enhancement of solubilization and sorption behaviors of polycyclic aromatic hydrocarbons through ...

268 Pages·2013·1.83 MB·English

ENHANCEMENT OF SOLUBILIZATION AND SORPTION
BEHAVIORS OF POLYCYCLIC AROMATIC HYDROCARBONS
THROUGH INVOLVEMENT OF GEMINI SURFACTANTS IN
SOIL-WATER SYSTEMS

A Thesis
Submitted to the Faculty of Graduate Studies and Research
In Partial Fulfillment of the Requirements
For the Degree of
Doctor of Philosophy
in
Environmental Systems Engineering
University of Regina

By
Jia Wei
Regina, Saskatchewan
April, 2013
Copyright 2013: J. Wei
UNIVERSITY OF REGINA

FACULTY OF GRADUATE STUDIES AND RESEARCH

SUPERVISORY AND EXAMINING COMMITTEE

Jia Wei, candidate for the degree of Doctor of Philosophy in Environmental Systems
Engineering, has presented a thesis titled, Enhancement of Solubilization and Sorption
Behaviors of Polycyclic Aromatic Hydrocarbons Through Involvement of Gemini
Surfactants in Soil-Water Systems, in an oral examination held on April 5, 2013. The
following committee members have found the thesis acceptable in form and content, and
that the candidate demonstrated satisfactory knowledge of the subject material.

External Examiner: *Dr. Huining Xiao, University of New Brunswick

Supervisor: Dr. Guo H. Huang, Environmental Systems Engineering

Committee Member: Dr. Guoxiang Chi, Department of Geology

Committee Member: Dr. Liming Dai, Industrial Systems Engineering

Committee Member: Dr. Stephanie Young, Environmental Systems Engineering

Chair of Defense: Dr. Dongyan Blachford,
Faculty of Graduate Studies and Research

*participated Video Conference
ABSTRACT

Contamination of soil, sediment and water by polycyclic aromatic hydrocarbons
(PAHs) has been recognized as a major, widespread, environmental waste concern. As a
consequence, surfactant enhanced remediation (SER) has emerged as a promising
technology for the removal of toxic PAHs. Gemini surfactants as a new generation of
surfactants have structures and properties that are unique to the world of surfactants,
such as greater efficiency in reducing surface tension and unusual aggregation
morphologies in comparison with conventional surfactants. They have generated a
growing interest owing to their superior performance in soil and water remediation
applications.
In this research, systematic studies have been physicochemically investigated in
detail via tensiometric, conductometric and solubilization techniques to get insight into
the micellar, interfacial and enhanced solubilization aspects of selected single and
equimolar bi and ternary Gemini/Gemini and Gemini/conventional surfactant systems. A
variety of mutual interaction parameters associated with the micellarization and
solubilization process have been correlated through several theoretical treatments to
understand the synergism and antagonism in solubilization capabilities of multi-
component surfactant systems. Nonideality has been found due to a change in the
microenvironment of the surfactant solution when various surfactants are mixed. The
results have shown the solubilization power depends on the micellar and interfacial
properties of the surfactant and their association with the hydrophilic/hydrophobic
properties of solutes.
i
Based on the solubilization analysis, the binding of select symmetric and
dissymmetric Gemini surfactants with soil particles and their equilibrium distribution
between solid and aqueous phases were evaluated. The adsorption isotherm is plotted
and modeled to measure the surface coverage by surfactant molecules under a given
condition to study the adsorption mechanism and, hence, determine the interfacial
properties of modified solids. The sorption capacity of modified soils and natural soils
and the overall partitioning of representative polycyclic aromatic hydrocarbons (PAHs)
in a soil-water-surfactant system with a soil-sorbed Gemini surfactant and Gemini
micelles are compared and related coefficients are developed.
Major contributions coming from this research include: 1) A set of methodologies to
evaluate and assist in the design of multi-component Gemini surfactant systems to
enhance the solubility of polycyclic aromatic hydrocarbons (PAHs); 2) A clearer view of
the effect of the structure of surfactants including the hydrophilic head group,
hydrophobic chain length and spacer length, and the chemical nature of the solute on the
micellar, interfacial and solubilization properties of surfactant systems; 3) Optimum
Gemini surfactant mixtures for potential engineering application; 4) An explanation of
the contaminant distribution pattern produced by the behavior of Gemini surfactant
adsorption onto soils; 5) An investigation into the partitioning behavior of PAHs in a
soil-water-Gemini surfactant and a development of the relative coefficients to produce an
in-depth understanding of the mechanisms for surfactant enhanced remediation
technology. The outputs of this study will be useful to understand and predict the
solubilization and adsorption properties of Gemini surfactant systems and provide proof
for exploring new surfactant systems for practical engineering applications.
ii
ACKNOWLEDGEMENTS

