Princeton University “Princeton

Goals

Research

Shale Gas Impacts

Emissions & Climate

Geochemistry

News

Publications

Presentations


Jeffrey P. Fitts
Research Scientist

Department of Civil and Environmental Engineering
Princeton University
EQuad E-208
Princeton NJ 08544

Tel: (609) 258-5158
email: fitts@princeton.edu


Curriculum Vitae

 

Research Goals

My research combines experimental and material structure probes with numberical methods to study chemical reactions at interfaces that drive the evolution of environmental systems. The aim is to advance the Geochemical Science and Engineering needed to develop increasingly robust quantitative projections of the human health, environmental and climatic costs of energy technologies. We frequently use synchrotron-based x-ray probes to study dissolution-driven evolution of 3D structures and contaminant speciation at mineral-water interfaces within porous and fractured materials.  Current projects aim to assess contaminant mobility and fugitive methane emissions during shale gas extraction, permeability evolution of leakage pathways through caprocks of perspective geologic CO2 storage reservoirs, stability of encapsulated nuclear waste, and activity of catalysts for wastewater treatment.

Research topics and projects

Forecasting Shale Gas Wastewater Treatment Demand

Environmental impact assessments submitted with shale gas well permit applications would ideally include forecasts of contamination levels in flowback and produced wastewaters (FPW). A mechanistic understanding of contaminant mobilization from shale is needed to predict FPW composition a priori based on fracking fluid chemistry, shale formation mineralogy and contaminant speciation within the shale. We are developing complementary approaches that directly probe mobilization mechanisms by coupling fractured core and packed bed column flow experiments with synchrotron-based x ray imaging methods. The approach is used to derive contaminant mobilization rates by combining effluent chemistry with an accurate measure of accessible reactive surface area before and after reactive flow using x ray tomography 3D imaging of the evacuated columns with Xenon gas as a contrast agent. The mobilization rates are then attributed to specific release mechanisms such as iron sulfide oxidation, calcite dissolution or desorption from clays by characterizing contaminant mineral association, coordination chemistry and spatial distribution within the shale using x ray microspectroscopy. This experimental approach is intended to inform the predictive geochemical models needed to design and optimize FPW treatment.

Quantifying Fugitive Methane Emissions Over a Shale Gas Well's Life Cycle

Production of natural gas from shale formations is an expanding industry, but hydraulic fracturing, aka hydrofracking, produces vast quantities of flowback and production wastewaters, hereafter FPW. A resulting environmental concern is the mobilization of metals and radionuclides from the shale formation. Industrial treatment operations use precipitation and flocculation to remove hazardous elements from FPW, but these processes are kinetically limited and inhibited by the numerous substances present in the chemically-complex wastewater. This investigation seeks to study the mobilization of the hazardous elements barium (Ba), uranium (U) and radium (Ra) from fractured shale formation rocks using high-pressure reactive flow experiments under a range of geochemical conditions created in hydrofracking operations. To gain insights about the governing geochemical processes, synchrotron-based microspectroscopy will be employed to map these hazardous elements according to their associations with mineral and organic phases.

Assessing Caprock Integrity Overlying Prospective Geological CO2 Reservoir Formations

Caprocks are impermeable sedimentary formations that overlie prospective geologic CO2 storage reservoirs. As such, caprocks will be relied upon to trap CO2 and prevent vertical fluid migration and leakage. Natural and industrial analogues provide evidence of long-term performance of caprocks in holding buoyant fluids. However, the large volumes of CO2 that must be injected and stored to meaningfully reduce anthropogenic greenhouse gas emissions will exert unprecedented geomechanical and geochemical burdens on caprock formations due to elevated formation pressures and brine acidification. This chapter reviews experimental observations and model developments that have advanced our ability to predict how the geochemical burdens of CO2 storage might alter leakage rates through caprocks. Our review is motivated by the question: Under what conditions and to what extent might mineral dissolution increase leakage rates through caprocks? This question anchors the focus of this paper on practical assessment tools, highlighting simplifying assumptions and the tradeoffs between assessment complexity and uncertainty. Thus far, assessments indicate that leakage risks will be manageably low at properly sited geologic CO2 storage reservoirs. Economic and commercial viability of GCS, concerns over environmental protection, as well as social dimensions of public acceptance will likely demand reductions in uncertainty about caprock performance that can only be addressed by improving the parameterization and computational efficiency of predictive models. A significant portion of this research has been funded by two grants from the US DOE's Office of Fossil Energy: a collaboration led by Penn State University on Mineralogical and geomechanical controls on on fracture failure in induced seismic events, and a completed project on Basin-Scale Leakage Risk of Geologic CO2 Storage..

