Monitoring of organochlorine pesticides in surface waters in Hanoi and detoxification of ...

198 Pages·2002·2.36 MB·English

Monitoring of organochlorine pesticides in surface
waters in Hanoi and detoxification of organochlorine
and organophosphorous pesticides in water by
applying novel methods using ultraviolet irradiation
air ionisation and solar photocatalysis

Dissertation for Acquirement of the Degree of
Dr. rer. nat

In Faculty of Biology/Chemistry
University of Bremen, Germany

by
Dang Quang HUNG
from
Hanoi, Vietnam
Bremen, April 2002
This thesis is printed with full support from the DAAD (German Aca-
demic Exchange Service). I am particularly grateful to Dr. Christa Klaus,
Mrs. Veronica Metje and Mrs. Elke Burbach, referat 422, DAAD, Bonn for
their warm support for 4 years (1998-2002).

Date of Examination: 19 April 2002

1. Chair of Advisory Committee: Prof. Dr. W. Thiemann
2. Co-Chair of Advisory Committee: Prof. Dr. D. Beyersmann
Abstract

This thesis can be divided into two major parts: Monitoring of selected organochlorine pesti-
cides in surface waters and Study on the applying of novel Advance Oxidation Processes-
AOP (Air Ionisation and Solar Photocatalytic Oxidation) for the detoxification of waters con-
taining toxic organochlorine and organophosphorous pesticides, which are some well-known
insecticides like Lindane, 4,4´-DDT, Methamidophos (Me) and Monocrotophos (Mo).
The monitoring process was undertaken with the same procedure in two years (in the Dry
Season: Nov. 1998 and in the Rainy Season: Aug. 1999) for an evaluation of the contamina-
tion of 15 organochlorine pesticides in surface waters, by sampling of 30 water samples from
different sites (Red and Duong Rivers, irrigation canals, lakes and wells) on an area of ≈ 30
by 20 km in Hanoi and its surroundings, Vietnam. Those pesticides (HCH isomers, Hepta-
chlor, Aldrin, Endrin, 4,4´-DDT and its derivatives) have been recently banned in Vietnam
(from 1992 to 1998).
This monitoring process was an initial systematic investigation of surface water quality in
Hanoi, in order to find out a general evaluation towards the contamination of banned pesti-
cides in waters. The results showed that the pollution of those pesticides was highest in the
rivers and then in the irrigation canals, followed by the lakes and wells. Out of HCH isomers
investigated, only Lindane appeared in most of sampling sites at considerable concentration.
In the rainy season, the highest concentration of Lindane was found surprisingly in a lake wa-
ter sample (West Lake) at 107 ng l-1, while that of Σ HCHs was 122 ng l-1. Besides, 4,4´-DDT
and its derivatives were detected in most samples, and their concentrations were especially
higher in the rivers and irrigation canals. The highest concentration of Σ DDTs was found in a
Red River sample at 324 ng l-1 in the rainy season and at 232 ng l-1 in the dry season. Chlorin-
ated cyclodienes, including aldrin, endrin and heptachlor were detected at most of the sam-
pling sites at remarkable concentrations, while dieldrin and heptachlorepoxide (isomer A)
were only detected in some samples.
The photooxidation of Lindane and 4,4´-DDT (C = 5 mg l-1), the two major contaminated
0
insecticides detected in surface waters in Hanoi, was investigated using two UV irradiation
sources (High Pressure- and Low Pressure mercury lamp: HP and LP). The addition of
NaNO in the degradation of 4,4´-DDT could not significantly speed up the degradation proc-
3
ess. Besides applying the well-known oxidative agent H O , the influence of the photocatalyst
2 2
TiO (P25 Degussa) in different pH media (3, 7 and 12) on the decomposition of those 2 in-
2
secticides was extensively studied. Lindane was considerably degraded faster than 4,4´-DDT
(e.g. with the HP, 0.2 % H O at pH 7, k = 0.0139 min-1, t = 49.8 min for Lindane, while
2 2 1/2
that were k = 0.00892 min-1, t = 77.7 min for 4, 4´-DDT.
1/2
The photooxidative decomposition studies focused on the mineralisation of the two highly
toxic organophosphorous insecticides, namely Methamidophos and Monocrotophos (C = 5
0
mg l-1). The photodegradation of Me and Mo was first undertaken using the 2 UV Lamps HP
and LP with addition of H O . 50 % Me was degraded with the HP after 22.9 min when no
2 2
H O was added, while that degradation process was relatively slower for Mo (t = 166.6
2 2 1/2
min). The degradation of them was extremely fast when using the LP with or without addition
of H O . The HP was much more effective when H O was added.
2 2 2 2
Using a new developed reactor Ionised Air Pilot System 2 (IAPS-2), Mo was mineralised
drastically faster than Me. The half-life of the photodegradation of Mo was only 1.7 min (k =
0.3963 min-1), while that of Me was 59.2 min (k = 0.0117 min-1). The mineralisation of Me
and Mo was also followed by means of Ion Chromatography. Based on the concentrations of
anions, including NO -, PO 3-, SO 2- detected during and after each oxidative process, the
3 4 4
mineralisation of those insecticides was reconfirmed. The treated water samples of all oxida-
tive processes using the HP, LP and IAPS-2 were biologically tested with Daphnia and Lumi-
nescent bacteria for a confirmation of the detoxification of water contaminated with Me and
Mo after the treatment.
The photocatalytic detoxification of Me and Mo (C = 10 mg l-1) was investigated using a Lab
0
Solar Simulated Reactor (LSSR) and a new kind of solar non-concentrating Double Skin
Sheet Reactor (DSSR) in the Institute of Solar Energy Research, Hannover (ISFH). 12 di-
verse different commercial, modified and novel photocatalysists (TiO at concentrations of
2
500 and 1000 mg l-1), which are mostly pure anatase TiO powder, except well-known cata-
2
lyst P25 Degussa (70 % anatase, 30 % rutile) were tested with those reactors in the photocata-
lytic degradation of Me and Mo at different pH values of 3, 7, 12. The photonic efficiency (ζζζζ)
of them was calculated for searching for optimal catalysts.
Using the LSSR at pH 7 and 500 mg l-1 catalyst for the detoxification of Me, the highest val-
ues of ζ reached with Cat 11 (Pt-Hombikat) at 1.1 %, while that increased surprisingly to 1.78
% with Cat 8 (Mikroanatase) at 1000 mg l-1 concentration. Both the correspondent highest
values of ζ = 1.87 and 2.43 % reached with Cat 11 for the detoxification of Mo. Using the
DSSR at pH 7 and 500 mg l-1 catalyst for the detoxification of Me, the highest values of ζ
reached with Cat 1 (P25 Degussa) at 0.81 %, while that increased also to 1.1 % with Cat 8
(1000 mg l-1 concentration). For the detoxification of Mo, both the correspondent highest val-
ues of ζ = 2.94 and 3.01 % reached with Cat 11. The lowest photonic efficiency reached
mostly with Cat 12 (Bayoxide T2). The novel Cat 5 supplied by Millennium (PC 500) was
also an effective catalyst. In acidic and alkaline media (3 and 12), the photocatalytic degrada-
tion of Me and Mo was much faster than that at pH 7, the degradation rate increased around
10 times even when some low effective catalysts at pH 7 used. The DSSR was significantly
more effective in the degradation of those 2 insecticides than the LSSR.
The intermediates formed in the photooxidation processes of Me and Mo were detected and
identified using the new analytic technique - High Performance Liquid Chromatography cou-
pled with a Mass Spectrometer (HPLC-MS). The possible molecular structure of those inter-
mediates was explained based on their mass spectra (All MS and MS/MS). An initial detailed
possible photocatalytic oxidation mechanisms of the degradation of Methamidophos and
Monocrotophos has been found by combination of a proposed general photocatalytic oxida-
tion mechanism of an organic pollutant (assuming an initial oxidative attack by a hydroxyl
radical to a methyl group) with the molecular structures of identified intermediates.
Acknowledgments

