Richard J. Reeder

Richard J. Reeder

Professor
Interim Deputy Provost 
Office: ESS 218      
E-mail Address: rjreeder "at" stonybrook.edu


B.S., University of Illinois, 1975 
Ph.D., University of California, Berkeley, 1980 
Faculty member at Stony Brook since 1980 
Visiting Faculty, Cambridge University, 1986-1987, 2007 

Professor Reeder's research encompasses geochemistry and mineralogy, with a focus on Earth’s surface environment.  Major goals of this work are to understand geochemically and environmentally important reaction mechanisms, especially those involving mineral-water interactions and the uptake of dissolved metals. Because of their reactive nature and widespread occurrence in sediments, soils, and rocks, carbonate and phosphate minerals are of particular interest. Closely related research addresses metal speciation and bioavailability, crystal chemistry, and phase transitions in minerals. 

Mineral-Water Interactions and Environmental Geochemistry 
Structural and chemical properties of mineral surfaces provide some of the most fundamental constraints on reactions such as sorption, coprecipitation, crystal growth, and dissolution. Reeder's research program examines the structure and behavior of mineral surfaces in order to understand the mechanisms that control the fate of metals, including toxic species and radionuclides. A particular aspect of this work concerns the relationships among bulk crystal structure, surface structure, and metal uptake mechanisms. Various experimental techniques are used for correlating element partitioning with surface structure and growth mechanisms. 

image 2 reeder
Trace elements that coprecipitate with a mineral also act as sensitive "probes" of surface sites. Research by Reeder's group on the mechanisms of trace element incorporation in carbonates, phosphates, and silicates has revealed the manner in which differences in surface structure affect trace element uptake and incorporation. Experiments involve both synthetic and natural samples, and address both the partitioning behavior and incorporation mechanisms of geochemically and environmentally important trace metals among structurally distinct surface sites, as well as the local coordination of metals on mineral surfaces and in bulk minerals. Reeder's group makes extensive use of the unique facilities at the National Synchrotron Light Source at nearby Brookhaven National Laboratory, and at the synchrotron facilities throughout the US. Synchrotron X-ray absorption spectroscopy allows direct characterization of the local environment of heavy metal species, and synchrotron X-ray fluorescence microanalysis provides spatial distribution patterns for surface-controlled incorporation. This work has shown that the size and coordination geometry of sites as well as adsorption mechanisms are fundamental factors controlling element incorporation. The results of this work have been applied to trace element diagenetic studies of carbonate rocks, to trace element records of climate change, and to the uptake and mobility of toxic metals and radionuclides in environmentally sensitive areas.

Chemical Speciation of Heavy Metals and Bioavailabilityimage 4 reeder
Some of the most serious contaminants in the environment are toxic metals and metalloids.  Common examples include lead, arsenic, chromium, mercury, and uranium.  Their partitioning between solid phases such as minerals and the aqueous phase is one of the dominant factors controlling metal mobility and bioavailability in the environment.  Prof. Reeder’s group examines these processes from a molecular perspective, with a view toward understanding chemical speciation of metals and the associated reaction mechanisms in natural and contaminated systems.  This work makes use of both lab and synchrotron-based spectroscopic and scattering techniques, including XANES and EXAFS, which offer molecular-scale information.  Information gained from this research provides the fundamental basis for remediation strategies for contaminated sites, as well as a direct link to the field of Medical Geology and human health. 


Biomineralization and Bio-inspired Synthesis
Geochemists often take cues from biology.  One important example is biomineralization, where various organisms form mineralized skeletal components having specific form and function.  Calcium carbonates and phosphates are the most common examples and occur in a variety of vertebrate and invertebrate organisms.  In the case of biogenic calcium carbonate, it is now widely appreciated that a crystalline form, such as calcite or aragonite, is not usually the first solid that forms.  The more common biomineralization pathway is via formation of an amorphous calcium carbonate (ACC) precursor that subsequently transforms to a crystalline phase.  An advantage of this approach is the ability to create a structural component, for example in a shell, having a particular shape intended for a specific function; this is made possible because ACC lacks long-range order, whereas crystals exhibit the tendency to grow in certain directions and with a specific shape.  This amorphous precursor strategy has inspired chemists and materials scientists in designing novel functional materials.  Inorganic amorphous calcium carbonate also occurs naturally, and may be important in weathering and precipitation of carbonates associated with the carbon cycle.


image 6 reederReeder’s group, in collaboration with Prof. Brian Phillips, is studying the short- and medium-range structure in amorphous biominerals and synthetic analogs using a combination of spectroscopic and scattering techniques, including pair distribution function analysis and X-ray absorption spectroscopy.  They have discovered  that hydrated ACC contains a nanoporous structure, which plays a role in its stabilization and transformation.  Students in Reeder’s group are studying the effects of chemical additives on pore structure as well as ACC stability and transformation kinetics.  These results translate to a better understanding of biomineralization mechanisms and bio-inspired synthesis.