Fundamental Studies of Physico-chemical Processes at Mineral/Water Interfaces

Predictions of mass transfer across fracture boundaries and fluid flow in fracture networks provide fundamental inputs into risk and life cycle assessments of geologic energy technologies including oil and gas extraction, geothermal energy systems and geologic CO2 storage. However, major knowledge gaps exist due to the lack of experimental observations of how reactive fluids alter the pore structures and accessible surface area within fracture boundaries that control the mass transfer of organics, metals and salts, and influence fluid flow within the fracture. To investigate the fracture and rock matrix properties governing fracture boundary alteration, we developed a new flow-through cell that enables time-dependent 2D x-ray imaging of mineral dissolution and/or precipitation at a fracture surface. The parallel plate design provides an idealized fracture geometry to investigate the relationship between flow rate, reaction rate, and mineral spatial heterogeneity and variation. In the flow-cell, a carbonate-rich sample of Eagle Ford shale was reacted with acidified brine. The extent and rate of mineral dissolution were correlated with calcite abundance relative to less soluble silicate minerals. Three-dimensional x-ray tomography of the reacted fracture wall shows how calcite dissolution left behind a porous network of silicate minerals. And while this silicate network essentially preserved the location of the initial fracture wall, the pore network structures within the fracture boundary were dramatically altered, such that the accessible surface area of matrix components increased significantly. In a second set of experiments with a limestone specimen, however, the extent of dissolution and retreat of the fracture wall was not strictly correlated with the occurrence of calcite. Instead, the pattern and extent of dissolution suggested secondary causes such as calcite morphology, the presence of argillaceous minerals and other diagenetic features. Our experiments show that while calcite dissolution is the primary geochemical driver of fracture wall alterations, hydrodynamic properties and matrix accessibility within fracture boundaries evolve based on a complex relationship between mineral spatial heterogeneity and variation, fluid chemistry and flow rate.

News & Events

August 17-20, 2015 - Upcoming presentation at ACS Fall Meeting in Boston.

"Contaminant mobilization from shale during hydrofracking and gas production"

June 14, 2015 - Upcoming presentation at AEESP conference at Yale University.

"Forecasting contaminant mobilization from shale into gas production wastewaters"

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May 31-June 5, 2015 - Participating in Gordon Research Conference on Carbon Emissions Mitigation Technologies (CCUS) GRC conference at Stonehill College.

Keynote speakers - Rob Socolow and Jeff Sachs

May 6, 2015 - Congratulations to Dr. Hang Deng for defending her thesis!!! 1. Deng, H. GEOCHEMICAL ALTERATIONS OF FRACTURES AND THE ENVIRONMENTAL AND POLICY IMPLICATIONS. Princeton University, Princeton, 2015. .

Peer-Reviewed Publications & Book Chapters

Morandeau, A.; Fitts, J. P.; Lee, H. D.; Shubeita, S.; Feldman, L.; Gustafsson, T.; White, C. E., Nanoscale Heterogeneities in a Fractured Alkali-Activated Slag Binder: A Helium Ion Microscopy Analysis. Cement and Concrete Research 2015, In press. (request preprint)

Deng, H.; Fitts, J. P.; Crandall, D.; McIntyre, D.; Peter, C. A., Alterations of fractures in carbonate rocks by CO2-acidified brines. Environmental Science & Technology 2015, ASAP Web version. (preprint pdf)

Zhuang, W.-Q.; Fitts, J. P.; Ajo-Franklin, C. M.; Maes, S.; Alvarez-Cohen, L.; Hennebel, T., Recovery of critical metals using biometallurgy. Current Opinion in Biotechnology 2015, 33, 327-335. (pdf)

Leijonhufvud, C.; Fitts, J. P., Global Warming’s Unlikely Antidote: Why capital markets hold the key to addressing climate change. Social Research 2015, In press. (request preprint)

Bielicki, J. M.; Peters, C. A.; Fitts, J. P.; Wilson, E. J., An Examination of Geologic Carbon Sequestration Policies in the Context of Leakage Potential. International Journal of Greenhouse Gas Control 2015 37:61–75.

