i
MINISTRY OF EDUCATION AND
MINISTRY OF NATIONAL
TRAINING
DEFENCE
ACADEMY OF MILITARY SCIENCE AND TECHNOLOGY
Nguyen Thanh Binh
STUDY ON ACTIVATED PERSULFATE BY
ZERO VALENT IRON AND UV TO PRODUCE
DUAL OXIDATION SYSTEM TO DEGRADE
SOME AZO DYES IN WATER
CHEMICAL DOCTORAL THESIS
HA NOI - 2019
ii
MINISTRY OF EDUCATION AND
MINISTRY OF NATIONAL
TRAINING
DEFENCE
ACADEMY OF MILITARY SCIENCE AND TECHNOLOGY
Nguyen Thanh Binh
STUDY ON ACTIVATED PERSULFATE BY
ZERO VALENT IRON AND UV TO PRODUCE
DUAL OXIDATION SYSTEM TO DEGRADE
SOME AZO DYES IN WATER
Major: Theoretical and Physical Chemistry
Code: 9 44 01 19
CHEMICAL DOCTORAL THESIS
ACADEMIC SUPERVISORS:
1. Assoc. Prof. Dr. TRAN Van Chung
2. Prof. Dr. Sc. DO Ngoc Khue
HA NOI - 2019
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ACKNOWLEDGMENTS
I assure that this is my own research. The research results shown in the
thesis are honest. Scientific conclusions of the thesis have never been published in
any other work. The scientific data were fully cited.
15th December 2019
Author
Nguyen Thanh Binh
ii
SPECIAL THANKS TO
I would like to express my deep gratitude to Assoc. Prof. Dr. Tran Van
Chung and Prof. Sc. Dr. Do Ngoc Khue for guiding deeply in helping me
throughout the process of implementing and completing the thesis.
I would like to express my sincere thanks to the Heads and Staffs of the New
Technology Institute/Academy of Military Science and Technology for supporting
and creating favorable conditions for me in the process of implementing the thesis.
I would like to thank the Heads of the Academy of Military Science and
Technology, the Training Department/Academy of Military Science and Technology
for helping me throughout the study, research and completion of the thesis.
I would like to express my thanks to Heads of College of Chemical Defense
Officer/Chemical Corps; Military Institute of Chemical-Environment/Chemical
Corps; Institute of Chemistry - Materials/Academy of Military Science and
Technology; Institute of Chemistry/Vietnam Academy of Science and Technology;
Department of Chemistry/VNU University of Science/Vietnam National University,
Hanoi; Department of Chemistry/Hanoi National University of Education helped,
during the thesis implementation.
Sincere thanks to my family, relatives, colleagues and friends for caring,
supporting, encouraging me to complete this project.
iii
TABLE OF CONTENTS
Page
1.1.
1.2.
ACKNOWLEDGMENTS
i
TABLE OF CONTENTS
iii
LIST OF SIGNS AND ABBREVIATION
vi
LIST OF TABLES
x
LIST OF GRAPHS
xii
INTRODUCTION
1
Chapter 1 OVERVIEW
The basic concept of the oxidation processes based on free radicals
5
1.1.1. The concept and classification of advanced oxidation processes
5
1.1.2. The advanced oxidation processes based on free hydroxyl radicals
7
1.1.3. The advanced oxidation processes based on free sulfate radicals
11
Status of treatment technology for textile dye wastewater
22
1.2.1. Concept, classification of dyes
22
1.2.2. Azo dyes
22
1.2.3. Dye-contaminated wastewater
27
1.2.4. Current situation of domestic and foreign researches on
28
5
treatment technology of textile dye wastewater
1.3.
Conclusion of chapter 1
31
Chapter 2 RESEARCH SUBJECT AND METHODOLOGY
33
2.1.
Research subject
33
2.2.
