatalytic decolorization of methyl orange in aqueous medium. In the Proceedings of
5th ERDT Conference: Philippine Competitiveness through ERDT. Manila, Philippines.
(10)Gallo, J., Cabral, K., Centeno, C., Borja, J., & Gallardo S. (2009). Characterization of nano-titania prepared by sol-gel method
and photocatalytic studies in dye degradation. In the Proceedings of ASEAN RSCE: Chemical Engineering at the Forefront of
Global Challenges.
(11)Cabral. K. P., Gallo, J. C., Borja, J. Q. & Gallardo, S. M. (2009). Effect of TiO 2 loading on the photocatalytic decolorization of
methyl orange. In the Proceedings of 3rd ERDT Conference: Post-graduate Multi-disciplinary Approach to Solving Philippine
Problems. Manila, Philippines.
(12)Cabral, K. P., Borja, J. Q., Centeno, C. R., & Gallardo, S. M. (2008). Synthesis, characterization, and activity testing on
nanotitania photocatalyst calcined at 400 and 500 oC: A start-up experiment. In the Proceedings of 2nd ERDT Conference:
Synergy in Multi-disciplinary R&D. Manila, Philippines.
(13)Gallo, J. C., Co, R. A. S., Mariquit, E. G., Cabral, K. P., Borja, J. Q., & Gallardo, S. M. (2008). Assessment of the colored
wastewater in the Philippine textile industry and preliminary study on the color removal of wastewater using photocatalysis. In
the Proceedings of 2nd ERDT Conference: Synergy in Multi-disciplinary R&D. Manila, Philippines.

Introduction
The release of the synthetic dyes in textile industries in the
environment, is considered to be a major environmental
issue that needs to be addressed properly
Employing Advanced Oxidation Processes (AOPs) using
UV-TiO2 provides a promising treatment of these
commercial wastewaters
The target users of these technologies would be the
company involved in the textile industries
to meet standards of DENR,
prevent water pollution and degradation of aquatic life
foster environmental responsibility within the industry ensuring
sustainable development
8

Objectives of the Study

The research objective is to treat wastewater effluent
containing dyestuffs by photocatalysis, particularly using
the UV-TiO2 system.
Specific objectives are as follows:
To assess the color problem of a textile industry in the Philippines.
To prepare a composite catalyst AC/TiO2 using the sol-gel method
for photocatalytic oxidation of dye.
To characterize the catalysts prepared using BET, SEM- EDX,
TEM, TGA , FTIR and XRD.
To perform adsorption and photocatalytic activity tests to determine
the performance of the catalysts prepared
To conduct optimization of operating parameters
To conduct kinetic study and toxicity study
To facilitate transfer of technology to an industry partner
9

Photocatalysis

Semiconductors
need
to
absorb energy from light that
is equal or more than its
energy gap

Electron and hole partake

in redox reaction producing
hydroxyl radicals and
superoxide.

Electrons are promoted from

valence band to conduction
band leaving electron hole
pair

Hydroxyl radicals and

superoxide formed are
responsible for degradation
of dyes.

10

LABORATORY INVESTIGATIONS

11

Methods: Scientific Equipment

and Laboratory Facilities

Chemicals

Hot plate Stirrer

Ultrasonicator

Prepared Catalyst
Oven

Furnace

Nano-Titania Catalyst Preparation by Solgel12

Methodology:
Catalyst Preparation

13

Methods: Scientific Equipment

and Laboratory Facilities

SEM-EDX
Analyzer
Physics Dept
DLSU

TEM Equipment
Tokyo Tech
XRD Equipment
Tokyo Tech

BET Surface
Analyzer
Chem Eng DLSU

FTIR Equipment
Physics Dept DLSU

UV-VIS
Spectrophotometer

Catalyst Characterization

TG-DTA Equipment
borrowed from UPD

14

Methods: Scientific Equipment

and Laboratory Facilities
Photocatalytic
Reactors

Photocatalytic activity testing

15

Overview of Preliminary Results

Dye Persistency Test

A/A0

Photocat-Baker TiO2

Acid Dye

1.00000
0.90000
0.80000
0.70000
0.60000
0.50000
0.40000
0.30000
0.20000
0.10000
0.00000

Direct
Dye

Turquoise
blue
Source:
Astrazone
Saffron

Disperse
Dye

blue
Source: PTRI
Dianix orange
Source: PTRI

Reactive
Dye

Reactive blue
Source: PTRI

Basic Dye

Telon orange
Source: PTRI

Time (hr)
Acid

Basic

Reactive

Disperse

Direct

ORDER OF PERSISTENCY

Acid dye

Direct dye

Basic dye

Disperse dye

Reactive dye

Acid dye is the most persistent dye followed by direct dye, basic
dye, disperse dye and reactive dye
TBD which belongs to direct dye generates high colored
wastewater which is difficult to degrade

16

Turquoise Blue Dye generates high

colored wastewater in a local textile mill
Turquoise blue CI 199
Chemical formula

