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The Use of Natural Dispersants and their Implications for Deepwater Horizon Oil
Spill Remediation
Dr. Dawn Fox, Dr. Maria T. Celis, Dr. Ryan Toomey, Dr. Daniela Stebbins, and
Dr. Norma A. Alcantar [email protected]
Nanosurface-Chemistry and Green Materials Chemistry Laboratory
C-MEDS: Consortium for the Molecular Engineering of Dispersants Systems
Lead Institution: Tulane University
Gulf Research Initiative (GoMRI)
Cactus Mucilage The Opuntia ficus-indica cactus (a.k.a. Nopal or prickly pear) produces a gum-like substance: MUCILAGE
Nopal mucilage is an important constituent of the cactus: a thick, gum-like substance precipitates ions, heavy metals,
bacteria, and particles has special surface active
characteristics provides the cactus’ ability to store
large amounts of water
Nopal mucilage is an important constituent of the cactus: a thick, gum-like substance precipitates ions, heavy metals,
bacteria, and particles has special surface active
characteristics provides the cactus’ ability to store
large amounts of water
T = 0 min T = 10 min
20 nm
Nopal mucilage is an important constituent of the cactus: a thick, gum-like substance precipitates ions, heavy metals,
bacteria, and particles has special surface active
characteristics provides the cactus’ ability to store
large amounts of water
Nopal mucilage is an important constituent of the cactus: a thick, gum-like substance precipitates ions, heavy metals,
bacteria, and particles has special surface active
characteristics provides the cactus’ ability to store
large amounts of water
Mucilage Extracts
COMBINED GE + NE
Macerated Pads
GE Gelling extract
fraction of raw mucilage
NE Non-gelling extract
fraction of raw mucilage
Effect of mucilage on surface oil
The mucilage is able to disperse oil
Surface tension vs. concentration of cactus mucilage, NE ( %W/V)
Our initial approach is to study the surface active properties of mucilage/oil dispersions
Research Approach Static analysis Dispersion particle size and distribution Stability Effect of salt in the dispersion
Droplet size of Oil/water/NE mucilage [30:70:%W/V]
10001500200025003000350040004500500055006000
0 0.5 1 1.5
Num
ber a
vera
ge d
iam
eter
(nm
)
Cactus mucilage concentration (w/v. % )
GE
NE
Combined
Dynamic analysis Shear rate effects Structural changes of the dispersant under various
shear rates Effect of salt and mucilage (dispersant) concentration
2700
2900
3100
3300
3500
3700
3900
0 3 6 9 12 15
Num
ber
aver
age
diam
eter
(nm
)
Salt concentration (w/v .%)
Variation of droplet size Mineral oil / water / mucilage
Function of salt concentration [0.5 mucilage w/v.%]
NE
GE
Combined
Surface Forces Apparatus
Scalability, cost, and life cycle assessment
Acknowledgements
Gulf Research Initiative C-MEDS Tulane University Vijay John, Keith Johnston, Arijit Bose, Kalliat Valsaraj, All members and staff of C-MEDS
National Science Foundation CBET: 1057897 under Dr. Robert Wellek’s division
Phase-Selective Organogels (PSOs): Eco-Friendly Oil Spill Clean-Up Materials from Sugars
Objective: The goal of this proposal is to underpin the design principles to develop molecular gelators from biomass, that are biodegradable, efficiently gels crude oil and crude oil fractions, facilitate removal of oil gel from water surface and subsequent recovery of oil. Specifically:
1) to systematically study the influence of (a) the stereochemistry of sugars, and (b) the hydrophobicity of the fatty acid part of the ‘gelator’ (amphiphile).
1) to study the microstructure, viscoelasticity and thermoreversibility behavior of the gel.
Gulf of Mexico Research Initiative
George John, Depar tment of Chemistr y The City College of the City University of New York, E-mail: [email protected]
FRG - 3
Design and Synthesis
The concept is: i) to design amphiphilic
molecules that preferentially partition into the organic phase as well as exhibit a balance between dissolution into and crystallize out of the organic solvent.
ii) to develop a method for the gelation at ambient temperature thereby rendering it more energy efficient and practical towards oil spill clean-up technologies.