I would like to express my gratitude first to Prof. Dr. W. Thiemann, my thesis supervisor for
his guidance, friendship, and support throughout the research and writing of this dissertation.
His patience and attention to details have helped me to remain on the path during the long and
arduous course of my studies. Without him, there would be no dissertation.
I would also like to thank my co-advisor Prof. Dr. D. Beyersmann for his critical reading and
useful suggestions to my dissertation.
I am particularly grateful to Prof. Dr. D. Bahnemann, Institut für Solarenergieforschung
GmbH Hameln/Emmerthal (ISFH), Außenstelle Hannover for allowing me to use different
solar reactors as well as new commercial and modified photocatalysts. I would like to thank
Dr. G. Sawage and Dipl.-Chem. D. Hufschmidt in his institute for their technical support.
My appreciation extends to the members of my dissertation committee, Prof. Dr. W. Schröer
and Prof. Dr. D. Bahnemann. Their contribution was instrumental in shaping the dissertation
the way it is represented here.
I would like to thank Prof. Dr. M. Vicker for his reading a part of my thesis.
I wish also to thank Dipl.-Chem. V. Suling, Dipl.-Chem. K. Chrobok for their participation in
the qualifying exam committee. With the members of the dissertation committee, their com-
ments and discussions have enriched and broadened the scope of the research.
I wish to acknowledge Mrs. U. Jarzak for her friendship and help in the various stages of the
work. I would like to thank Mrs. M. Gabriel for her works in biological tests. My thank ex-
tends to Dr. F. Müller and Dr. J. Wohlers for their help and discussions at the beginning stage
of my work. I would also like to thank colleagues of Centre of Environmental Chemistry, Ha-
noi University of Science.
This work has been funded by a PhD grant from the German Academic Exchange Service
(DAAD). Without this grant, this work would have been very difficult if not impossible.
I will be ever grateful for the love of my parents, my brother, and especially my wife. Without
you all being there, this dissertation would never have been completed.

