Application and evaluation of amine based polymers for heavy metals adsorption and recovery ...

185 Pages·2015·9.13 MB·English

Application and evaluation of amine based
polymers for heavy metals adsorption and
recovery from wastewater

Thesis submitted
in partial fulfillment of the requirements for the degree of
Doctor of Philosophy
by

Potsangbam Albino Kumar
Regd. No. 04610409

DEPARTMENT OF CIVIL ENGINEERING
INDIAN INSTITUTE OF TECHNOLOGY GUWAHATI
GUWAHATI-781039, INDIA
July 2009
Dedicated

to

My Loving Parents

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TH-824_04610409
CERTIFICATE

This is to certify that the thesis entitled “Application and evaluation of amine
based polymers for heavy metals adsorption and recovery from wastewater” submitted by
Potsangbam Albino Kumar (04610409) to the Indian Institute of Technology Guwahati
for the degree of Doctor of Philosophy is a record of bonafide research work carried out
by him under our supervision and guidance. The thesis work, in our opinion has reached
the requisite standard fulfilling the requirement for the degree of Doctor of Philosophy
and has not been submitted earlier for award of any degree or diploma to the best of our
knowledge and belief.

(Supervior) (Co Supervisor)
Dr. Saswati Chakraborty Dr. Manabendra Ray
Associate Professor Associate Professor
Department of Civil Engineering Department of Chemistry
Indian Institute of Technology Guwahati Indian Institute of Technology Guwahati

Guwahati
May, 2010

TH-824_04 610409 ii
Acknowledgement

The journey of this research work for the last four and half years has taught me
several principles of life. And through this phase, several individuals from different walk
of life have come upon to guide, help and support me. It is my privilege to acknowledge
those persons who have made the most conspicuous contribution for the completion of
my research work and who sought nothing in return from me.

Firstly, I thank my supervisor, Dr. Saswati Chakraborty, for the confidence she
placed in me for carrying out the research work. Working under her supervision and
being her first PhD student was a huge privilege with her teachings and guidance on
ethics of high quality research through her knowledge, understanding, patience,
dedications, sacrifice and inspiration. Her constant encouragement throughout the phase
of my research work with her complete involvement even during experimental period
was truly admiring. The effort she put in my research work was tremendous and complete
in all aspects and that taught me the essential qualities of being a dedicated guide.

I would like to gratefully and sincerely thank my co supervisor Dr. Manabendra
Ray, for his guidance, understanding, patience, and most importantly, his friendship
during the course of the research. His mentorship was paramount in providing a well
rounded experience for my long-term career goals. He encouraged me to not only grow
as an experimentalist but also as an instructor and an independent thinker.

I would like to express my sincere gratitude to my Doctoral committees, Dr.
Baleshwar, Dr. Sharad Ghokhale and Dr. Gopal Das for their constant directions and
guidance in moulding my research work. I would like to thank Prof. Talukdar and Prof.
Anjan Dutta (former HODs of Civil Engg. Dept) and Prof. S. K. Deb for their help and
the facilities provided for completion of the research work. I sincerely would like to
thank Dr. M. Jawed for the management skills he taught and trained me for being a future
academician, for his valuable advice, inspiration and encouragement.
TH-824_04 610409 iii
I appreciate and thanks the help rendered by Jonali Saikia (Scientific Officer) and
P. Pathak (Lab attendant) that makes my research experiment complete. I am very much
thankful to Jayshree Nath, Deepmoni Deka (Scientific Officer) and Partho (Lab
Technician), Center of Environment, IIT Guwahati, for their cooperation and help with
equipments and resource during my experimental period in their laboratory. I am very
grateful to my friends from Chemistry department, Rik, Ballav, Marjit, and Francis for
their valuable help in analysis of reactions and compounds for my research work. I would
like to express my gratitude to Mr. Plaubon Basu (Varian, Calcutta) for his help in
learning A.A.S. Instrument and also Center for instrument Facility (CIF), IIT Guwahati
and CDRI, Lucknow, for allowing analysis of my polymers and samples. The quality
level of research work achieved won’t be possible without the financial support of
Council of Scientific and Industrial Research (CSIR), Govt. of India, through project (No.
22 (0418)/06/EMR-II) and their support is hereby highly acknowledged.