Scheme 1: Enzymatic Synthesis of Amphiphiles
FRG - 3
Gulf of Mexico Research Initiative
Preliminary Data and Plan
• To better elucidate the gelation mechanism of the PSO in crude oil, we plan to characterize the crude oil gels by various physico-chemical techniques like microscopy (optical and SEM), scattering (X-ray diffraction) and rheology.
FRG - 3
Gulf of Mexico Research Initiative
Scheme 1: Phase-Selective Gelation of Oils
Implication of Work
The overall implication of work with crude oil is that: • The PSOs have not only exhibited the potential to be
used for cleaning up of refined oils such as diesel, but have exhibited the potential for crude oil spill remediation.
• The starting materials being biomass and abundant in
nature render the PSO derivatives to be biodegradable, environmentally friendly and relatively inexpensive to produce for large scale applications.
Gulf of Mexico Research Initiative
FRG - 3
[email protected] http://www.che.lsu.edu/faculty/hung
Adsorption of hydrocarbons and dispersants on atmospheric air/salt water interfaces
Francisco R. Hung Cain Department of Chemical Engineering, Louisiana State University,
Baton Rouge, LA, USA
2
Rationale • Large fraction of oil from 2010 DWH
accident accumulated on sea surface
• Volatile organic compounds (VOCs) evaporate; but intermediate (IVOC) and semi-volatiles (SVOC) remain on sea surface
• Bubble-bursting, white caps will carry IVOCs, SVOCs, dispersants into atmosphere; preliminary results (Valsaraj) suggests these mechanisms are important
• Neglected in previous studies Figure courtesy of K. T. Valsaraj
• Classical molecular dynamics (MD) simulations of adsorption of organics at salt water/air interfaces, when surfactants/dispersants are absent/present
• In collaboration with K. T. Valsaraj (experiments) • Fundamental understanding of interfacial properties → determine which/how much
organics were transported into atmosphere, contribute to aerosolization
3
Proposed work • MD simulations of adsorption of organics at salt water/air
interfaces, when surfactants/dispersants are absent/present • Alkanes of different chain lengths (C15-C39) → oil mousse
samples • Water + NaCl • Standard surfactants; also model compounds from Corexit
9500/9527
• Determine: • Potentials of mean force • Interfacial properties (density profiles, order parameters,
surface tension, radial distribution functions)
Slab with aqueous salt solution
Vacuum region (air)
y
z
x
Sodium dodecyl sulfate (SDS)
O
OHOHHO
O
O
Sorbitan monooleate
0
0.2
0.4
0.6
0.8
1
-20-10
0102030405060
10.5 11.5 12.5 13.5D
ensi
ty (a
rbitr
ary
units
)
PMF
(kJ/
mol
)
Z-axis (nm)
PMF
W
4
Preliminary results Potentials of mean force
C15
• Next: interfacial properties; larger alkanes; dispersants • Combine with experiments from Valsaraj’s group → Fundamental understanding of
interfacial properties → determine which/how much organics were transported into atmosphere, contribute to aerosolization
0
0.2
0.4
0.6
0.8
1
-40-20
020406080
100
10.5 12.5 14.5
Den
sity
(arb
itrar
y un
its)
PMF
(kJ/
mol
)
Z-axis (nm)
PMF
W
C30
Environmental Implications of Alternative Dispersants
Robert Hurt and Agnes Kane
Institute for Molecular and Nanoscale Innovation;
School of Engineering, Dept. of Pathology and Laboratory Medicine
Brown University, Providence, Rhode Island, USA
Presented at the GRI Review Meeting, San Diego, March 2012
Core competencies: environmental / health implications of emerging technologies, toxicology, nanomaterial fate, transport, and transformation in enviro/bio-systems
Visiting Prof. Rene Rangel-Mendez
Ph.D. student Megan Creighton
Engineering the hydrophilic / lipophilic balance (HLB)
Performance and Implications of Particle-Based Dispersants
The extent of functionalization influences:
The free energy driving force for assembly of Pickering emulsions
The toxicity and bioaccumulative tendency of nanoparticles surface treatment to impart hydrophilicity is observed to decrease nanotoxicity by an unknown mechanism. Membrane disruption? Protein interactions? hydrophobicity favors partitioning to fatty tissues and bioaccumulation
The adsorption of toxic aromatic petroleum fractions and bioavailability reduction aromatic adsorption is driven by hydrophobic forces; reduced by hydrophilic treatment?
