Catalytically Facilitated Sequestration and Transformation of Catalytically Facilitated Sequestration and Transformation of Persistent Organic Pollutants in Soils and SedimentsPersistent Organic Pollutants in Soils and Sediments
Energy and Environment Program Energy and Environment Program Department of Chemical EngineeringDepartment of Chemical EngineeringThe University of Michigan, Ann ArborThe University of Michigan, Ann Arbor
Walter J. Weber, Jr.Walter J. Weber, Jr.
March 25, 2004
Technology Benchmarking Workshop for Sediment and Floodplain Remediation
Ann Arbor, Michigan
Natural Organic Matter TransformationNatural Organic Matter Transformation
Biopolymers
Humic Acids
Fulvic Acids
Small Labile Molecules
Fulvic Acids
Humic Acids
Kerogens
Mineralization
Polymer Decomposition
Contaminant Degradation
Increasing Molecular Size
Contaminant ImmobilizationDetoxification
Humification
Catalyzed Oxidative CouplingCatalyzed Oxidative Coupling
•• Oxidative coupling Oxidative coupling •• SubstratesSubstrates
•• Phenols, anilinesPhenols, anilines•• NOM building blocksNOM building blocks
•• Mediated by a variety of naturally occurring catalystsMediated by a variety of naturally occurring catalysts•• Peroxidases, laccases, tyrosinases (plants, bacteria, fungi)Peroxidases, laccases, tyrosinases (plants, bacteria, fungi)•• Certain crystalline forms of manganese and iron oxides and hydroCertain crystalline forms of manganese and iron oxides and hydroxidesxides
•• Mechanisms Mechanisms •• EnzymeEnzyme--mediated oxidation followed by couplingmediated oxidation followed by coupling
•• Leads to polymerization Leads to polymerization
•• Applications being researchedApplications being researched•• Water treatment Water treatment •• Soil and sediment decontaminationSoil and sediment decontamination
O OHOH
PeroxidasesPeroxidases
HRPHRP--Mediated Catalytic CycleMediated Catalytic Cycle
1
23
.AH
E0 Ei
Eii
H2O2
AH2
AH2
H2O
+ H2O.AH
( Huang Q., Selig H., Weber ( Huang Q., Selig H., Weber W.J.JrW.J.Jr., ES&T, 36, 19, 2002)., ES&T, 36, 19, 2002)
Phenol Conversion via HRPPhenol Conversion via HRP--Mediated CouplingMediated Coupling
[NEP] = 234.8 [E]0
R2 = 0.994
0
50
100
150
200
250
300
0 0.2 0.4 0.6 0.8 1 1.2
HRP Dosages (unit/mL)
NE
P ( µ
M)
Formation of Non-extractable Products in HRP-mediated Aqueous Systems(Initial phenol concentration = 0.5 mM , H2O2 concentration = 2 mM)
( Huang Q. and Weber ( Huang Q. and Weber W.J.JrW.J.Jr., ES&T, in review) ., ES&T, in review)
Catalytically Facilitated Sequestration and Transformation (Catalytically Facilitated Sequestration and Transformation (CFaSTCFaST) ) of of POPsPOPs in Phenolin Phenol--Based Oxidative Coupling SystemsBased Oxidative Coupling Systems
•• Phenanthrene transformation in semiPhenanthrene transformation in semi--batch reactorsbatch reactors
0
20
40
60
80
100
120
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5
Time (days)
Phen
anth
rene
con
cent
ratio
n ( µ
g/L
)
0
1000
2000
3000
4000
5000
6000
Phen
ol C
onve
rsio
n ( µ
M)
Extracted phenanthrene
Dissolved phenanthrene
Phenol conversion
Phenanthrene Disappearance in Solution and in 50% Methanol Extractions and Phenol Conversion
(0.25mM phenol, 0.25mM H2O2, and 1unit/mL HRP were added repeatedly five times a day)
( Weber ( Weber W.J.JrW.J.Jr. and Huang Q., ES&T, 37,18, 2003). and Huang Q., ES&T, 37,18, 2003)
CFaSTCFaST of of POPsPOPs in Phenolin Phenol--Based Oxidative Coupling SystemsBased Oxidative Coupling Systems
•• Phenanthrene transformation in Phenanthrene transformation in CFaSTCFaST systems of different reaction strengthsystems of different reaction strength
Phenanthrene Disappearance in Solution under Varying Reaction ConditionsThe ratio of inputs (Phenol: H2O2:HRP) are maintained constant for different CFaST systems
( Weber ( Weber W.J.JrW.J.Jr. and Huang Q., ES&T 37,18, 2003). and Huang Q., ES&T 37,18, 2003)
0
20
40
60
80
100
120
0 1 2 3 4 5Time (days)
Dis
solv
ed p
hena
nthr
ene
( µg/
L)
Dilution effect0 mM Phenol0.005 mM Phenol0.025 mM Phenol0.125 mM Phenol0.25 mM Phenol