Instruments and chemicals
33
2.2.1. Instruments
33
2.2.2. Chemicals
34
Methods of analysis
34
2.3.1. High performance liquid chromatography method
34
2.3.2. Inductively coupled plasma - mass spectrometry method
37
2.3.3. The volumetric titration method determining the concentration
37
2.3.
of S2O82
iv
2.4.
Experimental methods
39
2.4.1. Survey, evaluating the decomposition efficiency of AZOs in
39
systems: ZVI/AZOs, PS/AZOs, ZVI/PS/AZOs and ZVI/AZOs/UV,
PS/AZOs/UV, ZVI/PS/AZOs/UV
2.4.2. Survey of factors affecting on the degradation efficiency of
40
AZOs in systems: ZVI/PS/AZOs and ZVI/PS/AZOs/UV
2.4.3. Qualitative survey of free radicals OH and SO4 in
42
ZVI/PS/AZOs and ZVI/PS/AZOs/UV systems
2.4.4. Quantitative survey of free radicals OH and SO4 in
44
ZVI/PS/AZOs and ZVI/PS/AZOs/UV systems
2.4.5. The theoretical equations applied in reaction kinetic research
44
2.4.6. The basis of quantum computing methods
48
2.4.7. Treatment of dye wastewater of La Phu, Duong Noi and Van
51
Phuc villages
3.1.
Chapter 3: RESULT AND DISCUSSION
52
Survey, evaluating the efficiency of the PS activation methods under
52
different conditions
3.1.1. The activated PS systems without UV
52
3.1.2. The activated PS systems with UV
56
3.1.3. Factors affect the AZOs decomposition in systems of
60
activated PS by ZVI under without and with UV conditions
3.2
Investigation of the kinetic characteristics of the AZOs
79
decomposition process in the activated persulfate system
3.2.1. The kinetic characteristics of the AZOs decomposition in
80
systems without UV
3.2.2. The kinetic characteristics of the AZOs decomposition in
82
system with UV
3.2.3. Results of calculating thermodynamic parameters according
to Arrhenius and Eyring equations for systems: ZVI/PS/AZOs and
86
v
ZVI/PS/AZOs/UV
3.3.
Research to determine free radicals OH and SO4 in the activated
97
persulfate systems by ZVI without UV and with UV
3.3.1. Qualitative study of free radicals OH and SO4 in the
97
ZVI/PS/AZOs system.
3.3.2. Studying on quantification of free radicals OH, SO4 in the
99
activated persulfate systems by ZVI without and with UV
3.4.
Calculating some quantumn structural parameters and proposing
110
MO, AY and BT decomposition mechanism in the activated
persulfate system
3.4.1. Some structural parameters and ability of decomposing AZOs
110
3.4.2. The estimated mechanism of the AZOs decomposing in the
113
activated persulfate systems
3.5.
Application of the activated persulfate system with UV to treat azo-
118
contaminated wastewater from some textile dyeing villages
CONCLUSION
122
LIST OF PUBLISHED SCIENTIFIC WORKS
125
LIST OF REFERENCES
126
Appendix
vi
LIST OF SIGNS AND ABBREVIATIONS
Signs
Meaning
λ
Wavelength (nm)
I
Light intensity (Lux)
∆H
Activated Enthalpy (kJ/mol)
∆S
Activated Entropy (J/mol.K)
Molecular orbital function
kB
Boltzmann constant (1.381.10-23J.K-1)
K#
The reaction equilibrium constant forming an activated complex
ε
Adsorption constant (M-1cm-1)
R
Gas constant (R=1.987 Cal/mol.K or R=8.314 J/mol.K)
h
Plank constant (h= 6.625.10-34J.s)
k
Reaction rate constant
C i
Linear combination factor
H(%)
Efficiency
Ea
Activation energy (J/mole)
E
Total energy of the molecule