Deng, H.; Bielicki, J.M.; Oppenheimer, M.; Fitts, J. P.; Peters, C. A., A Methodology for Monetizing Basin-Scale Leakage Risk and Stakeholder Impacts. Energy Procedia 2014, 63:6852-6863.

Pierce, E. M.; Lukens, W. W.; Fitts, J. P.; Jantzen, C. M.; Tang, G., Experimental determination of the speciation, partitioning, and release of perrhenate as a chemical surrogate for pertechnetate from a sodalite-bearing multiphase ceramic waste form. Applied Geochemistry 2014, 42, (0), 47-59.

Bielicki, J. M.; Pollak, M. F.; Fitts, J. P.; Peters, C. A.; Wilson, E. J., Causes and Financial Consequences of Geologic CO2 Storage Reservoir Leakage and Interference with other Subsurface Resources. International Journal of Greenhouse Gas Control 2014, 20, 272-284.

Fitts, J. P.; Peters, C. A., Caprock Fracture Dissolution and CO2 Leakage. In Geochemistry of Geologic CO2 Sequestration, Depaolo, D. J.; Cole, D. R.; Navrotsky, A.; Bourg, I. C., Eds. Mineralogical Society of America: 2013, 77, 459-479.

Dahl, T. W.; Chappaz, A.; Fitts, J. P.; Lyons, T. W., Molybdenum reduction in a sulfidic lake: Evidence from X-ray absorption fine-structure spectroscopy and implications for the Mo paleoproxy. Geochim. Cosmochim. Acta 2013, 103, (0), 213-231.

Deng, H.; Ellis, B. R.; Peters, C. A.; Fitts, J. P.; Crandall, D.; Bromhal, G. S., Modifications of carbonate fracture hydrodynamic properties by CO2-acidified brine flow. Energy & Fuels 2013, 27, (8), 4221–4231.

Ellis, B. R.; Fitts, J. P.; Bromhal, G. S.; McIntyre, D. L.; Tappero, R.; Peters, C. A., Dissolution-Driven Permeability Reduction of a CO2 Leakage Pathway in a Carbonate Caprock. Environmental Engineering Science, 2013, 30, (4), 187-193.

Johnson, A.; Merilis, G.; Hastings, J.; Palmer, M. E.; Fitts, J. P.; Chidambaram, D., Reductive Degradation of Organic Compounds Using Microbial Nanotechnology. Journal of the Electrochemical Society 2013, 160, (1), G27-G31.

Bielicki, J. M.; Pollak, M. F.; Wilson, E. J.; Fitts, J. P.; Peters, C. A., A Methodology for Monetizing Basin-Scale Leakage Risk and Stakeholder Impacts. Energy Procedia 2013, 37, 4665-4672.

Hennebel, T.; Fitts, J. P.; Van Nevel, S.; Boon, N., Pd nanocatalysts for PCB removal. In Nanotechnology for Water and Wastewater Treatment, Lens, P.; Virkutyte, J.; Jegatheesan, V.; Kim, S.-H.; Al-Abed, S., Eds. IWA Publishing: London, UK, 2013; p 350.

Pollak, M. F.; Bielicki, J. M.; Dammel, J. A.; Wilson, E. J.; Fitts, J. P.; Peters, C. A., The Leakage Impact Valuation (LIV) Method for Leakage from Geologic CO2 Storage Reservoirs. Energy Procedia 2013, 37, 2819-2827.

Nogues, J. P.; Fitts, J. P.; Celia, M. A.; Peters, C. A., Permeability evolution due to dissolution and precipitation of carbonates using reactive transport modeling in pore networks. Water Resources Research 2013, 49, 1-16.

Kumpiene, J.; Fitts, J. P.; Mench, M., Arsenic Fractionation in Contaminated Mining Spoils 10 Years after Amendment. Environmental Pollution 2012, 166, 82-88.

Fitts, J. P. & Thieme, J., Looking into the nanoworld using X-rays. Edited special issue of Chemical Geology 2012, 329, 1-2.