Prof. Arijit Bose, URI
Stages of Larval Development Williams, Biol. Bull., 187, 164, 1994 Ingestion of carbon black nanoparticles by a metanauplius 48 hours after hatching – exposed to
10 ppm (1mg/L) for 4 hours with no toxicity.
Preliminary Data on Aromatic Adsorption and Ecotoxicity
Adsorption behavior
Model Organism: Artemia
LC50 = 10 μg/ml 30% decrease in GSH after 24 hours Ruebhart et al., J. Toxicol. Environ. Health, 72, 1567, 2009 Criddle et al., J. Biol. Chem., 281, 40485, 2006
1. Toxicity Endpoints • Reduced motility and
death • Depletion of GSH • Lipid peroxidation
2. Stress Responses • Heat shock proteins (hsc 70,hsp 21, p26) • Iron binding protein (artemin)
Ecotoxicity in Artemia: Particles, Aromatics, and Their Mixtures
FIRST FOCUS: BENZENE / PARTICLES
Cytochrome P450 metabolism
FUTURE: BIOACCUMULATION
Thermodynamic and Interfacial Behaviors in Hydrate Forming Emulsions
Jae W. Lee, Chemical Engineering, The City College of New York
Goals: 1) Determine phase equilibria of hydrate forming emulsions. 2) Examine interfacial behaviors of hydrate particles in various
environments.
µ−DSC
Figure 1. CP hydrate equilibrium temperature.
Hydrophobicized Silica Pickering Emulsion
60 to 40 vol. % of Cyclopentane to H2O 7nm Silica Particle
1.0, 2.5, 5.0, and 7.5 wt %
CP Hydrate Equilibria Determined by DSC wt% (in
CP) Hydrate Dissociation
(oC) - Average 1 6.58
2.5 6.15 5 6.00
7.5 5.53
0.0 2.5 5.0 7.5 10.00
5
10
15
Emul
sion
Aver
age
Size
(micr
on)
Future Plans 1) Determine phase equilibria of CP hydrates in silica
emulsions with electrolytes and surface-active agents. 2) Oil-water interfacial tensions In Tensiometer (low T, electrolyte) 3) Adhesion force measurements
Oil-Soluble Components Water Soluble Components
Surface-active agents
AOT, Span 65/80, C16E1 SDS, DTAB, Triton X100, PVP, PVCap
Non-soluble particles
Fe2O3 (20 – 100 nm), Janus (0.8 – 8 µm): Hydrophobic silica-Fe deposition
Hydrate former Cyclopentane, methane Tetrahydrofuran (THF), Acetone
Non-hydrate former
Decane, Light mineral oil NaCl (0 – 600 mM)
Operating T & P 273.16 K – 280 K & 1 bar – 100 bar
Water
Oil
Water
Oil
Contact&
Detach)
c)
Microstructures of poly-(ethylene) oxide chain solute in water and
n-hexane solutions
Hot Oil-Cold Seawater Interaction at Depth
Amitava Roy J. Bennett Johnston, Sr., Center for Advanced Microstructures and
Devices (CAMD), Louisiana State University, Baton Rouge, Louisiana
Objectives: Study droplet/ bubble formation, their size distribution, composition and thermodynamic properties at the microscopic scale in the presence of dispersants at pressures comparable to DWH spill.
Concept and Physical Principles
• Based on molecular weight and solubility in different
solvents, crude oil is composed of several fractions • During production and processing phase separation can
occur easily • Interaction of hot oil mixed with seawater at depth
should lead to phase separation and precipitation
Preliminary Data/Plans All components, including gas, will be considered in this study • Small and Wide Angle Scattering (X-ray, light(?),
and neutron (?)) • X-Ray Diffraction • Differential Scanning Calorimetry 1. Experiments will be conducted in experimental cells at
pressures and temperatures comparable to DWH spill. 2. CAMD’s SAXS beamline may be an ideal beamline for
this study where the flux is not too high to volatilize low boiling point components.
