Physiochemical Transformations
Physiochemical Transformations


Odeta Qafoku is chemist with the Biogeochemical Transformations team in PNNL’s Environmental Molecular Sciences Division and the Environmental Molecular Sciences Laboratory (EMSL) user program. Qafoku is an environmental soil scientist and geochemist with 20 years of research experience on a broad range of projects in the topics of soil science, geochemistry, geochemical and thermodynamic modeling, mineral synthesis, organic and contaminant interaction with soil minerals, CO2 sequestration, and mineral weathering. Her resent research interests are in studying organic mineral interactions using methods that extend from nano- to macroscale; studying iron mineral transformations induced by reductive reactions; studying mineral incipient weathering as function of biological inputs and environmental changes, and applying scanning electron microscopy to study reactivity and transformation at reaction boundaries.  

Research Interest

  • Surface and interfaces characterization

  • Redox reactivity studies

  • Modeling and thermodynamic calculations

  • Investigation of complex systems

  • High pressure/elevated temperature reactivity studies

  • Synthesis of pure minerals

  • Reactivity and transformation at reaction boundaries, with particular interest in investigating solid -fluid interfaces at microscopic scale 

  • Chemical processes that control and influence the behavior of nutrient and contaminants under a variety of (bio)geochemical conditions 

  • Early changes of mineral weathering at microscale, as a function of biological inputs in various humid environments 

Disciplines and Skills

  • Electron Microscopy
  • Environmental Chemistry
  • Geochemical Modeling
  • Geochemistry
  • Soil Chemistry
  • Soil Science
  • Thermodynamic Modeling


  • MS in Soil Science, University of Georgia, 1998
  • BS in Chemistry, University of Tirana, 1988

Affiliations and Professional Service

  • American Geophysical Union 

  • Soil Science Society of America 

  • Microscopy Society of America 



McElroy, E., A. R. Lawter, D. Appriou, F. Smith, M. Bowden, O. Qafoku, L. Kovarik, J. E. Szecsody, M. J. Truex, and N. P. Qafoku. 2020. “Iodate Interactions with Calcite: Implications for Natural Attenuation.” Environmental Earth Sciences 79 (12).

Placencia-Gómez, E., S. N. Kerisit, H. S. Mehta, O. Qafoku, C. J. Thompson, T. R. Graham, E. S. Ilton, and J. S. Loring. 2020. “Critical Water Coverage During Forsterite Carbonation in Thin Water Films: Activating Dissolution and Mass Transport.” Environmental Science and Technology 54 (11): 6888-6899.

Sheng, A., J. Liu, X. Li, O. Qafoku, R. N. Collins, A. M. Jones, C. I. Pearce, C. Wang, J. Ni, A. Lu, and K. M. Rosso. 2020. “Labile Fe(III) from Sorbed Fe(II) Oxidation Is the Key Intermediate in Fe(II)-Catalyzed Ferrihydrite Transformation.” Geochimica et Cosmochimica Acta 272: 105-120.

Zhao, Q., S. J. Callister, A. M. Thompson, R. K. Kukkadapu, M. M. Tfaily, L. M. Bramer, N. P. Qafoku, S. L. Bell, S. E. Hobbie, E. W. Seabloom, E. T. Borer, and K. S. Hofmockel. 2020. “Strong Mineralogic Control of Soil Organic Matter Composition in Response to Nutrient Addition across Diverse Grassland Sites.” Science of the Total Environment 736.


Huang, X., Y. Chen, E. Walter, M. Zong, Y. Wang, X. Zhang, O. Qafoku, Z. Wang, and K. M. Rosso. 2019. “Facet-Specific Photocatalytic Degradation of Organics by Heterogeneous Fenton Chemistry on Hematite Nanoparticles.” Environmental Science and Technology 53 (17): 10197-10207.

Miller, Q. R. S., D. A. Dixon, S. D. Burton, E. D. Walter, D. W. Hoyt, A. S. McNeill, J. D. Moon, K. S. Thanthiriwatte, E. S. Ilton, O. Qafoku, C. J. Thompson, H. T. Schaef, K. M. Rosso, and J. S. Loring. 2019. “Surface-Catalyzed Oxygen Exchange During Mineral Carbonation in Nanoscale Water Films.” Journal of Physical Chemistry C 123 (20): 12871-12885.

Ohno, T., N. J. Hess, and N. P. Qafoku. 2019. “Current Understanding of the Use of Alkaline Extractions of Soils to Investigate Soil Organic Matter and Environmental Processes.” Journal of Environmental Quality 48 (6): 1561-1564.

Saslow, S. A., S. N. Kerisit, T. Varga, K. C. Johnson, N. M. Avalos, A. R. Lawter, and N. P. Qafoku. 2019. “Chromate Effect on Iodate Incorporation into Calcite.” ACS Earth and Space Chemistry 3 (8): 1624-1630.