∆G
Free Gibbs energy (kJ/mol)
∆G
Free activation Gibbs energy (kJ/mol)
T
Kelvin temperature (K)
C
Mole concentration (mole/L)
i
The orbital function i
v
Light frequency (Hz)
E
Redox standard potential (V)
V
Volume (L)
A
Pre-exponential constant
Tˆe
The kinetic energy operator of electron
Ĥ
The Hamilton operator
vii
Uˆ e e
Uˆ n e
r
The potential energy operator of interaction
between nucleus and electron
The potential energy operator of interaction
between electron and electron
Reaction rate
Abbreviation Phrases are abbreviated
2,4- D
2,4-Dichlorophenoxy acetic acid
2,4,5-T
2,4,5-Trichlorophenoxy acetic acid
AC
Activated Carbon
AC-MW
Activated Carbon – Micro wave
ANPOs
Advanced Non-Photochemical Oxidation Processes
AO7
Orange 7 acid
AOPs
Advanced Oxidation Processes
APOPs
Advanced Photochemical Oxidation Processes - APOPs
AY
Alizarine Yellow R
AZOs
The general form, which represents one of the azo: MO, AY and BT
BOD
Biochemical Oxygen Demand
BT
Mordant Black-T
BTEX
Benzene, Toluene, Methylbenzene, Xylene
C.I
Color Index
COD
Chemical Oxygen Demand
DCE
1,2-dichloroethene
DNT
2,4-dinitro toluene
EDTA
Ethylene diamine tetra acetic acid
ETA
Ethanol alcohol
ETAD
The Ecological and Toxicological Association of Dyes and
Organic Pigments Manufacturers
HPLC
High Performance Liquid Chromatography
ICP-MS
Inductively Coupled Plasma- Mas Spectrometry
ISCO
In Situ Chemical Oxidation
viii
IUPAC
International Union of Pure and Applied Chemistry
LD50
Lethal dose 50%
MO
Methyl Orange
MTBE
Methyl tert-butyl ete
MW
Micro wave
NTA
Citric nitrile triacetate acid
PAHs
Polycyclic aromatic hydrocarbons
PCA
p-chloaniline
PCB28
2,4,4’- Trichloro biphenyl
PCE
Perchloro ethene
PS
Persulfate
PVA
Polyvinyl alcohol
SMT
Sunfamethazine
TBA
Tert-butyl alcohol
TCA
1,1,1-trichloro ethane
TCE
Trichloroethylene
TNT
Trinitrotoluene
TOC
Total organic carbon
TRGS 905
Technischen Regeln für Gefahrstoffe 905
UV
Ultraviolet
UV-Vis
Ultraviolet - visible
VOCs
Volatile organic compounds
ZVI
Zero valent iron
ix
LIST OF TABLES
Pages
Table 1.1.
The standard reduction potential EOx/Re of some oxidation agents
5
Table 1.2.
Some advanced oxidation processes without UV radiation
6
Table 1.3.
Some advanced oxidation processes with UV radiation
6
Table 1.4.
The reactions may occur during the Fenton process
9
Table 1.5.
Some physical properties of persulfate salts
12
Table 1.6.
Physical properties of MO
25
Table 1.7.
Physical properties of AY
26
Table 1.8.
Physical properties of BT
27
Table 2.1.
The retention time (tR) corresponding to the peak HPLC of MO,
35
AY and BT
Table 2.2.
The reaction rate constants between ETA, TBA with OH, SO4
42
Table 2.3.
The qualitative experiements of OH, SO4 in ZVI/PS/AZOs system
43
Table 3.1.
Results of effecting of [ZVI] on the decomposition efficiency of
61
AZOs in systems ZVI/PS/AZOs (HAZOs %) and
ZVI/PS/AZOs/UV (HAZOs.UV %)
Table 3.2.
Results of effecting of [PS] on the decomposition efficiency of
64
AZOs in systems ZVI/PS/AZOs (HAZOs %) and
ZVI/PS/AZOs/UV (HAZOs.UV %)
Table 3.3.
Results of effecting of [AZOs] on the decomposition efficiency
68
of AZOs in systems ZVI/PS/AZOs (HAZOs %) and
ZVI/PS/AZOs/UV (HAZOs,UV %)
Table 3.4.