Landrot, G.; Ginder-Vogel, M.; Livi, K.; Fitts, J. P.; Sparks, D. L., Chromium(III) Oxidation by Three Poorly-Crystalline Manganese(IV) Oxides. 1. Chromium(III)-Oxidizing Capacity. Environ. Sci. Tech. 2012, 46, (21), 11594-11600.

Landrot, G.; Ginder-Vogel, M.; Livi, K.; Fitts, J. P.; Sparks, D. L., Chromium(III) Oxidation by Three Poorly Crystalline Manganese(IV) Oxides. 2. Solid Phase Analyses. Environ. Sci. Tech. 2012, 46, (21), 11601-11609.

Ellis, B.R., Peters, C.A., Fitts, J.P., Bromhal, G.S., McIntyre, D.L., Warzinski, R.P., Rosenbaum, E.J., Deterioration of a fractured carbonate caprock exposed to CO2-acidified brine flow.  Greenhouse Gases: Sci. and Tech. 2011, 1 (3) 248-260.

Elzinga, E.J., Gao, Y., Fitts, J.P., and Tappero, R., Iron speciation in urban dust.  Atmospheric Environment 2011, 45 (26), pp 4528-4532.

Kumpiene, J., Mench, M., Bes, C. M., and Fitts, J.P., Assessment of aided phytostabilization of copper-contaminated soil by X-ray absorption spectroscopy and chemical extractions.  Environmental Pollution 2011, 159 (6), pp 1536-1542.

De Corte, S., Hennebel, T., Fitts, J.P., Sabbe, T., Bliznuk, V., Verschuere, S., van der Lelie, D., Verstraete, W., Boon, N., Bio-supported bimetallic Pd-Au nanocatalysts for dechlorination of environmental contaminants.  Environ. Sci. & Tech. 2011 45 (19), 8506–8513.

Hennebel, T., van Nevel, S., Verschuere, S., De Corte, S., De Gusseme, B., Cuvelier, C., Fitts, J.P., van der Lelie, D., Boon, N., Verstraete, W., Palladium nanoparticles produced by fermentatively cultivated bacteria as catalyst for diatrizoate removal with biogenic hydrogen. Applied Microbio. and Biotech. 2011, 91 (5), 1435-1445.

Johnson, A., Merilis, G., Hastings, J., Palmer, M. E., Fitts, J. P., and Chidambaram, D., ‘Nanotechnology and Microbial Electrochemistry for Environmental Remediation’, Electrochemical Society Transactions 2011, 33 (38), 103-112.

De Gusseme, B., Hennebel, T., Christiaens, E., Saveyn, H., Verbeken, K., Fitts, J.P., Boon, N., Verstraete, W., Virus Disinfection in Water by Biogenic Silver Immobilized in Polyvinylidene Fluoride Membranes.  Water Research 2011, 45 (4), pp 1856-1864.

De Gusseme, B., Du Laing, G., Hennebel, T., Renard, P., Chidambaram, D., Fitts, J. P., Bruneel, E., van Driessche, I., Verbeken, K., Boon, N., Verstraete, W., Biogenic cerium exhibits virucidal properties. Environ. Sci. & Tech. 2010, 44 (16) pp 6350–6356.

Chidambaram, D.; Hennebel, T.; Taghavi, S.; Mast, J.; Boon, N.; Verstraete, W.; van der Lelie, D.; Fitts, J. P., Concomitant Microbial Generation of Palladium Nanoparticles and Hydrogen To Immobilize Chromate. Environ. Sci. Tech. 2010, 44, (19), 7635-7640.

Moreels, D.; Crosson, G.; Garafola, C.; Monteleone, D.; Taghavi, S.; Fitts, J. P.; van der Lelie, D., Microbial community dynamics in uranium contaminated subsurface sediments under biostimulated conditions with high nitrate and nickel pressure. Environ. Sci. Pollut. Res. 2008, 15 (6), 481-491.

Fthenakis, V. M.; Fuhrmann, M.; Heiser, J.; Lanzirotti, A.; Fitts, J.; Wang, W., Emissions and encapsulation of cadmium in CdTePV modules during fires. Prog. Photovoltaics 2005, 13 (8), 713-723.