Asmussen, R. M., C. I. Pearce, B. W. Miller, A. R. Lawter, J. J. Neeway, W. W. Lukens, M. E. Bowden, M. A. Miller, E. C. Buck, R. J. Serne, and N. P. Qafoku. 2018. “Getters for Improved Technetium Containment in Cementitious Waste Forms.” Journal of Hazardous Materials 341: 238-247.

Lawter, A. R., W. L. Garcia, R. K. Kukkadapu, O. Qafoku, M. E. Bowden, S. A. Saslow, and N. P. Qafoku. 2018. “Technetium and Iodine Aqueous Species Immobilization and Transformations in the Presence of Strong Reductants and Calcite-Forming Solutions: Remedial Action Implications.” Science of the Total Environment 636: 588-595.

Lawter, A. R., N. P. Qafoku, R. M. Asmussen, R. K. Kukkadapu, O. Qafoku, D. H. Bacon, and C. F. Brown. 2018. “Element Mobilization and Immobilization from Carbonate Rocks between CO2 Storage Reservoirs and the Overlying Aquifers During a Potential CO2 Leakage.” Chemosphere 197: 399-410.

Popel, A. J., T. W. Wietsma, M. H. Engelhard, A. S. Lea, O. Qafoku, C. Grygiel, I. Monnet, E. S. Ilton, M. E. Bowden, and I. Farnan. 2018. “The Effect of Ion Irradiation on the Dissolution of UO2 and UO2-Based Simulant Fuel.” Journal of Alloys and Compounds 735: 1350-1356.

Qafoku, O., E. S. Ilton, M. E. Bowden, L. Kovarik, X. Zhang, R. K. Kukkadapu, M. H. Engelhard, C. J. Thompson, H. T. Schaef, B. P. McGrail, K. M. Rosso, and J. S. Loring. 2018. “Synthesis of Nanometer-Sized Fayalite and Magnesium-Iron(II) Mixture Olivines.” Journal of Colloid and Interface Science 515: 129-138.


McBriarty, M. E., J. A. Soltis, S. Kerisit, O. Qafoku, M. E. Bowden, E. J. Bylaska, J. J. De Yoreo, and E. S. Ilton. 2017. “Trace Uranium Partitioning in a Multiphase Nano-FeOOH System.” Environmental Science and Technology 51 (9): 4970-4977.

McGrail, B. P., H. T. Schaef, F. A. Spane, J. B. Cliff, O. Qafoku, J. A. Horner, C. J. Thompson, A. T. Owen, and C. E. Sullivan. 2017. “Field Validation of Supercritical CO2 Reactivity with Basalts.” Environmental Science and Technology Letters 4 (1): 6-10.

McGrail, B. P., H. T. Schaef, F. A. Spane, J. A. Horner, A. T. Owen, J. B. Cliff, O. Qafoku, C. J. Thompson, and E. C. Sullivan. 2017. “Wallula Basalt Pilot Demonstration Project: Post-Injection Results and Conclusions.”

Qafoku, O., C. I. Pearce, A. Neumann, L. Kovarik, M. Zhu, E. S. Ilton, M. E. Bowden, C. T. Resch, B. W. Arey, E. Arenholz, A. R. Felmy, and K. M. Rosso. 2017. “Tc(VII) and Cr(VI) Interaction with Naturally Reduced Ferruginous Smectite from a Redox Transition Zone.” Environmental Science and Technology 51 (16): 9042-9052.

Xu, J., H. Veeramani, N. P. Qafoku, G. Singh, M. V. Riquelme, A. Pruden, R. K. Kukkadapu, B. N. Gartman, and M. F. Hochella, Jr. 2017. “Efficacy of Acetate-Amended Biostimulation for Uranium Sequestration: Combined Analysis of Sediment/Groundwater Geochemistry and Bacterial Community Structure.” Applied Geochemistry 78: 172-185.

Xu, M., S. L. Riechers, E. S. Ilton, Y. Du, L. Kovarik, T. Varga, B. W. Arey, O. Qafoku, and S. Kerisit. 2017. “Manganese-Calcium Intermixing Facilitates Heteroepitaxial Growth at the 101¯4 Calcite-Water Interface.” Chemical Geology 470: 152-163.


Andersen, A., P. N. Reardon, S. S. Chacon, N. P. Qafoku, N. M. Washton, and M. Kleber. 2016. “Protein-Mineral Interactions: Molecular Dynamics Simulations Capture Importance of Variations in Mineral Surface Composition and Structure.” Langmuir 32 (24): 6194-6209.

