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SYNTHESIS, CHARACTERIZATION, AND
THERMOPHYSICAL PROPERTIES OF MAGHEMITE
(-Fe2O3) NANOFLUIDS WITH AND WITHOUT
MAGNETIC FIELDS EFFECT
IRWAN NURDIN
FACULTY OF ENGINEERING
UNIVERSITY OF MALAYA
KUALA LUMPUR
2016
SYNTHESIS, CHARACTERIZATION, AND
THERMOPHYSICAL PROPERTIES OF MAGHEMITE
(-Fe2O3) NANOFLUIDS WITH AND WITHOUT
MAGNETIC FIELDS EFFECT
IRWAN NURDIN
THESIS SUBMITTED IN FULFILMENT OF THE
REQUIREMENTS FOR THE DEGREE OF DOCTOR OF
PHILOSOPHY
FACULTY OF ENGINEERING
UNIVERSITY OF MALAYA
KUALA LUMPUR
2016
ii
UNIVERSITY OF MALAYA
ORIGINAL LITERARY WORK DECLARATION
Name of Candidate: Irwan Nurdin (I.C/Passport No: A5747183)
Registration/Matric No: KHA 090058
Name of Degree: Doctor of Philosophy
Title of Project Paper/Research Report/Dissertation/Thesis (this Work):
Synthesis, Characterization, And Thermophysical Properties of Maghemite
(-Fe2O3) Nanofluids With And Without Magnetic Fields Effect
Field of Study: Nanomaterials
I do solemnly and sincerely declare that:
(1) I am the sole author/writer of this Work; (2) This Work is original; (3) Any use of any work in which copyright exists was done by way of fair dealing
and for permitted purposes and any excerpt or extract from, or reference to or
reproduction of any copyright work has been disclosed expressly and
sufficiently and the title of the Work and its authorship have been
acknowledged in this Work;
(4) I do not have any actual knowledge nor do I ought reasonably to know that the making of this work constitutes an infringement of any copyright work;
(5) I hereby assign all and every rights in the copyright to this Work to the University of Malaya (UM), who henceforth shall be owner of the copyright
in this Work and that any reproduction or use in any form or by any means
whatsoever is prohibited without the written consent of UM having been first
had and obtained;
(6) I am fully aware that if in the course of making this Work I have infringed any copyright whether intentionally or otherwise, I may be subject to legal action
or any other action as may be determined by UM.
Candidates Signature Date:
Subscribed and solemnly declared before,
Witnesss Signature Date:
Name:
Designation:
iii
ABSTRACT
Synthesis, characterization, and thermophysical properties of maghemite nanofluids
have been studied with and without magnetic fields effect. The objectives of study are to
synthesize maghemite nanoparticles and their characterization using various methods, to
prepare stable maghemite nanofluids, and measurement of thermophysical properties of
maghemite nanofluids with and without external magnetic fields effect. Maghemite
nanoparticles were synthesized by chemical co-precipitation method with different
concentrations of nitric acid. Maghemite nanofluids were then prepared and the stability
of the nanofluids were characterized by zeta potential and dynamic light scattering at
different pH and time of storage. Lastly, measurements of thermal conductivity, viscosity,
and electrical conductivity of maghemite nanofluids were taken at various particle
volume fraction, temperatures, with and without strengths of magnetic fields. Results
show that spherical shape of superparamagnetic maghemite nanoparticles with good
thermal and suspensions stability was successfully synthesized within the size range of
9.3 to 14.7 nm. The stability of maghemite nanofluids show that the suspensions remain
stable at acidic condition with zeta potential value of 44.6 mV at pH 3.6 and at basic
condition with zeta potential -46.2 mV at pH 10.5. The isoelectric point of the maghemite
nanoparticles suspensions is obtained at pH 6.7. The maghemite nanofluids remains
stable after eight months of storage. The thermal conductivity of maghemite nanofluids
linearly increases with increasing of particle volume fraction, temperature, and magnetic
fields strengths. The kinematic viscosity of maghemite nanofluids increases with
increasing of particle volume fraction and magnetic fields and decrease with increasing
of temperature. Electrical conductivity of maghemite nanofluids increases with increasing
of particle volume fraction and temperature and no effect with magnetic fields.