Fitts, J. P.; Shang, X. M.; Flynn, G. W.; Heinz, T. F.; Eisenthal, K. B., Electrostatic surface charge at aqueous/alpha-Al2O3 single-crystal interfaces as probed by optical second-harmonic generation. J. Phys. Chem. B 2005, 109 (16), 7981-7986.

Fitts, J. P.; Machesky, M. L.; Wesolowski, D. J.; Shang, X. M.; Kubicki, J. D.; Flynn, G. W.; Heinz, T. F.; Eisenthal, K. B., Second-harmonic generation and theoretical studies of protonation at the water/a-TiO2 (110) interface. Chem. Phys. Lett. 2005, 411 (4-6), 399-403.

Fuhrmann, M.; Fitts, J. P., Adsorption of trace metals on glass fiber filters. J. Environ. Qual. 2004, 33 (5), 1943-1944.

Rim, K. T.; Muller, T.; Fitts, J. P.; Adib, K.; Camillone, N.; Osgood, R. M.; Batista, E. R.; Friesner, R. A.; Joyce, S. A.; Flynn, G. W., Scanning tunneling microscopy and theoretical study of competitive reactions in the dissociative chemisorption of CCl4 on iron oxide surfaces. J. Phys. Chem. B 2004, 108 (43), 16753-16760.

Bargar, J. R.; Trainor, T. P.; Fitts, J. P.; Chambers, S. A.; Brown, G. E., In situ grazing-incidence extended X-ray absorption fine structure study of Pb(II) chemisorption on hematite (0001) and (1-102) surfaces. Langmuir 2004, 20 (5), 1667-1673.

Rim, K. T.; Fitts, J. P.; Muller, T.; Adib, K.; Camillone, N.; Osgood, R. M.; Joyce, S. A.; Flynn, G. W., CCl4 chemistry on the reduced selvedge of a alpha-Fe2O3(0001) surface: a scanning tunneling microscopy study. Surf. Sci. 2003, 541 (1-3), 59-75.

Adib, K.; Totir, G. G.; Fitts, J. P.; Rim, K. T.; Mueller, T.; Flynn, G. W.; Joyce, S. A.; Osgood, R. M., Chemistry of CCl4 on Fe3O4(111)-(2 x 2) surfaces in the presence of adsorbed D2O studied by temperature programmed desorption. Surf. Sci. 2003, 537 (1-3), 191-204.

Adib, K.; Mullins, D. R.; Totir, G.; Camillone, N.; Fitts, J. P.; Rim, K. T.; Flynn, G. W.; Osgood, R. M., Dissociative adsorption of CCl4 on the Fe3O4(111)-(2 x 2) selvedge of alpha-Fe2O3(0001). Surf. Sci. 2003, 524 (1-3), 113-128.

Camillone, N.; Adib, K.; Fitts, J. P.; Rim, K. T.; Flynn, G. W.; Joyce, S. A.; Osgood, R. M., Surface termination dependence of the reactivity of single crystal hematite with CCl4. Surf. Sci. 2002, 511 (1-3), 267-282.

Adib, K.; Camillone, N.; Fitts, J. P.; Rim, K. T.; Flynn, G. W.; Joyce, S. A.; Osgood, R. M., CCl4 chemistry on the magnetite selvedge of single-crystal hematite: competitive surface reactions. Surf. Sci. 2002, 497 (1-3), 127-138.

Trainor, T. P.; Fitts, J. P.; Templeton, A. S.; Grolimund, D.; Brown, G. E., Grazing-incidence XAFS study of aqueous Zn(II) sorption on alpha- Al2O3 single crystals. J. Colloid Interface Sci. 2001, 244 (2), 239-244.

Fitts, J. P.; Brown, G. E.; Parks, G. A., Structural evolution of Cr(III) polymeric species at the gamma-Al2O3/water interface. Environ. Sci. & Tech. 2000, 34 (24), 5122-5128.

Trainor, T. P.; Fitts, J. P.; Grolimund, D.; Bargar, J. R.; Brown, G. E., Grazing-incidence XAFS studies of aqueous Zn(II) on sapphire single crystals. J. Synchrot. Radiat. 1999, 6, 618-620.