Crystal Chemistry of Carbonates and Phosphates 
Related research pertains to structure and stability of minerals, particularly order-disorder and local structure in solid solutions in carbonates and phosphates.  Many of the solids that form in surface environments are solid solutions or exhibit extensive substitution, which affects their stability and reactivity.  This work combines X-ray scattering methods with EXAFS spectroscopy.  Particular problems include substitution mechanisms and solid solution properties for structurally incompatible components.  Other studies include studies of phase transitions in minerals and their influence on stability.

Reeder's group makes extensive use of the unique facilities at the National Synchrotron Light Source at nearby Brookhaven National Laboratory, as well as at other synchrotron facilities throughout the US. 

 

 


Selected Publications 

Goodwin, A.L., Michel, F.M., Phillips, B.L., Keen, D.A., Dove, M.T., Reeder, R.J. (2010) Nanoporous structure and medium-range order in synthetic amorphous calcium carbonate. Chem. Materials, 22, 3197-3205.

Elzinga, E.J., Tang, Y., McDonald, J., DeSisto, S., and Reeder, R.J. (2009) Macroscopic and spectroscopic characterization of selenate, selenite, and chromate adsorption at the solid-water interface of  γ-Al2O3. J. Colloid Interface Sci., 340, 153-159.

Lee, Y.J., Stephens, P.W., Tang, Y., Li, W., Phillips, B.L., Parise, J.B., and Reeder, R.J. (2009) Arsenate substitution in hydroxylapatite: Structural characterization of the Ca5(PxAs1-xO4)3OH solid solution. Am. Mineral., 94, 666-675.

Tang, Y., Chappell, H.F., Dove, M.T., Reeder, R.J., and Lee, Y.J. (2009) Zinc incorporation into hydroxylapatite. Biomaterials, 30, 2864-2872.

Tang, Y. and Reeder, R.J. (2009) Uranyl and arsenate cosorption on aluminum oxide surface. Geochim. Cosmochim. Acta, 73, 2727-2743.

Tang, Y. and Reeder, R.J. (2009) Enhanced uranium sorption on aluminum oxide pretreated with arsenate. Part I: Batch uptake behavior. Environ. Sci. Tech., 43, 4446-4451.

Tang, Y., McDonald, J., and Reeder, R.J. (2009) Enhanced uranium sorption on aluminum oxide pretreated with arsenate. Part II: Spectroscopic studies. Environ. Sci. Tech., 43, 4452-4458.

Michel, F.M., MacDonald, J. Feng, J., Phillips, B.L.,Ehm, L., Tarabrella, C., Parise, J.B., and Reeder, R.J. (2008) Structural characteristics of synthetic amorphous calcium carbonate. Chem. Materials, 20, 4720-4728.
 
Burns, F.J., Rossman, T., Vega, K., Uddin, A., Vogt, S., Lai, B., and Reeder, R.J. (2008) Mechanism of selenium-induced inhibition of arsenic-enhanced UVR carcinogenesis in mice. Environ. Health Perspect., 116, 703-708.

Tang, Y., Elzinga, E.J, Lee, Y.J., and Reeder, R.J. (2007) Coprecipitation of chromate with calcite: Batch experiments and X-ray absorption spectroscopy. Geochim. Cosmochim. Acta, 71, 1480-1493.

Hausner, D.B., Reeder, R.J., and Strongin, D.R. (2007) Humidity-induced restructuring of the calcite surface and the effect of divalent heavy metals. J. Colloid Interface Sci., 305, 101-110.

Alexandratos, V.G., Elzinga, E.J., and Reeder, R.J. (2007) Arsenate uptake by calcite: Macroscopic and spectroscopic characterization of adsorption and incorporation mechanisms. Geochim. Cosmochim. Acta, 71, 4172-4187.

Rouff, A.A., Elzinga, E.J., Reeder, R.J., and Fisher, N.S. (2006) The effect of aging and pH on Pb(II) sorption processes at the calcite-water interface. Environ. Sci. Technol., 40, 1792-1798.

Lee, Y.J. and Reeder, R.J. (2006) The role of citrate and phthalate during Co(II) coprecipitation with calcite. Geochim. Cosmochim. Acta, 70, 2253-2263.

Elzinga, E.J., Rouff, A.A., and Reeder, R.J. (2006) The long-term fate of Cu2+, Zn2+, and Pb2+ adsorption complexes at the calcite surface: An X-ray absorption spectroscopy study. Geochim. Cosmochim. Acta, 70, 2715-2725.

