batch and bench-scale fixed-bed column evaluations of heavy metal removals from aqueous ...

332 Pages·2008·4.77 MB·English

BATCH AND BENCH-SCALE FIXED-BED COLUMN
EVALUATIONS OF HEAVY METAL REMOVALS FROM
AQUEOUS SOLUTIONS AND SYNTHETIC LANDFILL
LEACHATE USING LOW-COST NATURAL ADSORBENTS

By

Chenxi Li

Thesis submitted to the Department of Civil Engineering in conformity with the
requirements for the degree of Master of Science (Engineering)

Queen’s University
Kingston, Ontario, Canada
(January, 2008)

Copyright © Chenxi Li, 2008
ABSTRACT

In this project, three separate experiments were conducted to assess heavy metal
removal from metal aqueous solutions and synthetic landfill leachate by adsorption using
low-cost natural adsorbents.
Fundamental batch investigations indicated that the 4.0-4.75 mm crushed mollusk
shells and the Sphagnum peat moss were the best adsorbents for cadmium and nickel
removal, respectively. Peat moss was also found to have the highest adsorption capacities
for manganese and cobalt adsorption.
The adsorption capacities of the peat moss and crushed mollusk shells used as natural
adsorbents for the adsorption of cadmium and nickel from binary aqueous solutions in
fixed-bed columns under continuous flow conditions were investigated. The life
expectancy of each adsorbent in the fixed-bed columns was also assessed for different
hydraulic loading rates. The flow rate of 1.5 mL/min (surface loading of 27.52
cm3/cm2·day) and bed depth of 15 cm were identified as the better operational conditions
from the column testing. The results indicated that 47.9% and 42.7% cadmium and nickel
removal efficiencies could obtained under these operational conditions, respectively.
Finally, the peat moss and the crushed mollusk shells were packed in bench-scale
down-flow fixed-bed columns to evaluate their adsorption capacities as natural low-cost
adsorbents for the removal of heavy metals from aerated and non-aerated synthetic
landfill leachate. The flow rate applied in this operation was 1.5 mL/min (surface loading
of 27.52 cm3/cm2·day). Peat was found to have the best adsorption capacities in columns
treating aerated synthetic leachate for cadmium (78.6%) and nickel (83.8%) removal
efficiencies.
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ACKNOWLEDGEMENTS

I would like to thank my supervisor, Dr. Pascale Champagne for her guidance and
financial support throughout my project.

My work could not have been conducted without the assistance of several key staff
members. As such, I would like to thank Dr. Allison Rutter and Mary Andrews in the
Analytical Services Unit at Queen’s University, and Stan Prunster in Department of Civil
Engineering for all of their help over the years.

So many thanks to my parents and my boyfriend, Calvin, for their financial supports and
love. Also, thanks to everyone who encouraged me, helped me, and gave me passion and
encouragement when I was down and lost.