This is a great opportunity to thank my fellow friends with whom I share my
pains, sorrows, fun and laughter throughout the whole phase of my research work in IIT
Guwahati. It will be impossible to imagine a life in campus without them. The help,
support and advice of my seniors and well wisher Dr. Manglem, Tejmani, Dr. Darun,
Kabita, Tej Banta, Dr. Girija, Sangeeta, Thoiba, Ashok, Bina are truly invaluable. I am
very much obliged to my friend G. Pramod for his tremendous help during my initial
phase of this research work. I will be very much indebted if I don’t thank my friends from
campus, Naim Hossain, Ramu Gantela, Zulker Nain, Biju Prava, Rupak Sarkar, Minaxi
Rai, Sachin, Sandip Mondal, Jyoti, Aashish, for their love and affection besides their
help, encouragement and support. Dr. Sarbajit, Arun Yendrembam, Genemala Hoabijam
and Sonia Nongmaithem, they are the wonderful individuals who keep on pouring
unconditional support professionally and personally throughout my stay in campus and
close to my heart, and I would like to thank them for their constant support. I specially
would like to thank my fellow colleagues Kamal Uddin Ahamad and Lalsangzela Sailo
who are more than a friend and brother, for the whole journey they had with me
throughout my stay in IIT Guwahati. I would like to highly acknowledge my fellow
friends Uttam, Deepak, Santosh, Bihari, Roshan, Joy Shanker, Hemjit, Gautam, Devson,
TH-824_04 610409 iv
Ronel and Hudson for their unwavering love, help, support and encouragement during
my research.

Most importantly, I would like to thank my loving sisters Dr. Lunalisa and Ruby
Miranda, my brother in law Anuj Shanker Saxena and Rahul Dev Sharma for their
unwavering love and affection, unending encouragement, support and guidance. I am
very much thankful to my wife Mimoda Devi. Her support, encouragement, quiet
patience and prayers since the beginning of my research work, were undeniably the
bedrock upon which the past four and half years of my life in research have been built.
The love and affection of my daughter Ichathoi (Jessica Potsangbam) and her desire to be
with me always is the main inspiration in completion of my Thesis. Finally, I thank my
parents, for their faith in me and allowing me to be as ambitious as I wanted. It was under
their watchful eye that I gained so much drive and an ability to tackle challenges head on.

Potsangbam Albino Kumar
TH-824_04 610409 v
Abstract

The impact of heavy metal pollution on environment due to industrial effluent is a global
concern. Adsorption technique is one of the well proven metal removal techniques due to its
several advantages over conventional methods like simple and easy operation, low cost,
recovery of metal ions etc. Employment of functionalized polymers containing several
functional groups such as amines, carboxylate, ether, hydroxyl, sulphate, phenolic, cyanide,
chloride, acetate etc., as adsorbent for removal of metal ions has become a recent trend.
However many of the reported functionalized polymers have complex synthesis procedure
and cost ineffective. Therefore development of low cost functional polymer with easy
synthesis procedure, moderate to high metal removal, rapid adsorption kinetics and
reusability is necessary.