Lee, Y.J., Elzinga, E.J, and Reeder, R.J. (2005) Cu(II) adsorption at the calcite-water interface in the presence of natural organic matter: kinetic studies and molecular-scale characterization. Geochim. Cosmochim. Acta 69, 49-61

Lee, Y.J., Elzinga, E.J, and Reeder, R.J. (2005) Sorption mechanisms of zinc on hydroxyapatite: Systematic uptake studies and EXAFS spectroscopy analysis. Environ. Sci. Technol. 39, 4042-4048.

Phillips, B.L., Lee, Y.J., and Reeder, R.J. (2005) Organic coprecipitates with calcite: NMR spectroscopic evidence. Environ. Sci. Technol. 39, 4533-4539.

Rouff, A.A., Reeder, R.J., and Fisher, N.S. (2005) Electrolyte and pH effects on Pb(II)-calcite sorption processes: the role of the PbCO30(aq) complex.  J. Colloid Interface Sci.,286, 61-67.

Chada, V.G.R., Hausner, D.B., Strongin, D.R., Rouff, A.A., and Reeder, R.J. (2005) Divalent Cd and Pb uptake on calcite {} cleavage faces: An XPS and AFM study. J. Colloid Interface Sci. 288, 35-360.

Rouff, A.A., Elzinga, E.J., Reeder, R.J., and Fisher, N.S. (2005) The Influence of pH on the kinetics, reversibility and mechanisms of Pb(II) sorption at the calcite-water interface. Geochim. Cosmochim. Acta 69, 5173-5186.

Elzinga, E.J., Tait, C.D., Reeder, R.J., Rector, K.D., Donohoe, R.J., and Morris, D.E. (2004) Spectroscopic investigation of U(VI) sorption at the calcite-water interface. Geochim. Cosmochim. Acta 68, 2437-2448.

Rouff, A.A., Elzinga, E.J., Reeder, R.J., and Fisher, N.S. (2004) X-ray absorption spectroscopic evidence for the formation of Pb(II) inner-sphere adsorption complexes and precipitates at the calcite-water interface. Environ. Sci. Technol., 38, 1700-1707.

Reeder, R.J., Elzinga, E.J., Tait, C.D., Rector, K.D., Donohoe, R.J., and Morris, D.E. (2004) Site-specific incorporation of uranyl carbonate species at the calcite surface. Geochim. Cosmochim. Acta 68, 4799-4808.

Elzinga, E.J., Reeder, R.J., Withers, S.H., Peale, R.E., Mason, R.A., Beck, K.M., and Hess, W.P. (2002) EXAFS study of rare-earth element coordination in calcite. Geochim. Cosmochim. Acta, 66, 2875-2885.

Elzinga, E.J. and Reeder, R.J. (2002) X-ray absorption spectroscopy study of Cu2+ and Zn2+ adsorption complexes at the calcite surface: Implications for site-specific metal incorporation preferences during calcite crystal growth.  Geochim. Cosmochim. Acta, 66, 3943-3954.

Rakovan, J., Reeder, R.J., Elzinga, E.J., Cherniak, D.J., Tait, C.D., and Morris, D.E. (2002) Characterization of U(VI) in the apatite structure by X-ray absorption spectroscopy. Env. Sci. Tech., 36, 3114-3117.

Lee, Y.J., Reeder, R.J., Wenskus, R.W., and Elzinga, E.J. (2002) Structural relaxation in the MnCO3-CaCO3 solid solution: a Mn K-edge EXAFS study. Phys. Chem. Minerals, 29, 585-594.

Reeder, R.J., Nugent, M., Tait, C.D., Morris, D.E., Heald, S.M., Beck, K.M., Hess, W.P., and Lanzirotti, A. (2001) Coprecipitation of uranium(VI) with calcite: XAFS, micro-XAS, and luminescence characterization. Geochim. Cosmochim. Acta, 65, 3491-3503.

Reeder, R.J., Nugent, M., Lamble, G.M., Tait, C.D., and Morris, D.E. (2000)  Uranyl incorporation into calcite and aragonite: XAFS and luminescence studies.  Environ. Sci. Tech., 34, 638-644.

Reeder, R.J., Lamble, G.M., Northrup, P.A. (1999) XAFS study of the coordination and local relaxation around Co2+, Zn2+, Pb2+, and Ba2+ trace elements in calcite.  Am. Mineral., 84, 1049-1060.

Department of Geosciences - Earth and Space Science Building, Stony Brook, NY 11794-2100  Phone: (631) 632-8200
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