Bremen, March 2002

Table of Contents I
Table of Contents

List of Figures.........................................................................................................................VI
List of Tables...........................................................................................................................XI
List of Symbols and Abbreviations....................................................................................XIII

1 Introduction..............................................................................................................1
2 Theoretical Part........................................................................................................5
2.1 Introduction of Organochlorine and Organophosphorous Pesticides............................5
2.1.1 Chemical, Physical and Toxicological Properties................................................8
2.1.1.1 Lindane and HCH isomers.......................................................................8
2.1.1.2 Heptachlor and Heptachlorepoxide (isomer A)........................................8
2.1.1.3 Aldrin, Dieldrin and Endrin......................................................................9
2.1.1.4 4,4´-DDT and its derivatives..................................................................10
2.1.1.5 Methamidophos......................................................................................12
2.1.1.6 Monocrotophos.......................................................................................13
2.1.2 Transport, Distribution and Degradation of Pesticides in the Environment.......14
2.2 Use of Pesticides in Vietnam.......................................................................................15
2.3 Basis of Analytical Method..........................................................................................17
2.3.1 Solid Phase Extraction........................................................................................17
2.3.2 Gas Chromatography (GC).................................................................................18
2.3.2.1 Electron Capture Detector (ECD)..........................................................18
2.3.2.2 Nitrogen-Phosphorous Detector (NPD).................................................19
2.3.2.3 Mass Spectrometry (MS) and GC-MS...................................................19
2.3.3 High Performance Liquid Chromatography (HPLC).........................................21
2.3.3.1 Ultraviolet (UV) Detector......................................................................22
2.3.3.2 LC-MS....................................................................................................22
2.3.4 Ion Chromatography...........................................................................................23
2.4 Biological Test.............................................................................................................23
II Table of Contents
2.4.1 Daphnia Test.......................................................................................................23
2.4.2 Luminescent Bacteria Test.................................................................................24
2.5 Applied Oxidative Processes for the Treatment of Pesticides in Wastewater.............25
2.5.1 Direct Photolysis by UV.....................................................................................25
2.5.2 UV/H O Process................................................................................................25
2 2
2.5.3 Air Ionisation Process.........................................................................................26
2.5.4 Sunlight (UV) / TiO Process.............................................................................27
2
2.6 Conventional and Novel Reactors................................................................................28
2.6.1 High Pressure (HP) and Low Pressure (LP) Mercury Lamps............................28
2.6.2 Ionised Air water treatment Pilot System (IAPS)..............................................29
2.6.3 Lab Simulated Solar Reactor (LSSR).................................................................30
2.6.4 Double-Skin Sheet Reactor (DSSR)...................................................................31
2.7 Mechanism of the Pollutant degradation by UV/H O ................................................32
2 2
2.7.1 Properties of UV Radiation................................................................................32
2.7.2 Properties of H O ..............................................................................................33
2 2
2.7.3 General Principle of Photochemistry..................................................................35
2.7.4 Mechanism of H O Photolysis in Water...........................................................37
2 2
2.7.4.1 Hydroxyl radical generation...................................................................37
2.7.4.2 H O Photolysis......................................................................................38
2 2
2.7.4.3 Hydrogen abstraction.............................................................................38
2.7.4.4 Radical-radical reactions........................................................................39
2.7.4.5 Electrophilic edition...............................................................................39
2.7.4.6 Electron-transfer reactions.....................................................................40
2.8 Mechanism of the Pollutant degradation by UV/TiO .................................................40
2
2.9 Photokinetic analysis....................................................................................................43
3 Experimental Methods...........................................................................................44
3.1 Experimental Chemicals and Solvents.........................................................................44
Table of Contents III
3.2 Analysis of organochlorine pesticides in surface waters in Hanoi...............................44