Amine (-NH ) is known to be one of the most effective metal binding functional group
2
due to presence of lone pair of electron in sp3 hybridized atom of nitrogen. In the present
study, two amine based polymers namely aniline formaldehyde condensate (AFC) and
polyaniline (PANI) were synthesized to use as an adsorbent for metal removal from aqueous
solution. Aniline was used as the amine source for both the polymers. The obtained polymers
however being resinous, solid support were necessary to add in the matrixes of polymers to
make granular adsorbent for easy separation of metal-adsorbent after interactions between
metal and polymer. For AFC, due to its sticky nature, silica gel was observed as the only
suitable support, where as for PANI, jute fibre was selected as the support medium. Synthesis
of both the polymers was optimized in terms of metal removal efficiency. During interaction
with anionic metal ions hexavalent chromium, maximum removal was achieved by both AFC
coated silica gel and PANI-jute at pH 3 due to electrostatic attraction of protonated amines
(NH +) of polymer with chromate ion (HCrO −). On removal study of cationic metal ions,
3 4
removal trend of trivalent chromium [Cr(III)] and mercury [Hg(II)] by both the polymers and
copper [Cu(II)], cadmium [Cd(II)] and lead [Pb(II)] by PANI-jute trends were observed
similar with increase in metal removal with increase in pH. Maximum removals of all
cationic metal ions were observed in the pH range of 6-9. The main removal mechanism was
due to formation of coordinate bond between deprotonated nitrogen of amine (-NH ) in
2
polymers and cationic metal ions. AFC polymer showed presence of amine group throughout
the chain length of the polymer, whereas PANI had amine group only at the terminal end
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position. Due to presence of higher amount of amine group, AFC showed more metal uptake
(both cationic and anionic metals) than PANI. Desorption studies showed metal recovery of
70-100% by both the polymers for all metals except for Cr(III) due to the high kinetic
immobility of it. Since jute is combustible in nature, ignition of Cr(III) contaminated PANI-
jute reduced the volume of spent adsorbent by more than 95-99% solving the problem of
solid waste disposal as alternative. After desorption both the polymers were reused for several
cycles. Through this adsorption-desorption-adsorption process, AFC coated silica gel was
regenerated by chloroform extraction process and reused for four cycles with 80% metal
removal efficiency whereas PANI-jute could be reused by washing with distilled water for
more than six cycles without sacrificing metal removal efficiency. In industrial effluent, metal
ions hardly exist as single ions, but as mixture of metals. Therefore adsorption from mixed
metal system was studied with both AFC and PANI-jute and observed similar results with
adsorption in the order of Cu(II) > Ni(II) > Cr(III) > Hg(II) > Pb(II) > Cd(II). These mixed
metals removals followed the preferences dictated by the hard-soft theory of acids and bases
and ligand exchange rate of metal ions. Dynamic metal removal studies by column
experiments revealed the achievement of removal of highly toxic Hg(II) by AFC coated silica
gel and Cr(VI) by PANI-jute with effluent below the permissible limit of 0.05 µg/L for both
the metal ions. However, for AFC coated silica gel, column operation was more difficult as
compared to PANI-jute due to less permeability of the column bed. Effort was made to
synthesize AFC polymer without any support by increasing the amount of crosslinking agent
formaldehyde than aniline and introducing alcohols to create voids. During preliminary study,
support less AFC was observed to remove Cr(VI) more than double the amount adsorbed by
AFC coated silica gel and PANI-jute. However the synthesis procedure of support less AFC
was observed as highly sensitive with respect to temperature and effective size and further
studies are required to optimize this. Both AFC with and without support can be stored for six
months time without degradation in metal removal capacity whereas PANI-jute showed
stability during storage for as long as 40 months time period.

Keywords: Heavy metals; amine; polymer; adsorption; desorption; polyaniline.

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Table of Contents

Page No
Abstract vi
List of Figures x
List of Tables xiv
Nomenclature xviii
Chapter 1. Introduction 1- 3
Chapter 2. Literature Review 4- 33
2.1 Introduction 4
2.2 Toxicity 5
2.3 Sources 5
2.4 Guidelines 7
2.5 Removal techniques of heavy metals 8
2.5.1 Chemical precipitation 9
2.5.2 Ion exchange 9
2.5.3 Membrane Process 9
2.5.4 Adsorption 10
2.6 Scope and objective of the present study 31
Chapter 3 Materials and methods 34- 54
3.1 Materials 34
3.2 Polymer synthesis and adsorbent preparation 35
3.2.1 Synthesis of aniline formaldehyde condensate (AFC) coated
36
on silica gel
3.2.2 Synthesis of polyaniline polymer on surface of jute fibers 37
3.2.3 Synthesis of support less AFC modified with alcohols 38
3.3 Studies with metal ions 40
3.3.1 Batch mode experiments 40
3.3.2 Continuous column mode operation 41
3.3.3 Experimental protocol 42
3.4 Analytical techniques 52
Chapter 4 Results and discussion 55- 146
4.1 Studies with AFC 56
4.1.1 Synthesis and characterization of AFC coated on support 56
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materials
4.1.2 Performance of AFC polymer in heavy metal removal 61
4.1.3 Continuous column mode operation study 88
4.2 Studies with PANI-jute 93
4.2.1 Synthesis and characterization of PANI synthesized on
93
support materials
4.2.2 Removal of metal ions by PANI-jute in batch mode 97
4.2.3 Continuous column mode operation study 128
4.3 Studies with support less AFC 143
4.3.1 Characterization of support less AFC synthesized with
143
alcohols
4.3.2 Removal of Cr(VI) by support less AFC modified with
143
alcohol
Chapter 5 Conclusions 147- 151
Reference 152- 164
List of Publications 165- 166

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