Grolimund, D.; Trainor, T. P.; Fitts, J. P.; Kendelewicz, T.; Liu, P.; Chambers, S. A.; Brown, G. E., Identification of Cr species at the aqueous solution-hematite interface after Cr(VI)-Cr(III) reduction using GI-XAFS and Cr L-edge NEXAFS. J. Synchrot. Radiat. 1999, 6, 612-614.

Fitts, J. P.; Trainor, T. P.; Grolimund, D.; Bargar, J. R.; Parks, G. A.; Brown, G. E., Grazing-incidence XAFS investigations of Cu(II) sorption products at alpha-Al2O3-water and alpha-SiO2-water interfaces. J. Synchrot. Radiat. 1999, 6, 627-629.

Fitts, J. P.; Persson, P.; Brown, G. E.; Parks, G. A., Structure and bonding of Cu(II)-glutamate complexes at the gamma- Al2O3-water interface. J. Coll. & Inter. Sci. 1999, 220 (1), 133-147.

Friedman, I. I.; Bischoff, J. L.; Johnson, C. A.; Tyler, S. W.; Fitts, J. P., Movement and diffusion of pore fluids in Owens Lake sediments from core OL-92 as shown by salinity and deuterium-hydrogen ratios. Geological Society of America Special Papers 1997, 317, 49-66. (pdf)

Bischoff, J. L.; Fitts, J. P.; Fitzpatrick, J. A., Responses of sediment geochemistry to climate change in Owens Lake sediment: An 800-k.y. record of saline/fresh cycles in core OL-92. Geological Society of America Special Papers 1997, 317, 37-47. (pdf)

Bischoff, J. L.; Menking, K. M.; Fitts, J. P.; Fitzpatrick, J. A., Climatic oscillations 10,000-155,000 yr B.P. at Owens Lake, California reflected in glacial rock flour abundance and lake salinity in core OL-92. Quat. Res. 1997, 48 (3), 313-325. (pdf)

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Select Presentations

Forecasting contaminant mobilization from shale into gas production wastewaters” 2015 AEESP Research and Education Conference, Yale University, June 15, 2015 (co-authors Heather Hunter, Kasparas Spokas, Catherine A. Peters).

How reactive fluids alter fracture walls and affect shale-matrix accessibility” Abstract H14D-06 oral presentation at 2014 AGU Fall Meeting, San Francisco, CA December 15, 2014 (co-authors H. Deng, C.A. Peters).

Geophysical and Mineralogical Controls on the Rheology of Fracture Slip and Seal Breaching” co-presented with Derek Elsworth (Penn State U.) at FOA 1037 Kickoff Meeting, NETL Pittsburg, PA November 12, 2014.

Pore-Scale Representation and Modeling” discussion leader at Flow & Transport in Permeable Media Gordon Research Conference, Bates College, Lewiston, ME July 11, 2014.

Current State of CO2 Utilization” presented as invited panelist on Global Large-Scale Projects on CCUS and their Outlook at Columbia University’s RCN CCUS Annual Meeting and Workshop, New York, NY April 14, 2014.

 “Mineralogical controls on contaminant levels in wastewater from shale gas operations” Photon Sciences Directorate Seminar Series, Brookhaven National Lab’s National Synchrotron Light Source II, Upton, NY March 28, 2014.

 “Geochemical Proxies in shale for gas production, contaminant mobility and ocean oxygenation” Department of Earth & Environmental Sciences Seminar Series, Rutgers University, Newark, NJ March 12, 2014.

 “The Geochemical and Spatial Frontiers of Gas-bearing Shale” Presented at NSLS II First-Experiments workshop, Upton, NY August 12, 2013.

“Spatial Variation of Dissolution at Fracture Boundaries” Goldschmidt Florence, Mineralogical Magazine, 77(5) 1092. DOI:10.1180/minmag.2013.077.5.6, August 2013.

"Creating a Window into the Subsurface: The Potential for In Situ Imaging of Fluid-rock Interactions at SRX" Rock & Cell Workshop on Early Science for NSLS II, Upton, NY, September 19, 2012.

"Basin-Scale Leakage Risks from Geologic Carbon Sequestration: Impact on CCS Energy Market Competitiveness” NETL Carbon Storage Program Annual Meeting, Pittsburg, PA, August 23, 2012.

"Geochemical controls on fracture evolution in carbon sequestration" American Rock Mechanics Association Annual Meeting (ARMA), Chicago, IL, June 25, 2012.