3. All these techniques can be combined at a synchrotron beamline (for example, the Photon Factory, at Tsukuba, Japan; DND-CAT at the Advanced Photon Source, Chicago).
Phase separation during surface degradation. Do the same processes occur when the hot oil emerges from the seabed?
Angle (2θ)10 20 30 40
Inte
nsity
(cps
)
0
25
50
75
100
Emulsified In Situ Burn
from near Venice, LA
n-napthene
X-Ray Diffractometry
Asphaltene
Implications of work • This study will produce data necessary for
modeling dispersion of hydrocarbons in the deep sea in the presence of dispersants.
UPTAKE AND DISPERSION OF CRUDE OIL FROM WATER USING (R)-N-ALKYL-12-HYDROXYOCTADECYLAMMONIUM
SALTS AND AMMONIUM DITHIOCARBAMATES OF AMINO-SUBSTITUTED POLYSILOXANES
Richard G. Weiss Department of Chemistry Georgetown University
Washington, DC 20057-1227 Email: [email protected]
Background Where we are Future research
Background
N(CH2)nH
H HOH
+Y-
HSnY
xPSil
Si
CH3
CH3
OSi
O
CH2
CH3
1-X XNH3
H3N
HN
H3N
HN
H3NS
S
S
SH3N
NH
H3N
NH3
SS
CH2
CH2
NH2xPSil-S
Mallia, Terech, Weiss J. Phys. Chem. B, 2011, 115, 12401–12414
Yu, Wakuda, Blair, Weiss, J. Phys. Chem. C 2009, 113, 11546-11553
HSN-n-Y
gasoline naphtha xylol 30 min after adding an equal wt of 10PSil-S water (bottom) and
before contact with vial samples appearance of 10PSil-S
after removal from vial samples
Where we are: Gels with xPSil-S
% Swelling (w/w) = [(Wg-Wp)/Wp] х 100%
Where we are: Dispersions with HSN-n-Y ~ 2 mg N-propyl-(R)-12-hydroxyoctadecylammonium salts (HSN-3-Y) in 20-50 mg methanol added to mixture of 100 mg gasoline and ~2.5
g water and agitated by hand
Future research With xPSil-S Measure rates of swelling Measure rates of deswelling Determine mechanism of uptake and loss Investigate different x
With HSN-n-Y Investigate different n Investigate different Y Determine nature of dispersions and changes
over time Correlate nature of dispersions and efficiency
of dispersion formation with n and Y
PERHAPS: PERFORM EXPERIMENTS WITH CRUDE OIL
Compare fresh and salt water results
Effects of Pressure on Surfactant
Micellization
Hank Ashbaugh and Bin Meng
Tulane University
Goal: Examine the effects of pressure on
dispersant micellization using molecular
simulations with an eye toward
understanding roles of surfactant, chemistry
and formulation additives on assembly.
Volume of Assembly
G RT lnCMC
V assembly RT lnCMC
PT
C8E5 in water
Lesemann et al. Langmuir (1998)
Up to 2 miles (324 bar)
Deepwater Horizon ~1 mile
Semi-Submersible
Oil Rig
Partial Molar Volumes
Sodium Decyl
Sulfate
Molar Volume of Assembly
Monomer
Micelle
Kirkwood-Buff Analysis
Head Group Domain
Tail Group Domain
surf kT 1 g r drV
Design on Nanoparticles for Stable
Emulsion Droplets at Subsea Conditions
Department of Chemical Engineering
University of Texas Austin
PI: Keith P. Johnston
Students: Zheng (Eric) Xue, Ki Youl Yoon, Andrew Worthen
Research scientist: Hitesh Bagaria
Bryant, Huh, Nguyen (Petroleum, Geosyst.) Milner (BME), Bielawski (polymer org. chemist) Polymer coatings: interfacial properties CO2 sequestration and EOR
Image reservoirs
Nanoparticles at interfaces in porous media: nanomaterials
synthesis, colloid/interface science with polymer science
q q water
CO2
CO2
water
CO2
water
DOE Frontiers of Subsurface
Energy Security (UT-Sandia)
vdWvdW
Steric
Steric
Objectives
• Design nanoparticles for stabilization of emulsions
– Surface coatings to influence contact angle
– high salinity, range of temperatures
– high pressure and presence of light gases
• Fundamental understanding of emulsion stability as a function of surface coating on nanoparticles
– Relationship to emulsion phase behavior
– Interfacial tension and nanoparticle adsorption at oil/water interface
– Oil/water phase ratio and oil composition to understand inversion
• Emulsion phase type and int. and contact angle at the brine-gas expanded liquid interface (Dickson, Binks, 2004) analogous to water-CO2 system.