First and foremost, I am deeply grateful to my honorific supervisor, Dr. Gordon
Huang, for his patient supervising and generous support during the course of my Ph.D.
study. I have been extremely lucky to have a supervisor who cared so much about my
work and responded to my questions and queries so promptly. His positive outlook and
confidence in my research inspired me and gave me confidence. I have learned a lot from
him, without his help I could not have finished my dissertation successfully.
My great gratitude must also extend to his family, particularly to Ms. Chunling Ke,
for her kind help during my study while living in Regina.
I am grateful to the Faculty of Graduate Studies and Research and the Faculty of
Engineering and Applied Science at the University of Regina, for providing various
scholarships and awards for my Ph.D. study.
I would like to extend great thanks to my friends in the Environmental Informatics
Laboratory, Hui Yu, Shan Zhao, Yao Yao, Renfei Liao, Ping Guo, Yongping Li,
Xianghui Nie, Wei Chen, Gongchen Li, Yumin Chen, Xiaodong Zhang, Yanpeng Cai,
Qian Tan, Wei Sun, Zhong Li, Jiapei Chen, Xiujuan Chen, Yurui Fan, Guanhui Chen,
Xiuquan Wang, Sheng Li, Mengyuan Wang, Shuo Wang, Yang Zhou, and Hua Zhu, for
their friendships and unselfish helps during my Ph.D. study, which led to an enjoyable
and precious time in my life.

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DEDICATION

This dissertation is dedicated to my entire family, who gave me love, strength and
support throughout this important period of my life.
I am very grateful for my parents in China, Mr. Hua Wei and Ms. Bin Kong, for their
endless love and unconditional support. Their firm and kind-hearted personality has
affected me to be steadfast and never bend to difficulty. They always let me know that
they are proud of me, which motivates me to work harder and do my best.
Many appreciations are also due to my parents-in-law, Mr. Zixin Zhang and Ms.
Yimei Zhu, for their kind understanding and encouragement.
My deepest gratitude must be reserved for my husband, Lei Zhu. He took every
responsibility and suffered all the bitterness to take care of my family and our parents.
Without his understanding, support, encouragement and sacrifices, all that I have
achieved would have been impossible. I owe my every achievement to him.
Last but not the least, I am thankful to my dear grandparents who gave me strength,
courage and endless love.

