Effect of the fractionation and immobilization on the sorption properties of humic acid [Elektronische Ressource] / vorgelegt von Moustafa Khalaf

Moustafa Khalaf

Informations

• Publié par: rheinisch-westfalischen_technischen_hochschule_-rwth-_aachen
• Publié le: 01 janvier 2003
• Nombre de lectures: 8
• Langue: English
• Poids de l'ouvrage: 3 Mo

Extrait

“Effect of the fractionation and immobilization
on the sorption properties of humic acid”


Von der Fakultät für Mathematik, Informatik und Naturwissenschaften der
Rheinisch-Westfälischen Technischen Hochschule Aachen zur Erlangung des
akademischen Grades eines Doktors der Naturwissenschaften genehmigte
Dissertation




vorgelegt von

M.Sc. Chemiker
Moustafa Khalaf
aus Al-Minia, Ägypten


Berichter: Universitätsprofessor Dr. Dr. h. c. M. J. Schwuger
(Heinrich-Heine Universität Düsseldorf)

Universitätsprofessor Dr. A. Schäffer






Tag der mündlichen Prüfung: 24. März 2003



Diese Dissertation ist auf den Internetseiten der Hochschulbibliothek
online verfügbar. Acknowledgments

I wish to express my sincere appreciation and gratitude to Prof. Dr. Dr. h. c.
Milan J. Schwuger, director of the Institute of Applied Physical Chemistry,
Research Center Jülich, for supervising this work and for the attention he paid
to me during my studies.

Gratitude is due to Prof. Dr. A. Schäffer, Prof. of Environmental Chemistry,
Institute for Molecular Biology and Applied Ecology, University of Technology
Aachen, for his sincere assistance and for his acceptance to be my
co-examiner.

I would like to thank Professor Dr. H. Vereecken, director of the Institute of
Chemistry and Dynamics of the Geosphere IV: Agrosphere, Research Center
Jülich, for giving me the opportunity to complete my Ph.D. work in his institute
and for his support and interest on the progress of my research.

I am deeply grateful for the overwhelming guidance, support and excellent
supervision I have received from Dr. Erwin Klumpp, Institute of Chemistry and
Dynamics of the Geosphere IV: Agrosphere, Research Center Jülich. His
intuition and knowledge have never ceased to amaze me. He provided me
with many opportunities for invaluable scientific and personal experiences. He
created always a friendly and stimulating atmosphere that made me enjoy my
work very much.

I would like to thank Dr. H.-D. Narres very much for giving me the opportunity
to pursue my studies in the physicochemical soil functions group at the
institutes of “Chemistry and Dynamics of the Geosphere” and “Applied
Physical Chemistry”. I am also much indebted to him, on whose competent
advice and most efficient help I could always rely.

I am very grateful to Prof. Dr. J. Rice and Dr. S. Kohl, Department of
Chemistry and Biochemistry, South Dakota State University, for introducing me to the world of NMR spectroscopy and for their hospitality during my
unforgettable visit to Brookings, USA.

Sincere thanks are due to Dr. E. Tombácz, Department of Colloid Chemistry,
University of Szeged, whose helpful comments and suggestions have had a
considerable impact on this thesis and for her hospitality during my visit to
Szeged, Hungary.

I would like to thank Dr. E. Koglin for performing the “ab initio” calculations
and his useful discussion to interpret the FT-IR spectra. Thank you also for
Dipl.-Ing. H. Schlimper for performing the FT-IR measurements.

For the nice working atmosphere and the warmhearted helps and valuable
discussions, I am grateful to my colleagues in the physicochemical soil
functions group at the institutes of “Chemistry and Dynamics of the
Geosphere” and “Applied Physical Chemistry”. Special thanks to:
A. Muren, who helped me get started in laboratory,
A. de Nijs and A. Csiszar for their sense of humor and for being not only
colleagues but also good friends.

No words are sufficient to thank my wonderful and beautiful wife “Naglaa”.
The patience, love, sacrifice, encouragement, care and support freely given
by her which I experienced during my study were invaluable and made all the
difference. The youthful spirit of our son “Hazem” gave me the energy and
perspective to finish this work.