• Alkane-water phase diagram of nonylphenol ethoxylate (Igepal co520) undergoes phase inversion from propane to dodecane at 200 bar (McFann and Johnston, 1993).
Influence of oil, temperature and pressure on emulsion phase
behavior and interfacial properties versus nanoparticle coating
Design sulfonate copolymer coated ion oxide nanoparticles to control interfacial properties
FeCl2 & FeCl3
+
sulfonate
Polymer
Nucleation
0
20
40
60
80
100
120
0 100 200 300
Rel
ativ
e V
olu
me
Per
cen
t[%
]
Sizes[nm]
DLS Measurement
Nanoparticlestable
at high salinities
pH6 pH8 growth
• Iron oxide superparamagnetic nanoparticles (primary nanoparticle size ~8 nm) synthesized by hydrolysis of ferrous and ferric chlorides.
• Copolymer influences interfacial properties, eg. PAA and PSS
• Design electrosteric stabilization for seawater conditions
TEM Image
3% NaCl
5% NaCl
Captive CO2 bubble for IFT measurement axisymmetric drop shape analysis: Laplace equation
Known surf. concentration in water
Iron oxide nanoclusters Stabilized with amphiphilic polymer to adsorb strongly at the oil/water interface
oil
water
PAA114-b-PBA26 PAA114-b-PBA67 PAA114-b-PBA38
No emulsion
with PAA coated
Iron Oxide
O/W emulsion with amphiphilic
copolymer coated iron oxide
50 um 50 um 50 um
PAA114-b-PBA26 PAA114-b-PBA38 PAA114-b-PBA67
•Larger hydrophobic portion increases the emulsion droplet sizes
• Amphiphilic polymer stabilizers caused the iron oxide nanoclusters to adsorb
strongly at the oil/water interface
• Long-term dispersion stability (more than 1 month)
O/W
Emulsion
Iron oxide nanoclusters Stabilized with amphiphilic polymer to adsorb strongly at the oil/water interface
Coating γ [mN/m] ΔE [kT]
Dodecane-water 52.8 N/A
PAA114-b-PBA26 25.2 -3.9.E×104
PAA114-b-PBA38 28 -3.5.E×104
PAA114-b-PBA67 30.3 -2.4.E×104
PAA 133-r-PBA44 28.2 -1.2.E×105
PAA No change :too
hydrophilic N/A
IFT of 0.27% coated NPs at oil-water
interface
• Large reductions in ift of up to 27.6 mN/m with 0.27 wt% NPs
• Nanoparticle polymer coating
governs ift reduction
• Strong adsorption energy favors droplet stability
2)0
( aE
a :The particle radius η : The 2-dimensional packing fraction 𝛾o = 52.8 mN/m (Dodecane-Water) 𝛾 : Interfacial tension
Adsorption Energy
00
Objectives
• Design nanoparticles for stabilization of emulsions
– Surface coatings to influence contact angle
– high salinity, range of temperatures
– high pressure and presence of light gases
• Fundamental understanding of emulsion stability as a function of surface coating on nanoparticles
– Relationship to emulsion phase behavior
– Interfacial tension and nanoparticle adsorption at oil/water interface
– Oil/water phase ratio and oil composition to understand inversion
Biodegradable Oil Dispersants (Chris Bielawski, Chem. Dept.)
Modify side chain to optimize
interfacial activity
(R = alkyl, aryl, protected
alcohols, etc.)
Controlled molecular weight
Current producers of polylactide: Cargill Dow LLC, Mitsui Toatsu
Optimize:
• Nanoparticle (clay, SiO2, FexOy) • Polymer structure • Particle size • Degradation ability (surfactant structure)
Biodegradable Polymer Nanoparticles:
Biodegradable Polymers:
Large Scale Synthesis: