Extension of COSMO-RS to interfacial phenomena Martin P. Andersson et al. Nano-Science Center Department of Chemistry University of Copenhagen Denmark Presentation at the 4th COSMO-RS symposium Mar 2015 Page 1
Environment and Energy The NanoGeoScience Research Section ma@nano.ku.dk stipp@nano.ku.dk
Apply nanotechnology Discover nature s secrets Find solutions to society s challenges ensuring cleaner water storing waste more safely converting CO 2 from gas to mineral producing more oil from existing reservoirs learning mysteries of biomineralisation Photo: Siggi Gislason, Iceland
Approaches Experimental Field studies sample collection Classical methods X-ray diffraction, etc. Wet-chemical methods (spectrometry, potentiometry, etc.) Nano-techniques Atomic Force Microscopy Surface Spectroscopy Electron Microscopy X-ray Scattering and Other Synchrotron Radiation Techniques Theoretical Molecular Modelling Density Functional Theory Molecular Dynamics
Approaches Experimental Field studies sample collection Classical methods X-ray diffraction, etc. Wet-chemical methods (spectrometry, potentiometry, etc.) Nano-techniques Atomic Force Microscopy Surface Spectroscopy Electron Microscopy X-ray Scattering and Other Synchrotron Radiation Techniques Theoretical Molecular Modelling Density Functional Theory Molecular Dynamics
Who are we? Interdisciplinary 2 biologists 20 chemists 7 engineers 11 geologists/mineralogists 2 mathematicians 9 nano-science 9 physicists Gender balanced ~10 associated senior scientists from KU, other countries and industry International half Danish half from: Australia Canada China Costa Rica Croatia France Germany Indonesia Iran Italy Japan Nepal Norway Russia Spain Sweden Switzerland Turkey USA July 2014
Why is the interface important? Same kind of fundamental interactions between surfaces determine how clean drinking water in an aquifer can be how to get more oil out of a reservoir how injected CO 2 travels through a rock. Biomineralization - how organisms grow minerals Page 7
anogeoscience Energy and nvironm ent Oil reservoir NanoGeoScience Water Oil Water Rock Oil Rock Page 8
Energy and Environm ent CO 2 sequestration NanoGeoScience Water CO 2 Water Rock CO 2 Rock Page 9
Which surface properties matter? Surface chemistry Surface charge Page 10
Outline Liquid/liquid interfaces pk a of acids and bases at interfaces IFT model MAMBAKSS Water Oil Gas/liquid interfaces CO 2 /water - Poster by Alessandro Silvestri Water CO 2 Solid/liquid interfaces Adsorption Poster by Akin Budi pk a for surface groups and water at the surface IFT model Water Rock Page 11
Liquid/Liquid interfaces Water Oil Page 12
Partial solvation with flatsurf Allows molecules to be placed at an interface between two liquid phases. Perform calculations for both protonated and deprotonated forms of acids and bases at an oil/water interface DG Change in pk a compared to bulk water. Page 13
acids and bases at an oil/water interface Page 14
pk a for acids and bases at an oil/water interface Page 15
Enrichment of acids and bases at an oil/water interface Page 16
Acid and base properties at an oil/water interface influence Surface chemistry Surface charge Page 17
Partial solvation with flatsurf Allows molecules to be placed at an interface between two liquid phases. Calculate the free energy for the molecule at the interface as well as the area of crossection. DG Energy / area -> IFT (mj/m 2 = mn/m) Page 18
Create a surface phase make a surface phase of proper composition Based on flatsurf energies oil surface water Page 19
IFT for binary water/organic systems ~10 4 times faster than MD predictions Page 20
Ternary water/organic systems Page 21
IFT (mn/m) NanoGeoScience Ternary organic/organic systems 10 9 8 7 Propylenecarbonate/Decane/X 6 5 4 3 2 1 0 Page 22 X = dodecene (exp.) X = dodecene (calc.) X = dodecanal (exp.) X = dodecanal (calc.) 0 0,1 0,2 0,3 mole fraction of compound X