Byrne, J. M., G. Van Der Laan, A. I. Figueroa, O. Qafoku, C. Wang, C. I. Pearce, M. Jackson, J. Feinberg, K. M. Rosso, and A. Kappler. 2016. “Size Dependent Microbial Oxidation and Reduction of Magnetite Nano-and Micro-Particles.” Scientific Reports 6.

Neeway, J. J., R. M. Asmussen, A. R. Lawter, M. E. Bowden, W. W. Lukens, D. Sarma, B. J. Riley, M. G. Kanatzidis, and N. P. Qafoku. 2016. “Removal of TcO4- from Representative Nuclear Waste Streams with Layered Potassium Metal Sulfide Materials.” Chemistry of Materials 28 (11): 3976-3983.

Wang, G., N. P. Qafoku, A. R. Lawter, M. Bowden, O. Harvey, C. Sullivan, and C. F. Brown. 2016. “Geochemical Impacts of Leaking CO2 from Subsurface Storage Reservoirs to an Unconfined Oxidizing Carbonate Aquifer.” International Journal of Greenhouse Gas Control 44: 310-322.

Williams, B. D., J. J. Neeway, M. M. V. Snyder, M. E. Bowden, J. E. Amonette, B. W. Arey, E. M. Pierce, C. F. Brown, and N. P. Qafoku. 2016. “Mineral Assemblage Transformation of a Metakaolin-Based Waste Form after Geopolymer Encapsulation.” Journal of Nuclear Materials 473: 320-332.


Felmy, A. R., O. Qafoku, B. W. Arey, L. Kovarik, J. Liu, D. Perea, and E. S. Ilton. 2015. “Enhancing Magnesite Formation at Low Temperature and High CO2 Pressure: The Impact of Seed Crystals and Minor Components.” Chemical Geology 395: 119-125.

Gartman, B. N., N. P. Qafoku, J. E. Szecsody, R. K. Kukkadapu, Z. Wang, D. M. Wellman, and M. J. Truex. 2015. “Uranium Fate in Hanford Sediment Altered by Simulated Acid Waste Solutions.” Applied Geochemistry 63: 1-9.

Qafoku, O., D. A. Dixon, K. M. Rosso, H. T. Schaef, M. E. Bowden, B. W. Arey, and A. R. Felmy. 2015. “Dynamics of Magnesite Formation at Low Temperature and High pCO2 in Aqueous Solution.” Environmental Science and Technology 49 (17): 10736-10744.

Shao, H., N. P. Qafoku, A. R. Lawter, M. E. Bowden, and C. F. Brown. 2015. “Coupled Geochemical Impacts of Leaking Co2 and Contaminants from Subsurface Storage Reservoirs on Groundwater Quality.” Environmental Science and Technology 49 (13): 8202-8209.

Xu, M., E. S. Ilton, M. H. Engelhard, O. Qafoku, A. R. Felmy, K. M. Rosso, and S. Kerisit. 2015. “Heterogeneous Growth of Cadmium and Cobalt Carbonate Phases at the 1014 Calcite Surface.” Chemical Geology 397: 24-36.


Arey, B. W., D. E. Perea, L. Kovarik, R. J. Colby, J. Liu, O. Qafoku, and A. R. Felmy. 2014. “Understanding Fayalite Chemistry Using Electron Microscopy and Atom Probe Tomography.”  20 (3): 998-999.

Neeway, J. J., N. P. Qafoku, B. D. Williams, K. Rod, M. E. Bowden, C. F. Brown, and E. M. Pierce. 2014. “Performance of the Fluidized Bed Steam Reforming Product under Hydraulically Unsaturated Conditions.” Journal of Environmental Radioactivity 131: 119-128.

Pearce, C. I., J. Liu, D. R. Baer, O. Qafoku, S. M. Heald, E. Arenholz, A. E. Grosz, J. P. McKinley, C. T. Resch, M. E. Bowden, M. H. Engelhard, and K. M. Rosso. 2014. “Characterization of Natural Titanomagnetites (Fe3-xTixO4) for Studying Heterogeneous Electron Transfer to Tc(VII) in the Hanford Subsurface.” Geochimica et Cosmochimica Acta 128: 114-127.

Qafoku, N. P., B. N. Gartman, R. K. Kukkadapu, B. W. Arey, K. H. Williams, P. J. Mouser, S. M. Heald, J. R. Bargar, N. Janot, S. Yabusaki, and P. E. Long. 2014. “Geochemical and Mineralogical Investigation of Uranium in Multi-Element Contaminated, Organic-Rich Subsurface Sediment.” Applied Geochemistry 42: 77-85.

Qafoku, O., J. Hu, N. J. Hess, M. Y. Hu, E. S. Ilton, J. Feng, B. W. Arey, and A. R. Felmy. 2014. “Formation of Submicron Magnesite During Reaction of Natural Forsterite in H2O-Saturated Supercritical CO2.” Geochimica et Cosmochimica Acta 134: 197-209.