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TABLE OF CONTENTS

ABSTRACT...................................................................................................................................................ⅱ
ACKNOWLEDGEMENTS........................................................................................................................iii
TABLE OF CONTENTS.............................................................................................................................iv
LIST OF FIGURES...................................................................................................................................viii
LIST OF TABLES......................................................................................................................................xii
SYMBOLS AND NOMENCLATURE…………………………………………………………………..xiv
CHAPTER 1 INTRODUCTION..................................................................................................................1
1.1 OVERVIEW........................................................................................................................................1
1.2 RESEARCH OBJECTIVES...................................................................................................................3
1.3 THESIS ORGANIZATION....................................................................................................................4
1.4 REFERENCE......................................................................................................................................8
CHAPTER 2 LITERATURE REVIEW....................................................................................................11
2.1 OVERVIEW......................................................................................................................................11
2.2 LANDFILL LEACHATE.....................................................................................................................11
2.2.1 Landfills................................................................................................................................11
2.2.2 Leachate Generation............................................................................................................12
2.2.3 Pollutants in Landfill Leachates..........................................................................................13
2.3 TREATMENT OF LANDFILL LEACHATE..........................................................................................16
2.3.1 Biological Processes.............................................................................................................17
2.3.2 Physical and Chemical Processes........................................................................................19
2.4 HEAVY METAL REMOVAL BY ADSORPTION FROM LANDFILL LEACHATE....................................21
2.4.1 Fundamentals of Adsorption Processes...............................................................................22
2.4.2 Adsorbents for Heavy Metal Removal..................................................................................23
2.4.2.1 Peat...................................................................................................................................25
2.4.2.2 Chitin and Shells.............................................................................................................31
2.4.3 Numerical Analysis of Batch and Column Studies..............................................................33
2.4.3.1 Isotherm Development and Batch Studies....................................................................33
2.4.3.2 Small-scale Fixed-bed Column Study............................................................................39
2.4.3.3 Column Test for Heavy Metal Removal from Landfill Leachate................................44
2.5 SUMMARY.......................................................................................................................................44
2.6 REFERENCE....................................................................................................................................46
CHAPTER 3 REMOVAL OF CADMIUM, NICKEL, MANGANESE AND COBALT IONS FROM
AQUEOUS SOLUTIONS USING LOW-COST NATURAL ADSORBENTS.......................................55
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3.1 INTRODUCTION............................................................................................................................55
3.2 MATERIALS AND METHODS.........................................................................................................57
3.2.1 Materials..................................................................................................................................58
3.2.1.1 Adsorbents......................................................................................................................58
3.2.1.2 Metal Solutions...............................................................................................................59
3.2.2 Methods....................................................................................................................................60
3.2.2.1 Adsorbent Characterization..........................................................................................60
3.2.2.2 Adsorption and Selection of Crushed Mollusk Shells.................................................62
3.2.2.3 Single-Constituent Metal Ion Adsorption Kinetics.....................................................64
3.2.2.4 Single-Constituent Metal Ion Equilibrium Adsorption - Individual Adsorbents.....65
3.2.2.5 Single-Constituent Metal Ion Adsorption – Adsorbent Mixtures..............................66
3.2.3 Data Analysis...........................................................................................................................67
3.2.3.1 Metal Adsorption Capacities.........................................................................................67
3.2.3.2 Isotherm Models.............................................................................................................68
3.3 RESULT AND DISCUSSION.............................................................................................................69
3.3.1 Adsorbent Characterization.....................................................................................................69
3.3.2 The Effect of Particle Size on Crushed Mollusk Shell Adsorption........................................70
3.3.3 Single-Constituents Metal Ion Adsorption Kinetics...............................................................72
3.3.3.1 Effect of Contact Time...................................................................................................72
3.3.3.2 Adsorption Capacity......................................................................................................77
3.3.3.3 Effect of pH Changes in Solution..................................................................................79
3.3.4 Single Metal Adsorption Equilibrium Isotherm Models........................................................80
3.3.4.1 Effect of initial metal ion concentration.......................................................................80
3.3.4.2 Effect of adsorbent mass................................................................................................84
3.3.4.3 Freundlich and Langmiur Models................................................................................90
3.3.5 Adsorbent mixtures..................................................................................................................96
3.4 CONCLUSION..............................................................................................................................104