Results of effecting of pH on the decomposition efficiency of
72
AZOs in systems ZVI/PS/AZOs (HAZOs %) and
ZVI/PS/AZOs/UV (HAZOs,UV %)
Table 3.5.
Results of effecting of temperature on the decomposition
efficiency of AZOs in systems ZVI/PS/AZOs (HAZOs %) and
ZVI/PS/AZOs/UV (HAZOs,UV %) (HAZOs,UV %).
76
x
Table 3.6.
The temperature effecting on the AZOs reaction kinetics of in
85
the ZVI/PS/AZOs system and the ZVI/PS/AZOs/UV systems
Table 3.7.
Activation energy Ea and pre-exponential constant (A) according
88
to Arrhenius equation for systems: ZVI/PS/AZOs and
ZVI/PS/AZOs/UV
Table 3.8.
Results of calculating H#, S# and G# according to Eyring
93
equation in the systems: ZVI/PS/AZOs and ZVI/PS/AZOs/UV
Table 3.9.
Reactions occuring in systems:
100
ZVI/PS/AZOs and ZVI/PS/AZOs/UV
Table 3.10. The calculation results of [SO4], [HO] and k17, k18 in the
107
ZVI/PS/AZOs system and the ZVI/PS/AZOs/UV system
Table 3.11. The kinetic equations of reactions between AZOs and HO, SO4
109
in the ZVI/PS/AZOs system and the ZVI/PS/AZOs/UV system
Table 3.12. The quantum parameters of MO, AY and BT molecular
111
Table 3.13. The needed amount of PS and ZVI to wastewater
118
solutions of the textile dyeing villages
Table 3.14. Results of pre-treatment and post-treatment analysis of textile dye
wastewater in villages of Duong Noi, La Phu and Van Phuc
119
xi
LIST OF GRAPHS
Pages
Figure 2.1.
Diagram of a reaction device for UV
33
heated activated persulfate process
Figure 2.2.
The calibration curve for determining MO concentration by HPLC
36
Figure 2.3.
The calibration curve for determining AY concentration by HPLC
36
Figure 2.4.
The calibration curve for determining BT concentration by HPLC
36
Figure 2.5.
The reaction process according to the theory of active
46
Figure 2.6.
Graph of dependence ln (k /T) on 1/T
47
Figure 3.1.
The decomposition efficiency of MO, AY and BT
52
in systems: 1. ZVI/MO, 2. ZVI/AY and 3. ZVI/BT
Figure 3.2.
The decomposition efficiency of MO, AY and BT
53
in systems: 1. PS/MO, 2. PS/AY and 3. PS/BT
Figure 3.3.
The decomposition efficiency of MO, AY and BT
54
in systems: 1. ZVI/PS/MO, 2. ZVI/PS/AY and 3. ZVI/PS/BT
Figure 3.4.
The decomposition efficiency of MO, AY and BT in systems:
56
1. ZVI/MO/UV, 2. ZVI/AY/UV and 3. ZVI/BT/UV
Figure 3.5.
The decomposition efficiency of MO, AY and BT in systems:
57
1. PS/MO/UV, 2. PS/AY/UV and 3. PS/BT/UV
Figure 3.6.
The composition efficiency of MO, AY and BT in systems:
58
1. ZVI/PS/MO/UV, 2. ZVI/PS/AY/UV and 3. ZVI/PS/BT/UV
Figure 3.7.
Comparing the decomposition efficiency of MO in systems:
59
1.ZVI/MO, 2.PS/MO, 3.ZVI/PS/MO and 4.ZVI/PS/MO/UV
Figure 3.8.
Comparing the decomposition efficiency of AY in systems:
59
1.ZVI/AY, 2.PS/AY, 3.ZVI/PS/AY and 4.ZVI/PS/AY/UV
Figure 3.9.
