Development and application of Fenton and UV-Fenton processes at natural pH using chelating ...

271 Pages·2016·4.42 MB·English

Development and application of Fenton and UV-Fenton
processes at natural pH using chelating agents for the
treatment of oil sands process-affected water
By
Ying Zhang

A thesis submitted in partial fulfillment of the requirements for the degree of

Doctor of Philosophy
in
Environmental Engineering

Department of Civil and Environmental Engineering

University of Alberta

○C Ying Zhang, 2016
ABSTRACT
The increasing amount of oil sands process-affected water (OSPW), its high toxicity
towards aquatic organisms due to naphthenic acids (NAs) and other organics, and the zero
discharge practice of the oil sands industry urge researchers to seek effective approaches for its
treatment. Advanced oxidation processes (AOPs) have been successfully used to degrade
recalcitrant NAs and reduce the overall toxicity of OSPW towards selected test organisms.
Fenton and photo-Fenton processes as very common AOPs have not been applied on the OSPW
treatment yet. Due to the precipitation of Fe at pH > 3, nitrilotriacetic acid (NTA) and [S,S]-
ethylenediamine-N,N’-disuccinic acid ([S,S]-EDDS) have been employed to form complex with
iron and enable Fenton reactions at high pH. The overall goal of this research was, therefore, to
investigate the reaction mechanisms and kinetics of the (UV-)chelate-modified Fenton processes
on the treatment of OSPW.
In the first stage, this research focused on the optimization of the NTA- and EDDS-
Fenton processes in the degradation of cyclohexanoic acid (CHA), a model NA compound. The
final CHA removal under the optimum conditions was 87% for NTA-Fenton and 64% for
EDDS-Fenton. Hydroxyl radical (•OH) was the main radical responsible for the CHA removal in
both processes, while superoxide radical (•O -) played a minor role. Oxy-CHA, hydroxyl-CHA,
2
and dihydroxyl-CHA were detected as the CHA oxidation products. The second-order rate
constants of •OH with CHA, NTA, and EDDS at pH 8 were investigated and obtained as
4.09±0.39×109, 4.77±0.24×108, and 2.48±0.43×109 M-1s-1, respectively. The consecutive addition
of hydrogen peroxide (H O ) and Fe-EDDS in the EDDS-Fenton process led to a higher removal
2 2
of CHA compared with adding the reagents at a time. However, the H O dosing mode in the
2 2
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NTA-Fenton process did not have a significant impact on the CHA removal. The mechanisms of
Fe(II) oxidation and Fe(III) reduction in the NTA/EDDS-Fenton processes were proposed and
discussed based on the redox potentials of Fe(III/II)NTA, Fe(III/II)EDDS, O /O •-, and H O /O •-.
2 2 2 2 2
In the second stage of the research, UV irradiation was applied in different processes at
pH 3 and 8. Compared to UV-H O , Fenton, UV-Fenton, NTA-Fenton, and UV-Fe-NTA
2 2
processes, UV-NTA-Fenton at pH 3 exhibited the highest efficiency for the H O decomposition,
2 2
CHA removal, and NTA degradation. H O -Fe(III)NTA adduct was related to the high amount
2 2
of Fe in the UV-NTA-Fenton system at pH 8 compared to that in the UV-Fe-NTA system. The
co-complexing effect of borate buffer helped to keep iron soluble at pH 8; however, it imposed a
negative influence on the CHA degradation in the UV-NTA-Fenton process.
In the third stage of the research, the removals of phenol and hydrogen sulfide (H S) as
2
toxic contaminants in OSPW were investigated. Tetrapolyphosphate (TPP) is a chelating agent
of iron and the catalytic ability of Fe(III)TPP in the oxidation of H S was investigated. The
2
formation of Fe(III)TPP-HS- intermediate in the reaction of Fe(III)TPP and HS- was proposed.
The second-order rate constant of the direct reaction between Fe(III)TPP and HS- at pH 9 was
obtained as 4.36±0.17 M-1s-1. The oxidation of Fe(II)TPP by O followed a four-step reaction
2
mechanism, and the reaction kinetic parameters were calculated based on the half-wave potential
(E ) of Fe(III/II)TPP. Low level of phenol degradation was found in the Fe(III)TPP-catalytic
1/2
desulfurization process.
At the end of the research, the application of the UV-NTA/EDDS-Fenton processes in the
treatment of OSPW at natural pH was investigated. The photodecomposition of Fe(III)NTA and
Fe(III)EDDS under UV irradiation in MilliQ water and OSPW was described and compared.
UV-NTA-Fenton exhibited higher efficiency than UV-EDDS-Fenton in the removal of acid
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extractable organic fraction and aromatics. NAs removal in the UV-NTA-Fenton process was
much higher than that in the UV-H O and NTA-Fenton processes. Both UV-NTA-Fenton and
2 2
UV-EDDS-Fenton presented promoting effect on the acute toxicity of OSPW towards Vibrio
fischeri. No significant change of the NTA toxicity occurred during the photolysis of Fe(III)NTA;
however, the acute toxicity of EDDS towards Vibrio fischeri increased as the photolysis of
Fe(III)EDDS proceeded. Considering the contaminants removal and the toxicity effect, NTA is a
much better agent than EDDS for the application of UV-Fenton process as a very promising
approach for OSPW remediation, and the process deserves more in-depth research on the toxicity
depletion and organics removal.