Arey, B. W., L. Kovarik, O. Qafoku, Z. Wang, N. J. Hess, and A. R. Felmy. 2013. “Identification of Fragile Microscopic Structures During Mineral Transformations in Wet Supercritical CO2.” Microscopy and Microanalysis 19 (2): 268-275.

Veeramani, H., A. C. Scheinost, N. Monsegue, N. P. Qafoku, R. Kukkadapu, M. Newville, A. Lanzirotti, A. Pruden, M. Murayama, and M. F. Hochella. 2013. “Abiotic Reductive Immobilization of U(VI) by Biogenic Mackinawite.” Environmental Science and Technology 47 (5): 2361-2369.


Arey, B., D. Perera, L. Kovarik, O. Qafoku, A. Felmy, and B. Gorman. 2012. “Atom Probe and TEM Investigation of Natural Olivines.” Microscopy and Microanalysis 18 (S2): 658-659.

Campbell, K. M., R. K. Kukkadapu, N. P. Qafoku, A. D. Peacock, E. Lesher, K. H. Williams, J. R. Bargar, M. J. Wilkins, L. Figueroa, J. Ranville, J. A. Davis, and P. E. Long. 2012. “Geochemical, Mineralogical and Microbiological Characteristics of Sediment from a Naturally Reduced Zone in a Uranium-Contaminated Aquifer.” Applied Geochemistry 27 (8): 1499-1511.

Felmy, A. R., O. Qafoku, B. W. Arey, J. Z. Hu, M. Hu, H. Todd Schaef, E. S. Ilton, N. J. Hess, C. I. Pearce, J. Feng, and K. M. Rosso. 2012. “Reaction of Water-Saturated Supercritical CO2 with Forsterite: Evidence for Magnesite Formation at Low Temperatures.” Geochimica et Cosmochimica Acta 91: 271-282.

Loring, J. S., H. T. Schaef, R. V. F. Turcu, C. J. Thompson, Q. R. S. Miller, P. F. Martin, J. Hu, D. W. Hoyt, O. Qafoku, E. S. Ilton, A. R. Felmy, and K. M. Rosso. 2012. “In Situ Molecular Spectroscopic Evidence for CO2 Intercalation into Montmorillonite in Supercritical Carbon Dioxide.” Langmuir 28 (18): 7125-7128.

Pearce, C. I., O. Qafoku, J. Liu, E. Arenholz, S. M. Heald, R. K. Kukkadapu, C. A. Gorski, C. M. B. Henderson, and K. M. Rosso. 2012. “Synthesis and Properties of Titanomagnetite (Fe3-xTixO4) Nanoparticles: A Tunable Solid-State Fe(II/III) Redox System.” Journal of Colloid and Interface Science 387 (1): 24-38.

Qafoku, O., L. Kovarik, R. K. Kukkadapu, E. S. Ilton, B. W. Arey, J. Tucek, and A. R. Felmy. 2012. “Fayalite Dissolution and Siderite Formation in Water-Saturated Supercritical CO2.” Chemical Geology 332-333: 124-135.

Um, W., H. Chang, J. P. Icenhower, W. W. Lukens, R. Jeffrey Serne, N. Qafoku, R. K. Kukkadapu, and J. H. Westsik Jr. 2012. “Iron Oxide Waste Form for Stabilizing 99Tc.” Journal of Nuclear Materials 429 (1-3): 201-209.


Hixon, A. E., Y. J. Hu, D. I. Kaplan, R. K. Kukkadapu, H. Nitsche, O. Qafoku, and B. A. Powell. 2010. “Influence of Iron Redox Transformations on Plutonium Sorption to Sediments.” Radiochimica Acta 98 (9-11): 685-692.


Qafoku, N. P., R. K. Kukkadapu, J. P. McKinley, B. W. Arey, S. D. Kelly, C. Wang, C. T. Resch, and P. E. Long. 2009. “Uranium in Framboidal Pyrite from a Naturally Bioreduced Alluvial Sediment.” Environmental Science and Technology 43 (22): 8528-8534.


Hess, N. J., O. Qafoku, Y. Xia, D. A. Moore, and A. R. Felmy. 2008. “Thermodynamic Model for the Solubility of TcO2·xH2O in Aqueous Oxalate Systems.” Journal of Solution Chemistry 37 (11): 1471-1487.


Qafoku, N. P., O. Qafoku, C. C. Ainsworth, A. Dohnalkova, and S. G. McKinley. 2007. “Fe-Solid Phase Transformations under Highly Basic Conditions.” Applied Geochemistry 22 (9): 2054-2064.