3.2.1 Sampling.............................................................................................................44
3.2.2 Sample Preparation.............................................................................................44
3.2.3 Analytic Condition: GC-ECD............................................................................47
3.3 Photooxidation of lindane and 4, 4´-DDT using HP, LP/H O , /TiO .........................48
2 2 2
3.4 Oxidative Processes of Methamidophos (Me) and Monocrotophos (Mo)...................48
3.4.1 Photooxidation using HP, LP/H O ....................................................................49
2 2
3.4.2 Oxidation using IAPS.........................................................................................49
3.4.3 Solar Photocatalytic Detoxification....................................................................50
3.4.3.1 Conventional and Novel Photocatalyst TiO ..........................................50
2
3.4.3.2 Photocatalytic Oxidation using LSSR....................................................52
3.4.3.3 Photocatalytic Oxidation using DSSR...................................................52
3.4.4 Sample Preparation.............................................................................................52
3.4.5 Analytic Condition: GC-NPD, GC-MS and HPLC-MS.....................................53
3.4.6 Ion Chromatography...........................................................................................53
3.4.7 Biological Tests of Treated Water Samples.......................................................54
3.4.7.1 Daphnia Test...........................................................................................54
3.4.7.2 Luminescent Bacteria Test.....................................................................54
4 Results and Discussion...........................................................................................55
4.1 Contamination of Organochlorine Pesticides in Surface Waters in Hanoi..................55
4.1.1 Lindane and HCH isomers.................................................................................55
4.1.2 Chlorinated cyclodienes.....................................................................................59
4.1.3 4,4´-DDT and its derivatives..............................................................................62
4.1.4 Conclusions........................................................................................................67
4.2 Photooxidation of Lindane and 4,4´-DDT using HP, LP/H O , /TiO ........................68
2 2 2
4.2.1 Lindane...............................................................................................................68
4.2.1.1 Effect of pH, H O Concentration and UV-light sources HP, LP..........68
2 2
4.2.1.2 Effect of pH, TiO Concentration and UV-light sources HP, LP...........73
2
IV Table of Contents
4.2.1.3 Kinetic Evaluation of Lindane Destruction by HP, LP.........................74
4.2.2 4,4´-DDT............................................................................................................75
4.2.2.1 Effect of pH, H O Concentration and UV-light sources HP, LP..........75
2 2
4.2.2.2 Extended studies of pH, NaNO , TiO and UV-light sources HP, LP...79
3 2
4.2.2.3 Kinetic Evaluation of 4,4´-DDT Destruction by HP, LP.......................83
4.2.3 Conclusions........................................................................................................86
4.3 Oxidative Processes of Me and Mo using HP, LP and IAPS-2...................................87
4.3.1 Methamidophos..................................................................................................87
4.3.1.1 Photooxidation using HP, LP/H O ........................................................87
2 2
4.3.1.2 Photooxidation using IAPS-2.................................................................88
4.3.1.3 Kinetic Evaluation of the Degradation of Methamidophos....................89
4.3.1.4 Determination of the Degree of the Mineralisation using IC.................90
4.3.1.5 Identification of methamidophos using GC- and LC-MS......................93
4.3.1.6 Daphnia Test of Oxidative Processes.....................................................93
4.3.1.7 Luminescent Bacteria Test of Oxidative Processes...............................94
4.3.2 Monocrotophos...................................................................................................96
4.3.2.1 Photooxidation using HP, LP/H O ........................................................96
2 2
4.3.2.2 Photooxidation using IAPS-2.................................................................97
4.3.2.3 Kinetic Evaluation of the degradation of Monocrotophos.....................98
4.3.2.4 Determination of the Degree of the Mineralisation using IC.................98
4.3.2.5 Daphnia Test of Oxidative Processes...................................................100
4.3.2.6 Luminescent Bacteria Test of Oxidative Processes.............................101
4.4 Oxidative Processes of Me and Mo using LSSR and DSSR......................................103
4.4.1 Solar Photocatalytic Oxidation of Me and Mo using LSSR.............................103
4.4.1.1 Degradation of Me: Effect of pH.........................................................103
4.4.1.2 Degradation of Me: Effect of TiO concentration................................106
2
4.4.1.3 Degradation of Me: Effect of TiO catalysts........................................107
2
4.4.1.4 Kinetic Results for the Degradation of Me using LSSR......................110
4.4.1.5 Degradation of Mo: Effects of pH, catalysts concentration and type..112
4.4.1.6 Kinetic Results for the Degradation of Mo using the LSSR................115
4.4.2 Solar Photocatalytic Oxidation of Me and Mo using DSSR............................117
4.4.2.1 Degradation of Me: Effects of pH, catalysts concentration and type...117
4.4.2.2 Kinetic Results for the Degradation of Me using DSSR......................120
4.4.2.3 Degradation of Mo: Effects of pH, catalysts concentration and type..122
4.4.2.4 Kinetic Results for the Degradation of Mo using the DSSR................125