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PREFACE
All of the research in this thesis was designed and conducted by myself and supervised
by Professor Mohamed Gamal El-Din at the University of Alberta.
Chapter 2 consists of the contents of a journal article published in Chemical Engineering
Journal, 292 (2016) 340-347. The contribution of the coauthor is as follows:
 Dr. Nikolaus Klamerth contributed to the experimental plan and manuscript edits.
Chapter 3 contains the contents of a journal article submitted to the Journal of Hazardous
Materials. The contributions of the coauthors are as follows:
 Dr. Nikolaus Klamerth contributed to the experimental plan and manuscript edits.
 Dr. Selamawit Ashagre Messele contributed to the manuscript edits.
 Dr. Pamela Chelme-Ayala contributed to the manuscript edits.
 Mr. Béla Reiz from the Department of Chemistry at the University of Alberta contributed
to the detection of the CHA degradation products.
 Dr. Ted Sargent’s group from the Department of Electrical and Computer Engineering at
the University of Toronto contributed to the measurement of half-wave potentials.
Chapter 4 is an adaptation of a journal article, which has been submitted to the Journal of
Hazardous Materials. The contributions of the coauthors are as follows:
 Dr. Nikolaus Klamerth contributed to the manuscript edits.
 Dr. Pamela Chelme-Ayala contributed to the manuscript edits.
 Ms. Jing Zheng from the Department of Chemistry at the University of Alberta
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contributed to the measurement of CHA.
Chapter 5 presents the results for a journal article, which will be submitted to Applied
Catalysis B: Environmental. The contributions of the coauthors are as follows:
 Dr. Ali Safarzadeh-Amiri contributed to the experimental plan and manuscript edits.
 Dr. Nikolaus Klamerth contributed to the manuscript edits.
 Dr. Pamela Chelme-Ayala contributed to the manuscript edits.
 Dr. Ted Sargent’s group from the Department of Electrical and Computer Engineering at
the University of Toronto contributed to the measurement of half-wave potentials.
Chapter 6 consists of the contents for a journal article, which will be submitted to
Environmental Science & Technology. The contributions of the coauthors are as follows:
 Dr. Nikolaus Klamerth contributed to the manuscript edits.
 Dr. Pamela Chelme-Ayala contributed to the manuscript edits.
 Dr. Rongfu Huang contributed to the measurement of naphthenic acid.
 Mr. Guangcheng Chen from the Department of Earth & Atmospheric Sciences at the
University of Alberta contributed to the measurement of metal ions.
 Dr. Ted Sargent’s group from the Department of Electrical and Computer Engineering at
the University of Toronto contributed to the measurement of half-wave potentials.
 Mr. Mark Miskolzie from the Department of Chemistry at the University of Alberta
contributed to the NMR analysis.

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All the research work was done by myself except the above mentioned contributions
from the coauthors.

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DEDICATION
This work is dedicated to my lovely father, mother, other relatives, and my dear friends
who influence me in a great way.

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ACKOWLEDGEMENTS
First and foremost, I would like to express my great appreciation to my supervisor Dr.
Gamal El-Din for taking me into the group and for his kindness, support, patience and
supervision for the last three years. I also want to thank him for providing me a wonderful
internship experience. I would not be able to proceed through the doctoral program and complete
my dissertation without his priceless advice and encouragement.
I am deeply grateful to Dr. Nikolaus Klamerth, who gave me valuable suggestions and
enormous support during this research. He helped me to think as a researcher and to express my
ideas in a clear and concise manner. He reviewed all of my papers and I benefitted a lot from his
comments and advice. Thanks to Dr. Yanyan Zhang, my dear sister, who encouraged me a lot
and helped me out of glooms every time I felt stressed and depressed. Her kindness and patience
always calmed me down. I could not imagine what my life would be like without her.
Truly thanks to Dr. Pamela Chelme-Ayala for reviewing all of my papers, submitting
them to the journals, and helping me with the replies to reviewers. Moreover, she gave me
valuable suggestions for the thesis preparation. I greatly appreciate everything she did for me. I
also would like to thank Miss Maria Demeter and Miss Nian Sun, who taught me many things at
the beginning of my project.
I also want to thank Dr. Ali Safarzadeh-Amiri from Trojan Technologies, who supervised
me in my internship and gave me some precious advice. Thank Miss Shimiao Dong for helping
me doing some experiments. Thanks also go to all the staff in the Department of Civil and
Environmental Engineering who made it possible for me to complete my Ph.D. program.
I really acknowledge the support from my dear friends Jingkai Xue, Chunkai Huang,
Chengjin Wang, Chao li, Yuan Chen, Shimiao Dong, and Gaoteng Fan. They brought me so
many joys and were always around when I needed help.
Special thanks to my father Jikui Zhang, mother Zhaoping Cui, and brother Fuqiang
Zhang for their support, understanding, and encouragement, which means everything to me.
I am very grateful for a generous Ph.D. Student Scholarship (2012-2016) from China
Scholarship Council.
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This research was supported by a research grant from a Natural Sciences and Engineering
Research Council of Canada (NSERC) Senior Industrial Research Chair (IRC) in Oil Sands
Tailings Water Treatment through the support by Syncrude Canada Ltd., Suncor Energy Inc.,
Shell Canada, Canadian Natural Resources Ltd., Total E&P Canada Ltd., EPCOR Water
Services, IOWC Technologies Inc., Alberta Innovates - Energy and Environment Solution, and
Alberta Environment and Parks. The financial supports provided by Trojan Technologies and an
NSERC Collaborative Research and Development (CRD) grant are also acknowledged.

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