Comparing the decomposition efficiency of BT in systems
59
1.ZVI/BT, 2.PS/BT, 3.ZVI/PS/BT and 4.ZVI/PS/BT/UV
Figure 3.10.
Effect of [ZVI] on the MO decomposition efficiency
in systems: ZVI/PS/MO, ZVI/PS/MO/UV at 30 minutes
62
xii
Figure 3.11.
Effect of [ZVI] on the AY decomposition efficiency
62
in systems: ZVI/PS/AY, ZVI/PS/AY/UV for 30 minutes
Figure 3.12.
Effect of [ZVI] on the BT decomposition efficiency
62
in systems: ZVI/PS/BT, ZVI/PS/BT/UV for 30 minutes
Figure 3.13.
Effect of [PS] on the MO decomposition efficiency
65
in systems: ZVI/PS/MO, ZVI/PS/MO/UV for 30 minutes
Figure 3.14.
Effect of [PS] on the AY decomposition efficiency
66
in systems: ZVI/PS/AY, ZVI/PS/AY/UV for 30 minutes
Figure 3.15.
Effect of [PS] on the BT decomposition efficiency
66
in systems: ZVI/PS/BT, ZVI/PS/BT/UV for 30 minutes
Figure 3.16.
Effect of [MO] on the MO decomposition efficiency
69
in systems: ZVI/PS/MO, ZVI/PS/MO/UV for 30 minutes
Figure 3.17.
Effect of [AY] on the AY decomposition efficiency
70
in systems: ZVI/PS/AY, ZVI/PS/AY/UV for 30 minutes
Figure 3.18.
Effect of [BT] on the BT decomposition efficiency
70
in systems: ZVI/PS/BT, ZVI/PS/BT/UV for 30 minutes
Figure 3.19.
Effect of pH on the MO decomposition efficiency
73
in systems: ZVI/PS/MO, ZVI/PS/MO/UV for 30 minutes
Figure 3.20.
Effect of pH on the AY decomposition efficiency
73
in systems: ZVI/PS/AY, ZVI/PS/AY/UV for 30 minutes
Figure 3.21.
Effect of pH on the BT decomposition efficiency
73
in systems: ZVI/PS/BT, ZVI/PS/BT/UV for 30 minute
Figure 3.22.
Effect of temperature on the MO decomposition efficiency
77
in systems: ZVI/PS/MO, ZVI/PS/MO/UV for 20 minutes
Figure 3.23.
Effect of temperature on the AY decomposition efficiency
77
in systems: ZVI/PS/AY, ZVI/PS/AY/UV for 20 minutes
Figure 3.24.
Effect of temperature on the BT decomposition efficiency
77
in systems: ZVI/PS/BT, ZVI/PS/BT/UV for 20 minutes
Figure 3.25.
The effects of temperature on the MO graph of lnC/C0-t
in the ZVI/PS/MO system
81
xiii
Figure 3.26.
The effects of temperature on the AY graph of lnC/C0-t
81
in the ZVI/PS/AY system
Figure 3.27.
The effects of temperature on the BT graph of lnC/C0-t
82
in the ZVI/PS/BT system
Figure 3.28.
The effects of temperature on the MO graph of lnC/C0-t
83
in the ZVI/PS/MO/UV system
Figure 3.29.
The effects of temperature on the AY graph of lnC/C0-t
83
in the ZVI/PS/AY/UV system
Figure 3.30.
The effects of temperature on the BT graph of lnC/C0-t
84
in the ZVI/PS/BT/UV system
Figure 3.31.
Grap of lnk=f(1/T) according to Arrhenius equation in
87
systems: (a) ZVI/PS/MO; (b) ZVI/PS/MO/UV; (c)
ZVI/PS/AY; (d) ZVI/PS/AY/UV; (e) ZVI/PS/BT; (f)
ZVI/PS/BT/UV
Figure 3.32.