3.5 REFERENCES..............................................................................................................................107
CHAPTER 4 COMPARATIVE FIXED-BED COLUMN STUDY ON THE ADSORPTION OF
CADMIUM (II) AND NICKEL (II) IONS IN BINARY METAL AQUEOUS SOLUTIONS USING
PEAT AND CRUSHED MOLLUSK SHELLS.......................................................................................111
4.1 INTRODUCTION..........................................................................................................................111
4.2 MATERIALS AND METHODS.......................................................................................................113
4.2.1 Materials................................................................................................................................113
4.2.2 Methods..................................................................................................................................116
4.2.2.1 Multi-Constituent Adsorption Study..........................................................................116
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4.2.2.2 Fixed-bed Column Set-up............................................................................................116
4.2.2.3 Sample Collection and Analysis..................................................................................119
4.2.3 Data Analysis.........................................................................................................................120
4.3 RESULTS AND DISCUSSIONS.......................................................................................................125
4.3.1 Competitive Adsorption on the Adsorbents...........................................................................125
4.3.2 Column Adsorption Capacity , Treatment Efficiency, and Exhaustion...............................128
4.3.3 Effect of Hydraulic Loading..................................................................................................133
4.3.3.1 Adsorption Using Crushed Mollusk Shells................................................................134
4.3.3.2 Adsorption Using Peat.................................................................................................137
4.3.4 Effect of bed height................................................................................................................141
4.3.4.1 Adsorption Using Crushed Mollusk Shells................................................................141
4.3.4.2 Adsorption Using Peat.................................................................................................143
4.3.5 Effect of Adsorbents on Effluent pH.....................................................................................145
4.4 CONCLUSION..............................................................................................................................146
4.5 REFERENCES..............................................................................................................................150
CHAPTER 5 BIOSORPTION OF CADMIUM (II) AND NICKEL (II) FROM SYNTHETIC
LANDFILL LEACHATE BY SPHAGNUM PEAT MOSS AND CRUSHED MOLLUSK SHELLS IN
FIXED-BED COLUMNS..........................................................................................................................153
5.1 INTRODUCTION.............................................................................................................................153
5.2 MATERIAL AND METHOD.............................................................................................................156
5.2.1 Materials.............................................................................................................................156
5.2.2 Method................................................................................................................................158
5.2.2.1 Column System.............................................................................................................158
5.2.2.2 Aeration Tank...............................................................................................................161
5.2.2.3 Bacteria and biofilm Culture in Columns...................................................................162
5.2.3 Sample Analysis..................................................................................................................162
5.2.4 Data Analysis......................................................................................................................163
5.3 RESULT AND DISCUSSION.............................................................................................................165
5.3.1 pH........................................................................................................................................165
5.3.1.1 pH in Columns Receiving Non-Aerated Synthetic Landfill Leachate......................165
5.3.1.2 pH in Columns Receiving Aerated Synthetic Landfill Leachate..............................167
5.3.2 COD Removal.....................................................................................................................169
5.3.2.1 COD Removal in Columns Receiving Non-Aerated Synthetic Landfill Leachate..170
5.3.2.2 COD Removal in Columns Receiving Aerated Synthetic Landfill Leachate...........171
5.3.3 Total Nitrogen Removal......................................................................................................172
5.3.3.1 Total Nitrogen Removal in Columns Receiving Non-Aerated Synthetic Landfill
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Leachate.......................................................................................................................................173
5.3.3.2 Total Nitrogen Removal in Columns Receiving Aerated Synthetic Landfill Leachate
174
5.3.4 Heavy Metal Removal.........................................................................................................175
5.3.4.1 Heavy Metal Removal in Column Systems Receiving Non-Aerated Synthetic
Landfill Leachate........................................................................................................................179
5.3.4.2 Heavy Metal Removal in Column Systems Receiving Aerated Synthetic Landfill
Leachate.......................................................................................................................................180
5.3.5 Clogging..............................................................................................................................183
5.4 CONCLUSION................................................................................................................................184
5.5 REFERENCE..................................................................................................................................186
CHAPTER 6 CONCLUSIONS AND RECOMMENDATIONS............................................................191
6.1 CONCLUSIONS............................................................................................................................191
6.2 RECOMMENDATIONS..................................................................................................................196
APPENDIX I: DATA AND CALCULATIONS OF CHAPTER 3.........................................................199
APPENDIX II: DATA AND CALCULATIONS FOR CHAPTER 4.....................................................279
APPENDIX III: DATA AND CALCULATIONS FOR CHAPTER 5...................................................296
APPENDIX IV: DIGITAL PICTURES...................................................................................................312

