TABLE OF CONTENTS
Title Page .. .. .. .. .. .. .. .. .. .. .. i
Certification .. .. .. .. .. .. .. .. .. .. ii
Dedication .. .. .. .. .. .. .. .. .. .. .. iii
Acknowledgment .. .. .. .. .. .. .. .. .. iv
Table of Contents .. .. .. .. .. .. .. .. .. v
List of Tables .. .. .. .. .. .. .. .. .. .. viii
List of Figures .. .. .. .. .. .. .. .. .. .. ix
List of Symbols ..      ..         ..         ..         ..         ..         ..         ..         x
List of Abbreviation ..             ..         ..         ..         ..         ..         xi
Abstract .. .. .. .. .. .. .. .. .. .. .. xii
CHAPTER ONE: INTRODUCTION
1.0 Background of Study .. .. .. .. .. .. .. .. 4
1.1 Heavy Metal Toxicity.. .. .. .. .. .. .. .. 4
1.2 Methods of Heavy Metal Removal .. .. .. .. .. .. 5
1.3 Types of Heavy Metal Adsorbents . .. .. .. .. .. 5
1.3.1 Zeolite .. .. .. .. .. .. .. .. .. .. 6
1.3.2 Use of Synthetic Zeolite for Wastewater Treatment .. .. .. 8
1.3.3 Mechanisms of Heavy Metal Removal from Industrial Waste Water .. .. 10
1.4 Adsorption .. .. .. .. .. .. .. .. .. .. 11
1.4.1 Adsorption Isotherms .. .. .. .. .. .. .. .. 12
1.5 Statement of the Problem .   ..       ..       ..       ..       ..       13
1.6 Objective of Study .. . .. .. .. .. .. .. .. 14
1.7 Justification of the Study .. .. .. .. .. .. .. .. 14
CHAPTER TWO
2.0 Literature Review .. .. .. .. .. .. .. .. .. 15
2.1 A Review of Zeolite Types used as Adsorbents .. .. .. .. 15
2.2 Adsorption of Heavy Metals using Zeolite .. .. .. .. .. 23
CHAPTER THREE
3.0 Reagents .. .. .. .. .. .. .. .. .. .. 29
3.1 Instrument/Apparati .. .. .. .. .. .. .. .. 29
3.2 Methods .. .. .. .. .. .. .. .. .. .. 30
3.2.0 Zeolite Synthesis .. .. .. .. .. .. .. .. .. 30
3.2.1 Preparation of Synthesis Gel .. .. .. .. .. .. .. 30
3.2.2 Crystallization Gel .. .. .. .. .. .. .. .. 30
3.2.3 Crystallization .. .. .. .. .. .. .. .. .. 31
3.2.4 Product Recovery .. .. .. .. .. .. .. .. .. 31
3.2.5 Product Characterization .. .. .. .. .. .. .. 31
3.2.6 Heavy Metal Determination .. .. .. .. .. .. .. 31
3.3 Freundlich and Langmuir Models .. .. .. .. .. .. 32
CHAPTER FOUR
4.0 Results and Discussion .. .. .. .. .. .. .. .. 35
4.1 Synthesis of Adsorbent .. .. .. .. .. .. .. .. 35
4.2 Characterization of Adsorbent .. .. .. .. .. .. .. 36
4.3 Adsorption of Heavy Metal Ion .. .. .. .. .. .. .. 37
4.3.1 Effect of Heavy Metal Ion Concentration .. .. .. .. .. 37
4.3.2 Effect of Adsorbent Dosage .. .. .. .. .. .. .. 40
4.3.3 Effect of Particle Size on Adsorption ..     ..       ..       ..       41
4.4 Adsorption Isotherms .. .. .. .. .. .. .. .. 43
CHAPTER FIVE
5.0 Conclusion .. .. .. .. .. .. .. .. .. .. 47
REFERENCES
APPENDIX
LIST OF TABLES
Table 1: Effect of Initial Ion Concentration on Extent of Adsorption (%) and Amount of Metal ion Adsorbed Per Unit Mass of Adsorbent (qe, mg/g) for Adsorption of Pb (II) on Zeolite .. ..         ..         ..         ..         ..         38
Table 2: Effect of Adsorbent Amount of Extent of Adsorption and Amount Adsorbent Par Unit Mass .. .. .. .. .. .. .. 41
Table 3: Test Carried out with 2g Adsorbent 60 Minute Shaking and 15ppm  Initial Metal ion Concentration ..  ..       ..       ..       ..       ..       42
LIST OF FIGURES
Fig 1: Hydrothermal Zeolite Synthesis .. ..        ..         ..         ..         33
Fig 2: PTFE Vessel with its Pressure Vessel used for Hydrothermal Synthesis of Zeolite 34
Fig. 3: SEM images showing the Synthesized Zeolite Nanocrystals …..       33
Fig 4: XRD Result showing the Pattern of the Crystalline Phase .. .. 35
Fig 5: Effect of Initial Metal Concentration on Extent of Adsorption ..39
Fig. 6: Effect of Adsorbent Amount on Adsorption of Pb Ions .. .. 43
Fig. 7:  Isotherm Plot of (qe vs Ce) for Adsorption of Pb(II)  ..     45
Fig.