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TABLES OF CONTENTS

ABSTRACT ...................................................................................................................... i
ACKNOWLEDGEMENTS............................................................................................. iii
DEDICATION .................................................................................................................. iv
CHAPTER 1 INTRODUCTION ..................................................................................... 1
1.1 Background.............................................................................................................. 1
1.2 Challenges ............................................................................................................... 4
1.3 Objectives ................................................................................................................ 8
1.4 Organization .......................................................................................................... 10
CHAPTER 2 LITERATURE REVIEW ...................................................................... 11
2.1 Research Regarding Surfactants ............................................................................ 11
2.2 Surfactant Solubilization ....................................................................................... 20
2.3 Surfactant Sorption ................................................................................................ 24
2.4 Applications of Surfactants for Soil and Water Remediation ............................... 30
2.5 Literature Review Summary.................................................................................. 41
CHAPTER 3 EFFICIENCY OF GEMINI SURFACTANT ON THE
SOLUBILIZATION OF PAHS IN COMPARISON WITH
CONVENTIONAL SURFACTANTS ................................................... 43
3.1 Introduction ........................................................................................................... 43
3.2 Materials and Methods .......................................................................................... 45
3.3 Results and Discussion .......................................................................................... 53
3.3.1 Surface properties of selected surfactants ................................................ 53
3.3.2 Solubilization by surfactants..................................................................... 57
3.4 Summary................................................................................................................ 69
CHAPTER 4 INVESTIGATION ON THE SOLUBILIZATION OF PAHS IN THE
PRESENCE OF SINGLE AND BINARY GEMINI SURFACTANT
SYSTEMS WITH VARIOUS HYDROPOBIC CHAIN LENGTHS . 71
4.1 Introduction ........................................................................................................... 71
4.2 Materials and Methods .......................................................................................... 74
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4.3 Results and Discussion .......................................................................................... 81
4.3.1 Critical micelle concentration properties of the single and equimolar
binary Gemini surfactants ....................................................................... 81
4.3.2 Solubilization of PAHs by single Gemini surfactants ............................... 84
4.3.3 Solubilization of PAHs by equimolar binary Gemini surfactants ............ 90
4.4 Summary............................................................................................................. 102
CHAPTER 5 ENHANCED SOLUBILIZATION CAPABILITIES OF BI AND
TERNARY CATIONIC GEMINI AND CONVENTIONAL
NONIONIC SURFACTANTS TOWARDS PAHS ............................ 104
5.1 Introduction ......................................................................................................... 104
5.2 Materials and Methods ........................................................................................ 107
5.3 Results and Discussion ........................................................................................ 113
5.3.1 Critical micelle concentration properties of all surfactant systems ....... 113
5.3.2 Surfactant-Surfactant interactions in mixed micelles ............................. 114
5.3.3 Solubilization of naphthalene and pyrene .............................................. 120
5.4 Summary.............................................................................................................. 133
CHAPTER 6 IMPROVED SOLUBILITIES OF PAHS BY MULTI-
COMPONENT GEMINI SURFACTANT SYSTEMS WITH
VERIOUS SPACER LENGTHS.......................................................... 134
6.1 Introduction ......................................................................................................... 134
6.2 Materials and Methods ........................................................................................ 136
6.3 Results and Discussion ....................................................................................... 142
6.3.1 Critical micelle concentration properties and surfactant-surfactant
interactions ............................................................................................ 142
6.3.2 Counterion binding ................................................................................. 148
6.3.3 Properties at the air/water interface ...................................................... 153
6.3.4 Solubilization abilities of selected surfactant systems towards PAHs.... 154
6.4 Summary.............................................................................................................. 164
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CHAPTER 7 GEMINI SURFACTANT-ENHANCED ADSORPTION AND
DESORPTION OF PAHS IN A SOIL-WATER-SURFACTANT
SYSTEM................................................................................................. 166
7.1 Introduction ......................................................................................................... 166
7.2 Materials and Methods ........................................................................................ 169
7.3 Results and Discussion ........................................................................................ 175
7.3.1 Sorption of Gemini surfactants ............................................................... 175
7.3.2 Solubilization of naphthalene by Gemini surfactants ............................. 178
7.3.3 Mobility of naphthalene in soil-water-Gemini surfactant systems ......... 182
7.3.4 Immobilization of naphthalene with Gemini surfactants ........................ 183
7.4 Summary.............................................................................................................. 191
CHAPTER 8 DISTRIBUTION OF PAHS IN A SOIL-WATER SYSTEM
CONTAINING A GEMINI SURFACTANT ...................................... 192
8.1 Introduction ......................................................................................................... 192
8.2 Materials and Methods ........................................................................................ 195
8.3 Results and Discussion ........................................................................................ 200
8.3.1 Solubilization of PAHs in the presence of Gemini surfactant ................ 200
8.3.2 Gemini surfactant sorption onto soil ...................................................... 206
8.3.3 Distribution of PAHs in a soil-water-surfactant system ......................... 209
8.4 Summary.............................................................................................................. 223
CHAPTER 9 CONCLUSIONS .................................................................................... 224
9.1 Summary.............................................................................................................. 224
9.2 Achievements ...................................................................................................... 226
9.3 Recommendations for Future Work .................................................................... 227
REFERENCES .............................................................................................................. 229

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LIST OF TABLES

Table 2.1 Size limits of different soil constituents (Paria, 2008) ...................................... 35
Table 3.1 The formula and physicochemical properties of the selected surfactants ......... 46
Table 3.2 Experimental critical micelle concentration (CMC ), ideal critical micelle
exp
concentration (CMC ), interaction parameter (β), micellar mole fraction (X)
mi i
and activity coefficients (f) values of equimolar surfactant mixtures at 25 ◦C a 54
i
Table 3.3 MSR, Log K , G0, R and B of phenanthrene in various single and equimolar
m s
mixed micellar systems at 25 ◦C a ...................................................................... 67
Table 4.1 The formula, molecular properties and experimental critical micelle
concentrations (CMC ) of the selected Gemini surfactants ............................. 75
exp
Table 4.2 The formula and physicochemical properties of the selected PAHsa ............... 76
Table 4.3 Experimental critical micelle concentration (CMC ), ideal critical micelle
exp
concentration (CMC ), interaction parameter (β), micellar mole fraction (X),
mi i
ideal micellar mole fraction (X ) and activity coefficients (f) values of
ideal i
equimolar Gemini mixtures at 25 ◦C a ................................................................ 83
Table 4.4 Log K , Log K , G0, R and B of PAHs in various equimolar mixed Gemini
m m12 s
surfactant systems at 25 ◦C a ............................................................................. 101
Table 5.1 The structure and physicochemical properties of the selected surfactants and
solutesa in this study ........................................................................................ 110
Table 5.2 Experimental critical micelle concentration (CMC ), ideal critical micelle
exp
concentration (CMC ), interaction parameter (β), micellar mole fraction (X)
mi i
and activity coefficients (f) values of equimolar surfactant mixtures at 25 ◦C a117
i
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