Last but not least, I would like to thank my parents and my sisters for their
love and their unconditioned and never-ending support of whatever will make
me happy. As a whole, my family has taught me the things that are truly
important in life: faith, love, and integrity. Thank you. CONTENTS
             

Contents


1. Introduction ……………………………………………….…………… 1

2. Outline of this thesis …………………………………….…………... 4

3. Theoretical background ……………………………..……………… 6

3.1. Humic substances in the environment …………………………. 6
3.2. Extraction and separation of soil humic substances …..……... 8
3.3. The structural concepts of humic acid …...………………..…… 10
3.4. Polyelectrolyte properties of humic acids ……………………… 11
3.5. Fractionation of humic acid …...…………………………………. 12
3.6. Adsorption isotherms ………………….…………………………. 13
3.7. Binding mechanisms of the natural and synthetic amphiphilic
macromolecules with the soil mineral particles ..……………… 15
3.7.1. Adsorption of polyelectrolytes ..…………………………… 15
3.7.2. Adsorption of humic acid ...………………………………… 17
3.8. Sorption mechanisms of hydrophobic organic compounds ..… 20

4. Materials and methods ……………………………………………… 24

4.1. Materials …………………………………………………………… 24
4.1.1. Humic acid …………………………………………………... 24
4.1.1.1. Extraction of humic acid ……………………………. 24
4.1.1.2. Fractionation of humic acid ………………………... 26
4.1.2. Polyacrylic acid ……………………………………………... 27
4.1.3. Organic chemicals ………………………………………….. 28
4.1.4. Aluminum oxide ……….……………………………………. 28
4.2. Methods …………………………………………………………… 29
4.2.1. Analytical methods …………………………………………. 29
4.2.1.1. Polyelectrolyte titration technique ………………… 29
4.2.1.2 Potentiometric acid-base titration …………………. 31
i CONTENTS
             

4.2.1.3. UV-VIS spectroscopy ………………………………. 33
4.2.1.3.1. Determination of E /E ……………….. 33465 665
4.2.1.3.2 Determination of 2,4-DCP ……………….. 33
4.2.1.4. FT-IR spectroscopy ………………………………… 34
4.2.1.5. NMR spectroscopy …...…………………………….. 34
13 4.2.1.5.1. C-NMR spectroscopy ...………………… 34
19 4.2.1.5.2. 35F-NMR spectroscopy ..………………..
4.2.1.6. Electrophoretic measurements ……………………. 36
4.2.1.7. Dynamic light scattering ……………………………. 37
4.2.1.8. Elemental analysis ………………………………….. 38
4.2.2. Adsorption measurements ………………………………… 38
4.2.2.1. Adsorption of organic macromolecules on
aluminum oxide ……………………………………... 38
4.2.2.1.1. Adsorption of humic acid ..……………….. 38
4.2.2.1.2. of polyacrylic acid …………… 39
4.2.2.2. Adsorption of 2,4-DCP on HA/Al O complex …… 392 3

5. Results and discussion 42

5.1. Materials characterization 42
5.1.1. Characterization of the organic macromolecules ……….. 42
5.1.1.1. Acid-base properties of polyacrylic acid ………….. 42
5.1.1.2. Acid-base properties of humic acid ……………….. 44
5.1.1.3. Fractionation of humic acid and elemental
composition of the fractions ...……………………... 45
5.1.1.4. Acid-base properties of humic acid fractions ……. 47
5.1.1.5. Spectroscopic characterization of humic acid and
its fractions ...…………………………………..……. 49
5.1.1.5.1. UV-VIS spectroscopy ……………..…..….. 49
5.1.1.5.2. FT-IR spectroscopy ……..………….…….. 51
13 5.1.1.5.3. C-NMR spectroscopy …………………… 57
5.1.2. Surface charge characterization of aluminum oxide .…… 60
ii CONTENTS
             

5.2. Evaluation of the sorption properties of hunic acid and its
19fractions based on F-NMR spectroscopy ….………………… 61
5.3. Interaction between organic macromolecules and alumina …. 68
5.3.1. Adsorption of polyacrylic acid on alumina ……………….. 69
5.3.2. Adsorption of humic acid on alumina …………………….. 73
5.3.3. Adsorption of humic acid fractions on alumina ………….. 79
5.3.4. Colloidal stability and electrophoretic mobility …………... 81
5.4. Interactions between 2,4-Dichlorophenol and HA/Al O 2 3
complexes ……………………………………………………….... 87
6. Summary ………………………………………..……………………... 94
7. References …………………………………………………………….. 97
8. List of figures …………………………………………………….…… 109
9. List of tables ………………………………..…………………………. 113

iii Chapter 1 INTRODUCTION
             

1 Introduction

Humans have always built up their own order at the expense of some order in
the environment; in recent history, however, they have multiplied destruction
of environmental order to build up increasingly intricate structure of cultural
and technical civilization (1). Increasing development of civilization has always
been a primary driving force for humans, and has been particularly enhanced
by men’s unmatched ability to exploit natural resources. However, it has
become evident in the past