IFT module is available in the latest version of COSMOtherm Page 23
Gas/Liquid interfaces Water CO 2 Page 24
IFT of the CO 2 /water interface Poster by Alessandro Silvestri Page 25
Solid/Liquid Water Rock interfaces Oil Rock Page 26
pk a of water at a calcite interface Page 27
pk a of water at a calcite interface Page 28
pk a of water at a solid interface Equilibrium structure for each surface site Understanding and modeling surface charge Important for modeling crystal growth and dissolution Page 29
pk a of surface groups at a solid surface Surface pk a has also been predicted for CO 3 groups at calcite Silica nanoparticles Kaolinite clay Page 30
Periodic solvation Allows COSMO-RS solvation to be used with periodic boundary conditions Molecules adsorbed on solids from a liquid. DMol3 / PBE Page 31
Adsorption energy on a solid in various solvents NanoGeoScience Vacuum Page 32 Different solvent
Adsorption on a solid For molecules in liquids and at liquid/liquid interfaces, the degrees of freedom are very similar A molecule adsorbed on a solid has very different degrees of freedom compared to being free in a liquid Calculate the molecular partition functions for vibration, rotation and translation Poster by Akin Budi.
The IFT model extension to solids Liquid/liquid Solid/liquid oil DG flatsurf liquid surface surface water solid
The IFT model extension to solids Liquid/liquid Solid/liquid oil DG flatsurf liquid surface surface water solid
Why do we need solid/liquid interfacial tension? Use computational techniques to predict surface wettability. cosq = (g ws g os ) / g ow Page 36
Why do we need solid/liquid interfacial tension? Use computational techniques to predict surface wettability. cosq = (g ws g os ) / g ow g ws = g ws,cosmo-rs + g s g os = g os,cosmo-rs + g s Page 37
Examples of solid-liquid interfacial tension Water-hexane(s): 65 mn/m Water-C 2 F 4 (s): Hexane-C 2 F 4 (s): 66 mn/m 15 mn/m Water-calcite(s): -12 mn/m
Self assembled monolayers (SAM) X is a mixture of -CH 3 and -OH -NH 2 -COOH X X X X X Smooth, flat surface with tunable chemistry and wettability. S S S S S Au
Contact angles for mixed CH 3 /COOH self assembled monolayers Contact angle 180 150 120 90 60 30 0 Calc. Exp. 0 0,5 1 % acid in SAM
Acid pairs on the surface of a COOH self-assembled monolayer None, one or two internal hydrogen bonds possible Different stability in water and hydrocarbon
Conclusions COSMO-RS can be very well suited for prediction of interfacial properties: Protonation Surface Charge Interfacial tension Adsorption Page 42
Acknowledgements Funding BP p.l.c. Maersk Oil Research & Technology Center Members of the NanoGeoScience group at the University of Copenhagen The COSMOlogic team Page 43
Questions? Publications Oil/water interface pk a Langmuir 2014, 30, 6437 6445 Liquid/liquid Interfacial tension Journal of Chemical Theory and Computation 2014, 10, 3401 3408 pk a of water adsorbed on calcite Journal of Physical Chemistry C 2012, 116, 18779 18787 Page 44
Some details of the Liquid/Liquid IFT method First, the partitioning between the two bulk phases is calculated Assume a starting IFT Estimate the mole fractions of the surface phase Calculate the DG (G tot ) and the area (A av ) for all components DG Page 45
Some details of the Liquid/Liquid IFT method NanoGeoScience Page 46
Some details of the Liquid/Liquid IFT method Total number of COSMO-RS calculations: ~10-100 Total computational time depends strongly on the number of components and their size. For a three component system with water, hexadecane and the surfactant SDS <1 minute The calculation provides: IFT between the bulk phases Composition of the surface phase Page 47