CFaSTCFaST of of POPsPOPs in Phenolin Phenol--Based Oxidative Coupling SystemsBased Oxidative Coupling Systems
•• Phenanthrene removed and extractability in sorption and Phenanthrene removed and extractability in sorption and CFaSTCFaST systemssystems
•• Points of notePoints of note•• Greater sorption in the Greater sorption in the CFaSTCFaST systemsystem•• Lower extractability in the Lower extractability in the CFaSTCFaST system system
0102030405060708090
100
0 200 400 600 800 1000 1200 1400 1600 1800 2000
Precipitated Coupling Products (mg/L)
% P
hena
nthr
ene
Extracted phenanthrene in sorption system
Dissolved phenanthrene in sorption system
Dissolved phenthrene in CFaST system
Extracted phenanthrene in CFaST system
CFaSTCFaST of of POPsPOPs in Phenolin Phenol--Based Oxidative Coupling SystemsBased Oxidative Coupling Systems
•• Analysis of precipitated productsAnalysis of precipitated products
Radioactivity HPLC(µg/g) 102.1 88.87 69.23 5.74Std 1 1.59 1.29 0.13
CFaST % 100 87.04 67.81 5.62% std 0.98 1.56 1.26 0.12(µg/g) 19.64 18.5 18.74 6.93E-04
Sorption std 0.55 0.38 0.69 5.20E-03% 100 94.21 95.44 0
% std 2.78 1.93 3.49 0.03
Remained radioactivity after MSESystem
Phenanthrene Concentration
Total radioactivity before MSE
MSE Extracts
•• Points of notePoints of note•• Chemical binding occurs; phenanthrene apparently activated by Chemical binding occurs; phenanthrene apparently activated by
radical transfer mechanismsradical transfer mechanisms•• Physical sequestration still plays an important role, but is enhPhysical sequestration still plays an important role, but is enhancedanced
CFaSTCFaST of of POPsPOPs in Phenolin Phenol--Based Oxidative Coupling SystemsBased Oxidative Coupling Systems
•• Processes in simple sorption systemsProcesses in simple sorption systems
Sorbent Sorption Diffusion Aging
Phenanthrene Polymer formation Polymer growth Polymer reformation
•• Processes in Processes in CFaSTCFaST systemssystems
•• Points of notePoints of note•• CFaSTCFaST process is mechanistically different than physical sequestratioprocess is mechanistically different than physical sequestration n •• Higher capacity, lower Higher capacity, lower leachabilityleachability, loss of chemical identity, dynamic , loss of chemical identity, dynamic
processes having potential for further transformation processes having potential for further transformation
Sorbent Effects on Sorbent Effects on CFaSTCFaST with Phenol as a Surrogate “POP”with Phenol as a Surrogate “POP”
Biopolymers
Humic Acids
Fulvic Acids
Small Labile Molecules
Fulvic Acids
Humic Acids
Kerogens
Mineralization
Polymer Decomposition
Contaminant Degradation
Increasing Molecular Size
Contaminant Immobilization/Detoxification
Humification
0
100
200
300
400
500
0 50 100 150 200 250
Solid/water ratio (g/L)
NE
P ( µ
M)
PMScellulosesillica sand
A
0
100
200
300
400
500
0 50 100 150 200 250
Solid/water ratio (g/L)
NE
P ( µ
M)
PMScellulosesillica sand
A
0
100
200
300
400
500
0.00 0.20 0.40 0.60 0.80 1.00 1.20
Solid/water ratio (g/L)
NE
P ( µ
M)
lignin B
0
100
200
300
400
500
0.00 0.20 0.40 0.60 0.80 1.00 1.20
Solid/water ratio (g/L)
NE
P ( µ
M)
lignin B
Sorbent Effects on Sorbent Effects on CFaSTCFaST with Phenol as a Surrogate “POP”with Phenol as a Surrogate “POP”
Formation of non-extractable products (NEP) in systems containing different solids initial phenol concentration = 0.5 mM, H2O2 concentration = 2 mM, HRP = 0.5 unit/mL
( Huang Q. and Weber ( Huang Q. and Weber W.J.JrW.J.Jr., ES&T, in review) ., ES&T, in review)
Sorbent Effects on Sorbent Effects on CFaSTCFaST with Phenol as a Surrogate “POP”with Phenol as a Surrogate “POP”
0
0.3
0.6
0.9
1.2
1.5
1.8
0 10 20 30 40 50
Solid/water ratio (g/L)
HR
P in
activ
atio
n ra
te c
onst
ant
(mL
/uni
t-m
in)
cellulosesilica sandPMS
0
0.3
0.6
0.9
1.2
1.5
1.8
0 10 20 30 40 50
Solid/water ratio (g/L)
HR
P in
activ
atio
n ra
te c
onst
ant
(mL
/uni
t-m
in)
cellulosesilica sandPMS
0
0.3
0.6
0.9
1.2
1.5
1.8
0 0.2 0.4 0.6 0.8 1
Solid/water ratio (g/L)H
RP
inac
tivat
ion
rate
con
stan
t(m
L/u
nit-
min
)
lignin
0
0.3
0.6
0.9