Graphs of ln(k/T)=f(1/T) according to Eyring equation in
92
systems: (a) ZVI/PS/MO; (b) ZVI/PS/MO/UV; (c)
ZVI/PS/AY; (d) ZVI/PS/AY/UV; (e) ZVI/PS/BT; (f)
ZVI/PS/BT/UV
Figure 3.33.
Graph C= f(t) of the MO decomposition in systems:
97
1.ZVI/PS/MO; 2.ZVI/PS/MO+ETA; 3.ZVI/PS/MO+TBA; 4. MO
Figure 3.34.
Graph C= f(t) of the AY decomposition in systems:
97
1.ZVI/PS/AY; 2.ZVI/PS/AY+ETA; 3.ZVI/PS/AY+TBA; 4.AY
Figure 3.35.
Graph C= f(t) of the BT decomposition in systems:
98
1.ZVI/PS/BT; 2.ZVI/PS/BT+ETA; 3.ZVI/PS/BT+TBA; 4.BT
Figure 3.36.
The charge density of atoms on the MO molecule
110
Figure 3.37.
The charge density of atoms on the AY molecule
111
Figure 3.38.
The charge density of atoms on the BT molecule
111
Figure 3.39.
Comparing the decomposition kinetics of MO, AY and BT
112
in the activated PS system by ZVI without UV
Figure 3.40.
Comparing the decomposition kinetics of MO, AY and BT
110
xiv
in the activated PS system by ZVI with UV
Figure 3.41.
Diagram of the eexpected MO decomposition mechanism
115
Figure 3.42.
Diagram of the eexpected AY decomposition mechanism
116
Figure 3.43.
Diagram of the eexpected BT decomposition mechanism
117
Figure 3.44.
Decreasing of COD over time of Duong Noi,
119
La Phu and Van Phuc wastewater treatment
Figure 3.45.
Photos of Duong Noi wastewater before and after treatment
120
Figure 3.46.
Photos of La Phu wastewater before and after treatment
120
Figure 3.47.
Photos of Van Phuc wastewater before and after treatment
120
1
INTRODUCTION
In recent years, advanced oxidation processes (AOPs) have been studied and
applied to treat wastewater and contaminated groundwater in the world and
Vietnam. The AOPs is based on the in-situ free radicals which are generated in
reaction. These free radicals have high oxidation activity like hydroxyl radicals OH
(E= 2.8 V) and sulfate radicals SO4 (E= 2.6V). The free radicals selectively
react to all organic compounds in the water, decomposing and converting the
organic compounds into non-toxic or less toxic substances to humans and the
environment. The Advanced oxidation processes are known as: Fenton, Fenton photo, perozone, catazone, Fenton- electrochemical…The OH radicals are usually
produced by activating hydrogen peroxide or ozone with various activating agents
such as: transition metal ions, temperature, UV radiation,…[2], [11], [13], [17].
The method of treating organic polluted water by AOPs involves advantages
compared to traditional methods such as: fast treating time, mineralizing recalcitrant
toxic organic substances,...In some cases, AOPs are used as pretreatment methods
for biological methods. adsorption methods [1], [13], [17], [76], [89].
Recent scientific announcements by scientists on the researching and
application of other oxidants, such as persulfate and peroxymonopersulfate, are also
suitable for wastewater treatment of persistent organic pollutant. If these oxidants
are activated, they also produce free radicals which are higher oxidation activity
than the original ones. Persulfate, peroxymonopersulfate are not stronger than
hydrogen peroxide and ozone, but they are more durable than hydrogen peroxide
and ozone in solution, better soluble in water than ozone [43], [62], [85]. Specially,
the process of activating the persulfate produces free radicals SO4 (E = 2.6V) and
free radicals OH (E= 2.8V). Persulfate exists more longly in aqueous solutions,
which affects positively the decomposition of organic compounds in aqueous
environments [27], [57], [80].