8:
Langmuir and Frenundlich Isotherm Plots for Adsorption of Pb2+ .. 46
LIST OF SYMBOLS
°C Celcius
Ã… Angstron (1 x 10-10)
nm nanometer (1 x 10-9)
μm micrometer (1 x 10-6)
cm Centimeter (1 x 10-2)
cm3 Centimeter cube
mg milligram
g/l gram /liter
g/cm3 gram/centimeter cube
M
molar
LIST OF ABBREVIATION
NaOH Sodium Hydroxide
SiO2 Silicon dioxide
HCl Hydrochloric Acid
KOH Potassium Hydroxide
XRD X-ray Diffraction
SEM Scanning Electron Microscope
TEM Transmission Electron Microscope
SAC Steam Assisted Conversion
DGC Dry Gel Conversion
CEC Cation Exchange Capacity
VPT Vapor Phase Transport
FAU Faujasite
SOD Sodalite
GIS Gismondine
LTA Lynde Type A
HCFCs Hydrochloroflourocarbons
ABSTRACT
The removal of Pb(II) ions from aqueous model solution using zeolite has been investigated under different operational parameters like heavy metal ion concentration, adsorbent amount and particle size. The zeolite used was synthesized and characterized using SEM and XRD analysis. The equilibrium adsorption capacity of zeolite used for lead removal were measured and the experimental data analyzed by means of Freundlich and Langmuir isotherm models. The adsorption efficiency of Zeolite in removing Pb2+ ions at room temperature and 60 minute agitation time at pH<10 was 98%. The results also show that the adsorbent with the lowest particle size of 53.6µm had the highest adsorption efficiency(98.33%) The concentration of metal ions were measured by Atomic Absorption Spectroscopy (AAS). Overall, the results showed that synthetic zeolite could be considered as a potential adsorbent for lead removal from aqueous solutions.
CHAPTER ONE
INTRODUCTION
In developing countries, rapid growth of urbanization and industrialization has generated large volume of waste containing toxic heavy metals. Heavy metal contamination exists in aqueous waste water streams of many industries such as metal plating facilities, mining operations, tanneries etc1. Environmental pollution due to these toxic metals have been of major concern to environmental engineers; the ions from these heavy metals cause damage to humans e.g. cadmium poisoning causes acute chronic disorders such as renal damage and hypertension, problem in Haemoglobin synthesis, kidney, gastrointestinal tract, joints and reproductive disorders. Acute or chronic dosage results in damage of the nervous system2. Within the body, lead is absorbed and stored in the bones, blood, and tissues. It does not stay there permanently, rather it is stored there as a source of continual internal exposure 3. As time goes by, the bones demineralize and the internal exposures may increase as a result of larger releases of lead from the bone tissue. There is also concern that lead may mobilize from the bone among women undergoing menopause4. Post menopausal women have been found to have higher blood lead levels than pre-menopausal women5.
Lead poisoning occurs if a person is exposed to very high levels of lead over a short period of time. When this happens, a person may feel abdominal pain, constipated, tired, headachy, irritable, loss of appetite, memory loss, pain or tingling in the hands and/or feet and weak.
Generally, lend affects children more that it does adults. Children tend to show signs of sever lead toxicity at lower levels than adults. Neurological effects and mental retardation have also occurred in children whose parents may have job-related lead exposure6. The health effects from prolonged exposure to lead included abdominal pain, depression, forgetfulness among others. Also, the Department of Health and Human Services (DHHS), Environmental Protection Agency (EPA), and the International Agency for Research on cancer (IARC) have determined that lead is probably cancer-causing in human7.