1.2
1.5
1.8
0 0.2 0.4 0.6 0.8 1
Solid/water ratio (g/L)H
RP
inac
tivat
ion
rate
con
stan
t(m
L/u
nit-
min
)
lignin
HRP inactivation rate constants in systems containing different solids
initial phenol concentration =500 µM, H2O2 concentration = 2 mM, HRP = 0.5 unit/mL
( Huang Q. and Weber ( Huang Q. and Weber W.J.JrW.J.Jr., ES&T, in review ) ., ES&T, in review )
Sorbent Effects on Sorbent Effects on CFaSTCFaST with Phenol as a Surrogate “POP”with Phenol as a Surrogate “POP”
0
20
40
60
80
100
0 50 100 150 200 250
Solid/water ratio (g/L)
Disso
lved
enz
yme
(%)
Native HRP
Compound-I
Compound-II
A
0
20
40
60
80
100
0 50 100 150 200 250
Solid/water ratio (g/L)
Dis
solv
ed E
nzym
e (%
)
B
0
20
40
60
80
100
0 50 100 150 200 250
Solid/water ratio (g/L)
Dis
solv
ed e
nzym
e (%
)
C
0
20
40
60
80
100
0 2 4 6 8 10 12
Solid/water ratio (g/L)
Dis
solv
ed e
nzym
e (%
)
D
( Huang Q. and Weber ( Huang Q. and Weber W.J.JrW.J.Jr., ES&T, in review) ., ES&T, in review)
•• HRP sorption on different solidsHRP sorption on different solids
Sorbent Effects on Sorbent Effects on CFaSTCFaST with Phenol as a Surrogate “POP”with Phenol as a Surrogate “POP”
100
200
300
400
500
600
700
0.6 0.8 1.0 1.2
(k in') -1 (unit-min/mL)
CTN
(nm
ole/
unit)
Cellulose Silica Sand
Lignin PMS
( Huang Q. and Weber ( Huang Q. and Weber W.J.JrW.J.Jr., ES&T, in review) ., ES&T, in review)
Relationship between turnover capacity (CTN) and HRP inactivation rate constants (kin’)
Conclusions Regarding Conclusions Regarding CFaSTCFaST of of POPsPOPs in Phenolin Phenol--Based Oxidative Coupling SystemsBased Oxidative Coupling Systems
•• Chemical transformation and irreversible sequestrationChemical transformation and irreversible sequestration•• Activation of Activation of POPsPOPs through radical transfer processesthrough radical transfer processes
•• Hydrogen abstractionHydrogen abstraction•• Free radical additionFree radical addition
•• Incorporation in products through covalent bondingIncorporation in products through covalent bonding•• Permanently immobilizedPermanently immobilized•• Loose chemical identity Loose chemical identity •• Detoxified Detoxified
•• Enhanced physical sequestrationEnhanced physical sequestration•• Concomitant sorption and sorbent formation processesConcomitant sorption and sorbent formation processes
•• Sorbate distribution profilesSorbate distribution profiles•• Desorption energies Desorption energies
Conclusions RegardingConclusions RegardingSorbent Effects on Sorbent Effects on CFaSTCFaST with Phenol as a Surrogate “POP”with Phenol as a Surrogate “POP”
•• Mitigation of enzyme inactivationMitigation of enzyme inactivation•• Enzyme sorptionEnzyme sorption•• Relatively hydrophilic and oxygenRelatively hydrophilic and oxygen--containing solidscontaining solids
•• CrossCross--couplingcoupling•• Aromatic featuresAromatic features•• SubstituentsSubstituents•• Lignin > Chelsea soil > Lachine shale > PMS > CelluloseLignin > Chelsea soil > Lachine shale > PMS > Cellulose
•• Lignin > Lachine Shale > PMSLignin > Lachine Shale > PMS•• Lignin > Chelsea Soil > CelluloseLignin > Chelsea Soil > Cellulose
Conclusions RegardingConclusions RegardingSorbent Effects on Sorbent Effects on CFaSTCFaST with Phenol as a Surrogate “POP”with Phenol as a Surrogate “POP”
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
2.2
2.4
0 0.2 0.4 0.6 0.8 1 1.2
H/C
O/C
Chelsea Soil
Cellulose
LigninLachine ShalePMS
Conclusions Regarding Conclusions Regarding Technology Development NeedsTechnology Development Needs
•• Creating optimal NOM conditionsCreating optimal NOM conditions•• Engineered geosorbents amendmentsEngineered geosorbents amendments
•• SubSub--critical water treatment of geosorbents critical water treatment of geosorbents
•• Facilitating chemical sequestration and transformations Facilitating chemical sequestration and transformations of specific of specific POPsPOPs•• PCBs, PCBs, PCDDsPCDDs, , PCDFsPCDFs•• Different catalysts Different catalysts •• Enzyme consortiaEnzyme consortia
•• Hydroxylation + Coupling Hydroxylation + Coupling