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LIST OF FIGURES

Figure 2.1 Typical landfill structure..........................................................................................................12
Figure 2.2 Typical adsorption uptake changes versus time.....................................................................34
Figure 2.3 Adsorption column mass transfer zone and idealized breakthrough zone (versus volume
treated)................................................................................................................................................40
Figure 2.4 Typical breakthrough curve in fixed –bed column.................................................................41
Figure 3.1 Effect of crushed mollusk shell particle size fractions on metal adsorption from
single-constituent metal ion solution. (І represents the AAS analytical error).............................71
Figure 3.2 Cadmium ion adsorption onto 0.6-1.0 mm shells (SA), 4.0-4.75 mm shells (SB), granular
activated carbon (GAC) and sphagnum-peat moss (PEAT) as a function of time.......................73
Figure 3.3 Nickel ion adsorption onto 0.6-1.0 mm shells (SA), 4.0-4.75 mm shells (SB), granular
activated carbon (GAC) and sphagnum-peat moss (PEAT) as a function of time.......................74
Figure 3.4 Manganese ion adsorption onto 0.6-1.0 mm shells (SA), 4.0-4.75 mm shells (SB), granular
activated carbon (GAC) and sphagnum-peat moss (PEAT) as a function of time.......................75
Figure 3.5 Cobalt ion adsorption onto 0.6-1.0 mm shells (SA), 4.0-4.75 mm shells (SB), granular
activated carbon (GAC) and sphagnum-peat moss (PEAT) as a function of time.......................76
Figure 3.6 Effect of initial cadmium ion concentration on adsorption...................................................81
Figure 3.7 Effect of initial nickel ion concentration on adsorption.........................................................82
Figure 3.8 Effect of initial manganese ion concentration on adsorption................................................82
Figure 3.9 Effect of initial cobalt ion concentration on adsorption.........................................................83
Figure 3.10 Effect of adsorbent mass on cadmium ion adsorption.........................................................84
Figure 3.11 Cadmium removal efficiencies using different adsorbent masses. (І represents the AAS
analytical error).................................................................................................................................85
Figure 3.12 Effect of adsorbent mass on nickel ion adsorption...............................................................86
Figure 3.13 Nickel removal efficiencies using different adsorbent masses. (І represents the AAS
analytical error).................................................................................................................................86
Figure 3.14 Effect of adsorbent mass on manganese ion adsorption......................................................87
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Figure 3.15 Manganese removal efficiencies using different adsorbent masses. (І represents the AAS
analytical error).................................................................................................................................88
Figure 3.16 Effect of adsorbent mass on cobalt ion adsorption...............................................................89
Figure 3.17 Cobalt removal efficiencies using different adsorbent masses. (І represents the AAS
analytical error).................................................................................................................................89
Figure 3.18 Equilibrium adsorption capacities of different adsorbent mixtures for cadmium ion
adsorption. (a) SA mixed with other media at different mass ratios, (b) SB mixed with other
media at different mass ratios, (c) GAC mixed with other media at different mass ratios, and (d)
PEAT mixed with other media at different mass ratios. (І represents the AAS analytical error).
.............................................................................................................................................................98
Figure 3.19 Equilibrium adsorption capacities of different adsorbent mixtures for nickel ion
adsorption. (a) SA mixed with other media at different mass ratios, (b) SB mixed with other
media at different mass ratios, (c) GAC mixed with other media at different mass ratios, and (d)
PEAT mixed with other media at different mass ratios. (І represents the AAS analytical error).
...........................................................................................................................................................100
Figure 3.20 Equilibrium adsorption capacities of different adsorbent mixtures for manganese ion
adsorption. (a) SA mixed with other media at different mass ratios, (b) SB mixed with other
media at different mass ratios, (c) GAC mixed with other media at different mass ratios, and (d)
PEAT mixed with other media at different mass ratios. (І represents the AAS analytical error).
...........................................................................................................................................................102
Figure 3.21 Equilibrium adsorption capacities of different adsorbent mixtures for cobalt ion
adsorption. (a) SA mixed with other media at different mass ratios, (b) SB mixed with other
media at different mass ratios, (c) GAC mixed with other media at different mass ratios, and (d)
PEAT mixed with other media at different mass ratios. (І represents the AAS analytical error).
...........................................................................................................................................................104
Figure 4.1 Schematic of the column system setup...................................................................................118
Figure 4.2 Individual column details.......................................................................................................119
Figure 4.3 Typical metal breakthrough curve observed in the column system....................................121
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Figure 4.4 Cadmium and nickel adsorption by 4.0-4.75 mm crushed mollusk shells and peat moss
from single and binary solutions in batch experiments, for adsorbent mass of 6 g and initial Cd
and Ni concentrations of 209 mg/L (1.86 mol/L)and 105 mg/L (1.79 mol/L), respectively. (І
represents the AAS analytical error)..............................................................................................126
Figure 4.5 Breakthrough curves for cadmium ion adsorption onto crushed mollusk shells in (a) 10 cm
and (b) 15 cm bed depths at loading rates of 3.4 mL/min and 1.5 mL/min................................135
Figure 4.6 Breakthrough curves for nickel ion adsorption onto crushed mollusk shells in (a) 10 cm
and (b) 15 cm bed depths at loading rates of 3.4 mL/min and 1.5 mL/min................................137
Figure 4.7 Breakthrough curves for cadmium ion adsorption onto peat in (a) 10 cm and (b) 15 cm
bed depths at loading rates of 3.4 mL/min and 1.5 mL/min.........................................................138
Figure 4.8 Breakthrough curves for nickel ion adsorption onto peat in (a) 10 cm and (b) 15 cm bed
depths at loading rates of 3.4 mL/min and 1.5 mL/min................................................................140
Figure 4.9 Breakthrough curves for (a) cadmium ion adsorption onto crushed mollusk shells for 10
cm and 15 cm column depths and (b) nickel ion adsorption onto crushed mollusk shells for 10
cm and 15 cm column depths at a hydraulic loading of 1.5mL/min............................................142
Figure 4.10 Breakthrough curves for (a) cadmium ion adsorption onto peat for 10 cm and 15 cm
column depths and (b) nickel ion adsorption onto peat for 10 cm and 15 cm column depths at a
hydraulic loading of 1.5mL/min.....................................................................................................144
Figure 5.1 Experimental Column System Schematic.............................................................................160
Figure 5.3 Effluent pH from fixed-bed columns receiving non-aerated synthetic leachate................167
Figure 5.4 Effluent pH from fixed-bed columns receiving aerated synthetic leachate........................168
Figure 5.5 COD breakthrough curves for aerated and non-aerated column systems. C is the average
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COD concentrations of the raw synthetic landfill leachate (8660 mg/L, SD=334 mg/L)...........171
Figure 5.6 Total nitrogen breakthrough curves for aerated and non-aerated column systems. C is the
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average theoretical total nitrogen concentration in the raw leachate (764.80 mg/L).................173
Figure 5.7 Experimental cadmium concentration as a function of throughput volume in aerated and
non-aerated column systems. C is the average cadmium concentration of the raw synthetic
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leachate (36.2 mg/L, SD=1.17 mg/L)..............................................................................................177
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