Dyes are important and a long history of development in everyday life. At
first, dyes were prepared from plants and insects in nature. The dyeing industry is
development now. Dyes were mainly prepared by synthetic pathways. Azo dyes
2
occupy more than 50% of the dye global trade. Some azo dyes have been found to
cause cancer, mutations in genes and are banned worldwide. However, they are still
produced and used on a large scale in the dyeing industry now. Because they are
low production cost, easy to synthesize and some good color properties. The bonds
in the azo molecules are quite stable, showing the ability to decompose and
accumulate in the environment[18], [22], [59].
The textile industry consumes a large amount of clean water and also
discharges a similar amount of wastewater which is complex composition and
properties. This wastewater contains residual dyes from dyeing process (occupying
about 10 to 15 % of the dye initial amount) and has color, temperature, content of
COD, BOD and surfactants being very high [2], [41], [59], [85].
Vietnam had a strong textile industry in recent decades, which brings many
jobs and income to workers. Besides, it also releases a large amount of wastewater
polluting environment [2], [41], [59], [85].
The problem of textile dye wastewater is always concerned by domestic
and foreign scientists. Although there have been many traditional methods of
treating textile dye wastewater, the AOPs especially based on. In recent years,
advanced oxidation methods, especially persulfate-based AOPs have been
studied, applied and have shown superiority in the process of decomposing
organic matter in water environment. The AOPs based on persulfate having
potential to treat textile dye wastewater [1], [7], [13], [22], [41], [59]. Therefore,
this thesis topic was chosen: "Study on activated persulfate by zero valent iron
and UV to produce dual oxidation system to degrade some azo dyes in water".
* Objectives of the thesis:
Study of dual oxidation formation in persulfate-containing solution in
combination with zero valent iron powder (ZVI) and UV; Application of dual
oxidation system to decompose some azo
compounds: Methyl orange (MO),
alizarine yellow R (AY), modant black-T (BT) and treatment of textile dye village
wastewater contaminated with azo dye.
3
* Main contents of the thesis:
- Researching on activated persulfate by ZVI power combined with UV
through evaluating the decomposition efficiency of MO, AY and BT. Choose the
systems have the best decomposition of azo dyes. Studying and evaluating factors
affecting the efficiency of MO, AY and BT dye decomposition in activated
persulfate system by ZVI without UV (ZVI/PS/AZOs) and with UV
(ZVI/PS/AZOs/UV).
- Researching reaction kinetics, calculating the thermodynamic quantities of
the decomposition processes of MO, AY and BT in the activated persulfate systems
by ZVI combined with UV and with out UV. Studying to determine and quantify
OH, SO free radicals in the activated persulfate systems.
- Calculating molecular structure parameters and proposing mechanism of MO.
AY and BT decomposition in the activated persulfate systems.
- Study on the application of activated persulfate system by ZVI combined
with UV to treat azo-contaminated wastewater in some textile dye villages: Duong
Noi, La Phu and Van Phuc.
* Study methods:
Researching theory, consulting documents, overview issues related to subjects
and researching content.
The analytical methods were used in this thesis: Using HPLC, ICP-MS,
volumetric titration, colorimetric and COD methods to study the characteristics of the
decomposition processes of azo dyes and wastewater containing azo dyes. Building up
mathematical models to approximate the concentration of SO4, OH. This thesis is
based on the kinetic theory of Arrhenius and Eyring equation to calculate some
thermodynamic quantities. Using HyperChem 8.0 software to calculate quantum
parameters of methyl orange, alizarin yellow R and mordant black T.
* The scientific and practical meaning of the thesis:
Research results of the thesis contribute to clarify and develop kinetics of
AOPs processes based on activated persulfate by ZVI and UV to decompose some
azo dyes in the wastewater and creating a basis for development diversify methods
4
of treating organic pollutants in the wastewater in general and azo-contaminated
wastewater in particular.
* Outline of the thesis:
Chapter 1: Overview (4 pages); Chapter 2: Research subject and methodology
(27 pages); Chapter 3: Results and discussions (69 pages); Conclusion (3 pages);
Reference (9 pages).
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