iv
ABSTRAK
Sintesis, pencirian, dan sifat termofizikal bendalir maghemite nano telah dikaji dengan
dan tanpa kesan medan magnet. Objektif kajian ini adalah untuk mensintesis zarah
maghemite nano dan menjalankan pencirian dengan menggunakan pelbagai kaedah,
menyediakan bendalir maghemite nano yang stabil, dan pengukuran ciri-ciri termofizikal
bendalir maghemite nano dengan dan tanpa pengaruh medan magnetik luaran. Sintesis
zarah maghemite nano dengan menggunakan kaedah co-pemendakan kimia. Kepekatan
asid nitrik yang berbeza digunakan sebagai pembolehubah, kemudian penyediaan
bendalir maghemite nano yang stabil yang dicirikan dengan mengukur keupayaan zeta
dan dynamic light scattering pada pH dan masa simpanan yang berbeza. Akhirnya,
pengukuran kekonduksian terma, kelikatan, dan kekonduksian elektrik bendalir
maghemite nano pada pelbagai suhu, kepekatan zarah maghemite nano, dengan dan tanpa
kekuatan medan magnetik luar. Hasil uji kaji menunjukkan superparamagnetik zarah
maghemite dengan bentuk sfera dan kestabilan haba dan suspensi yang baik dan saiz
dalam julat 9.3 14.7 nm telah berjaya dihasilkan. Bendalir maghemite nano yang stabil
menunjukkan ia berada di keadaan asid dengan nilai keupayaan zeta 44.6 mV pada pH
3.6 dan pada keadaan bes dengan nilai keupayaan zeta -46.2 mV pada pH 10.5. Takat
isoletrik pula di perolehi pada pH 6.7. Bendalir maghemite nano masih berada dalam
keadaan stabil selepas lapan bulan. Kekonduksian terma bendalir maghemite nano adalah
linear meningkat dengan peningkatan kepekatan zarah, suhu dan medan magnet.
Kelikatan kinematik bendalir maghemite nano adalah meningkat dengan peningkatan
kepekatan jumlah zarah dan medan magnet dan menurun dengan peningkatan suhu.
Manakala, kekonduksian elektrik adalah meningkat dengan peningkatan kepekatan zarah,
dan suhu dan tidak berkesan dengan medan magnet.
v
ACKNOWLEDGEMENTS
With deep regards and profound respect, I would like to express my sincere thanks and
gratitude toward Prof. Dr. Mohd Rafie Johan and Prof. Dr. Iskandar Idris Yaacob for
introducing the present research topic and for their inspiring guidance, constructive
criticism, and valuable suggestion throughout this research work. It would have not been
possible for me to bring out this thesis without their help and constant encouragement.
Special thanks to my colleague, Ms. Yusrini Marita, Mrs. Ang Bee Chin, Ms. Siti
Hajar, Mrs. Fatihah, Mr. Shahadan Mohd Suan, Mrs. Aliya, Mrs. Yusliza, Ms. Syima
Razali, Mrs. Asmalina, Mrs. Mariah and Ms. Nadia in sharing their knowledge and ideas
with me. Besides that, sincerest appreciation goes to Faculty of Engineering, University
of Malaya for providing all the facilities in the Mechanical Department and laboratories.
Not forgetting also, the dedicated laboratory assistant Mr. Mohd Said Sakat, Mr. K.
Kandasamy and Mr. Suhaimi, Mrs. Norzirah, and Ms. Aida Nur Izzaty for giving their
full co-operation while using the equipments.
Last but not least, awards of thanks to my father Nurdin Abidin (alm), my mother,
Nuriah Husin and lovely family members and my wife Mrs Nurliza Idris and my children
Thariq Irza and Tsaqif Aufa Irza who give me full support in making this research work
a success. Thanks for sharing my hard time.
Appreciate the efforts and contributions shared by individuals whose names are not
mentioned above.
Thank you so much.
vi
TABLE OF CONTENTS
Abstract iii
Abstrak iv
Acknowledgements.. v
Table of Contents.........vi
List of Figures ..ix
List of Tables..xiii
List of Symbols and Abbreviations..xv
List of Appendices.....xvii
CHAPTER I: INTRODUCTION...................................................................................1
1.1 Background..1
1.2 Problem Statement...3
1.3 Objectives.4
1.4 Research Scope and Limitation ...4
1.5 Significant of Research5
1.6 Thesis Organization.5
CHAPTER II: LITERATURE REVIEWS...7
2.1 Nanofluids7
2.1.1 Fundamental of nanofluids...7
2.1.2 Impact and potential benefit of nanofluids9
2.1.3 Potential application of nanofluids..10
2.2 Synthesis of Maghemite Nanoparticles .14
2.3 Application of Maghemite Nanofluids..17
2.3.1 Magnetic resonance imaging..17
2.3.2 Magnetic separation18
2.3.3 Nanocatalysis..19
vii
2.3.4 Thermal engineering...19
2.3.5 Environmental .......21
2.4 Magnetism and Magnetic Properties of Nanoparticles..22
2.5 Stability of Maghemite Nanofluids.29
2.6 Thermophysical Properties.32
2.6.1 Thermal conductivity..32
2.6.2 Viscosity.43
2.6.3 Electrical Conductivity...47
CHAPTER III: METHODOLOGY.........