"Putting Interfacial Chemistry to Work for Civil & Environmental Engineering" Princeton University, Civil & Environmental Engineering Department, Princeton, NJ, April 19, 2011.

"Statistical Challenges Facing Pore-Scale X-ray Imaging Results" presented at the workshop on “Supercritical CO2-Material Interactions” BNL, Upton, NY, March 23, 2011.

"Evaluating Geologic CO2 Storage: How will geochemistry impact reservoir performance?" Stony Brook University Department of Geosciences Colloquium & Graduate Seminar, October 28, 2010.

“Unlocking the many faces of nanoparticle structure” presented to The Laboratory of Microbial Ecology and Technology (LabMET), Faculty of Bioscience Engineering at Ghent University, Belgium, September 14, 2010.

“Supporting remediation strategy design and implementation with synchrotron-based x-ray characterization tools” presented at Northern Sweden Soil Remediation Center Spring Workshop, Lövånger, Sweden May 11, 2010.

 “Basin-Scale Leakage Risks from Geologic Carbon Sequestration: Impact on CCS Energy Market Competitiveness” presented at DOE/EPA Collaborative Review – Tracking Geologically-Sequestered CO2: Monitoring, Verification, & Accounting (MVA), Simulation, and Risk Assessment, Pittsburg, PA March 23, 2010.

Applying biogeochemical concepts to ensure that today's solutions don't become tomorrow's problems: Geologic CO2 storage” School of Earth and Environmental Sciences Colloquium, Queens College November 23, 2009.

Synchrotron X-ray Microprobe: A Tool for Nuclear Forensics Jeffrey Fitts, Michael Rosenthal, Barry Siskind, P. Northrup, meeting of U.S. NWAL laboratories, Washington, DC October 29, 2008.

One Environmental Science User’s Perspective on Scanning Transmission X-ray Microscopy” Canadian Light Source Earth & Environmental Science Workshop, Saskatoon, Saskatchewan, Canada May 5, 2008.

Center for Geologic Carbon Storage Science (CGCSS)” Presentation to EENS visiting committee during review of the Environmental Sciences Department, July 23, 2008.

 “Advancing experimentally-based models of mineral-water interfaces” Invited presentation at Geological Society of America Annual Meeting special session in honor of Prof. Gordon E. Brown Jr. Oct. 2007.

EXAFS and SHG studies of mineral-water interfaces: applications and limitations” Presented at ‘Surface Reactions & Electrical Interfacial Layer: Experiments and Models - Towards a Common Basis’ sponsored by European Union ACTINET Opatija, Croatia October 9, 2007.

Synchrotron-based investigations of biogeochemical transformations of priority contaminants in soils at DOE sties” Nuclear Summer School at BNL presented July 17, 2007.

 “Biotransformations of engineered nanoparticles in the environment” Presented at CEMS Fall meeting Stony Brook University November 2, 2006.

Synchrotron-based investigations of biogeochemical transformations of priority contaminants in soils at DOE sites” Nuclear Summer School at BNL presented July 18, 2006.

"Composition Of Microbial Communities Used For In Situ Radionuclide Immobilization: Natural Gene Transfer To Develop Resistance To Metal Toxicity" invited oral presentation at the ERSP PI meeting in Warrenton, VA April 3, 2006.

 “Zeroing in on structure-reactivity relationships at aqueous/metal oxide mineral interfaces” Oak Ridge National Lab Chemical Sciences Division presented October 24, 2005.

"Charging behavior at water/single crystal oxide interfaces determined by optical second harmonic generation spectroscopy" invited oral presentation in the symposium "Applications of Physical Chemistry to Environmental and Biogeochemical Research" at the 229th ACS National Meeting in San Diego, CA, March 13-17, 2005.

 “Illuminating Mineral-Water Interfaces” Geosciences Department Colloquium at Stony Brook University presented December 9, 2004.

EnviroSuite: Using State-Of-The-Art Synchrotron Techniques to Understand Environmental Remediation Science Issues at the Molecular Level” Waste Management 2004 Conference Proceeding published online at www.wastemanagement.com, Tucson, AZ, 2004.

"Real-world contaminant behavior explored through studies of model systems" CEMS annual meeting, presented at Stony Brook University on May 14, 2004.