C32H16N8S2O6CuNa2

Molecular weight

781.8 g/mol

Solubility in water at 80degC

60g/L

TBD solution

TBD is a direct dye

17

Overview of Preliminary Results

Nanotitania synthesized using sol-gel method

%
Decolorization
in 120 min

Characteristics

TiO2 Photocatalyst Samples

J. T. Baker TiO2

nTiO2 Calcined
at 400 oC

nTiO2 Calcined
at 500 oC

Surface Area (m2)

Crystallite Size (nm)

2.59
44.3 - >100.0

126.17
9.6 17.0

106.14
12.5 17.9

Crystal Structure

Anatase, Rutile,
& Brookite

Anatase &
Brookite

Anatase &
Brookite

3.36
27.45
14.53
15.32
6.73

3.25
72.92
70.19
60.26
41.26

3.21
77.66
75.70
56.73
35.71

Energy Band Gap (eV)

50 ppm T.O.
60 ppm T.O.
80 ppm T.O.
100 ppm T.O.

Nanotitania (TiO2) photocatalyst tested for photoactivity towards Telon

Orange
Nanotitania calcined at 400 degC has the highest surface
area and also showed the highest photocatalytic activity

18

Results and Discussions

Catalysts Synthesized by Solgel

AC/TiO2 with high AC loading [3:10 AC/TiO2] showed a dark color while
AC/TiO2 with low AC loading [1:1600 AC/TiO2] is whitish in color

19

Results and Discussions

Summary of Characterization Results

BET Surface area increases with more AC loading.

Uniform distribution of AC and TiO2 as more AC is added
No significant change in band gap.

20

Results and Discussions

Performances of AC/TiO2 with Various AC Loading

Using 1:1600 AC/TiO2 (8.72% AC loading), a total color removal for

TBD was observed in 120 minute irradiation while it took longer
for bare TiO2 to completely degrade TBD in 150 minute irradiation.
21

Results and Discussions

Immobilized Catalyst [1:1600 AC/TiO2]

SEM Image of Etched Glass Plate

Immobilized Catalyst Installed in Glass Holder

Using 1:1600 AC/TiO2 (8.72% AC loading) was successfully

immobilized in glass plate using PEG as binder.

22

Results and Discussions

Photolysis using Recirculating Reactor

Photolysis effect 3.93% color removal of TBD

23

Results and Discussions

Dark Adsorption using Recirculating Reactor

Dark experiment showed a TBD color removal of 21.7% due to

adsorption.
24

Results and Discussions

Optimum Operating Conditions under AC/TiO2-UV system

90.01 % color removal

for TBD at optimum
conditions

25

Results and Discussions

COD Removal

99.42% COD removal was observed after 240 minute

photocatalytic treatment.
26

Results and Discussions

Photocatalytic Degradation of Textile Wastewater under AC/TiO2 UV System

86.40% color removal in 6-hour irradiation.

27

Results and Discussions

Photocatalytic Degradation of TBD under Visible Light

Visible light

38.50 % color removal for TBD under Visible Light.

28

Results and Discussions

Fit of Kinetic Data

The kinetic data fits the Langmuir Hinshelwood model with R2 = 0.9759
The kinetic parameters are kr = 0.096191 mg L-1 min-1 and K =0.128966 L mg-1
29

Results and Discussions

Recyclability Test Results

The efficiency of immobilized AC/TiO2 is not lower than 60% after

7 cycles.
30

Results and Discussions

Toxicity Test Results

Transformation from toxic to non-toxic after 6 hour irradiation.

31

Conclusions
The TiO2 synthesized by sol-gel at 400degC is nano-sized.
The addition of AC to TiO2 has no significant effect on the
band gap energy of the composite catalyst.

High photocatalytic efficiency was observed on AC/TiO2

with low AC loading [8.72 percent AC loading]
AC/TiO2 was successfully immobilized in glass plates using
PEG as binder.
TBD removal increases with catalyst loading and UV
intensity while decreasing with initial dye concentration,
initial dye solution pH and recirculating flow rate.
The initial dye concentration has the highest influence in
TBD removal.
32

Conclusions
Using optimum conditions under UV light, 90.0 % color
removal was observed for TBD while 86.4 % color
removal for textile wastewater with TBD stream. 38.5 %
color removal for TBD was observed under visible light.

Photocatalytic degradation of TBD follows the LangmuirHinshelwood equation

Textile wastewater with TBD stream was transformed from
toxic to non-toxic after 6-hour photocatalytic treatment.
The efficiency of immobilized AC/TiO2 is not lower than
60% after 7 cycles.

33

PILOT PLANT INVESTIGATION

34

Methodology:
Catalyst Immobilization

35

Methodology:

Photocatalytic
Reactor

1m

AC/
1.8 m

Photocatalytic activity testing

36

Results and Discussions: Pilot Plant

Investigation

54.80% color removal was observed at 1.5 hours residence

time with 3 recirculation passes.

37

Conclusions
In pilot plant investigation, 54.80% color removal was
observed at 1.5 hours residence time with 3 recirculation
passes.

38

Acknowledgment

DOST PCIEERD
DLSU Manila
Saffron Philippines Inc.
Tokyo Institute of Technology, Japan
Burapha University, Thailand
Martin Mariano, Michael Kho and Alton Lucanas
PTRI

Thank
you!!
39