Gray Research Group at Northwestern University

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Invention Disclosures & Patent Applications

1. Photocatalytic Composite (TiO₂/SWCNT) for Organic Chemical Oxidation (provisional patent application NU 27068, filed), Y. Yao, R. Lueptow, K.A. Gray.
2. Mixed-phase nano-structured TiO₂ composite photocatalyst for energy and energy efficiency applications, (provisional patent application NU 27093 ) G. Li & K.A. Gray.
3. Reactively sputtered TiO₂ nanocomposite thin films for photoreduction and photooxidation applications under UV and visible light, (Patent No. US 8,202,820 B2 issued 06/19/12) L. Chen, M. Graham, K.A. Gray
4. Solvent-Exfoliated Graphene-Titania Nanocomposite Photocatalysts, (provisional patent application NU2011-059), Yu Teng Liang, Baiju Vijayan, Kimberly Gray, Mark Hersam.

Journal and Peer Reviewed Publications

1. C.M.Wilke, T.Tong, J-F. Gaillard, K.A. Gray (2016). Attenuation of Microbial Stress Due to Nano-Ag and Nano-TiO₂ Interactions under Dark Conditions, Environ. Sci. Technol., 50, 11302–11310 DOI: 10.1021/acs.est.6b02271
2. M. Nolan, N.A. Deskins, K.C. Schwartzenberg, K.A. Gray (2016). Local interfacial structure influences charge localization to enhance reactivity in titania composites: Beyond the band alignment paradigm,” J Physical Chemistry C, 120, 1808-1815 DOI: 10.1021/acs.jpcc.5b12326
3. K. Bhattacharyya, W. Wu, E. Weitz, B.K. Vijayan, and K.A.Gray (2015). Probing Water and CO2 Interactions at the Surface of Calcined Titania Nanorods using IR Spectroscopy, Molecules, 20, 15469-15487 DOI: 10.3390/molecules200915469
4. Tiezheng Tong, Carolyn Wilke, Jinsong Wu, Chu Thi Thanh Binh, John J. Kelly, Jean-François Gaillard, and Kimberly A. Gray (2015). Combined toxicity of nano-ZnO and nano-TiO2: From single- to multi-ENMs systems. Environ. Sci. Technol., 49, 8113−8123 ; DOI: 10.1021.acs.est.5b02148
5. A. Ozaki, E. Adams, C.T.T. Binh, T. Tong, C. G. Peterson, J-F. Gaillard, K.A. Gray, J.J. Kelly (2015). One-time addition of nano-TiO2 triggers short-term responses in benthic bacterial communities in artificial streams, Molecular Ecology, DOI: 10.1007/s00248-015-0646-z
6. Jie Sun, Sean P. Cornelius, John Janssen, Kimberly A. Gray, Adilson E. Motter (2015). “Regularity Underlies Erratic Population Abundances in Marine Ecosystems,” J. R. Soc. Interface, 12(107): 20150235. DOI 10.1098/rsif.2015.0235
7. Baiju K. Vijayan, Kevin C. Schwarzenberg, Jinson Wu, Kimberly A. Gray (2015). Phase stability and photo-activity of CuO modified titania nanotube prepared by hydrothermal method, J. Molecular Catalysis A: Chemical, 402:23-28. DOI: 10.1016/j_molcata.2015.03.004
8. J. Cheng, A. Shereef, K.A. Gray, J. Wu (2015). Development of Hierarchically Porous Cobalt Oxide for Enhanced Photo-oxidation of Indoor Pollutants, Jour. Nanoparticle Research, 17:141.DOI: 10.1007/s11051-015-2955-z
9. C.T.T. Binh, C. Peterson, T. Tong, K.A. Gray, J-F. Gaillard, J.J. Kelly, (2015). “Comparing acute effects of a nano-TiO2 pigment on cosmopolitan freshwater phototrophic microbes using high-throughput screening,” PLoSOne, 10(4): e0125613. DOI: 10.1371/journal.pone.0125613
10. T. Tong, A.N. Hill, M.A. Alsina, J. Wu, K.Y. Shang, J.J. Kelly, K.A. Gray, and J-F. Gaillard (2015). Spectroscopic characterization of TiO2 polymorphs in wastewater treatment and sediment samples, Environ. Sci. Technol. Letters, 2, 12−18. DOI: 10.1021/ez5004023
11. S. Macksasitorn, J. Janssen, KA. Gray (2015). “PCBs refocused: Correlation of PCB concentrations in Green Bay legacy sediments with adjacent lithophilic, invasive biota,” Journal of Great Lakes Research, 41:215–221. DOI:10.1016/j.jglr.2014.12.021
12. M. Nolan, A. Iwaszuk, K.A. Gray (2014). Localisation of Photoexcited Electrons and Holes on Low Coordinated Ti and O Sites in Free and Supported TiO2 Nanoclusters, Jour. Phys. Chem, C, 118 (48), 27890–27900 DOI: 10.1021/jp508822v.
13. Todd R. Eaton, Andrew M. Boston, Anthony B. Thompson, Kimberly A. Gray, Justin M. Notestein (2014). “Counting Active Sites on TiOx-SiO2 Catalysts for Alkene Epoxidation via in situ Poisoning with Phenylphosphonic Acid,” ChemCatChem, 6:3215–3222. Article Link
14. C.T.T. Binh, T. Tong, J-F Gaillard, K.A. Gray J.J. Kelly (2014). “Acute effects of TiO2 nanomaterials on the viability and taxonomic composition of aquatic bacterial communities assessed via high-throughput screening and next generation sequencing,” PLoS ONE, 9:8:e106280. Article Link
15. T. Tong, K. Fang, S. A. Thomas, C. T. T. Binh, J. J. Kelly, K. A. Gray, and J-F Gaillard (2014). Chemical interactions between nano-ZnO and nano-TiO2 in a natural aqueous medium. Environmental Science & Technology, in press.
16. M. D. Marsolek, M. J. Kirisits, K. A. Gray, and B. E. Rittmann (2014). “Coupled photocatalytic-biodegradation of 2,4,5-trichlorophenol: effects of photolytic and photocatalytic effluent composition on bioreactor process performance, community diversity, and resistance and resilience to perturbation,” Water Research, 50:59-69.
17. T.R. Eaton, M. Campos, K.A. Gray, J.M. Notestein (2014). "Quantifying accessible sites and reactivity on titania-silica (photo)catalysts: Refining TOF calculations,” Journal of Catalysis, 309:156-165.
18. C.T.T. Binh, T. Tong, J-F Gaillard, K.A. Gray J.J. Kelly, (2013). “Common freshwater bacteria vary in their responses to short-term exposure to nano-TiO₂,” Environmental Chemistry and Toxicology, 33:317-327.
19. W. Wu, K. Bhattacharyya, K. Gray and E. Weitz (2013). “Photo-induced Reactions of Surface Bound Species on the Titania Nanotubes and Platinized Titania Nanotubes: An in-situ FTIR study,” The Journal of Physical Chemistry C, in press.
20. K. Bhattacharyya, A. Danon, B. Vijayan, K.A. Gray, P.C. Stair, E. Weitz (2013). “The role of the surface lewis acid and basic sites in the adsorption of CO2 on titania nanotubes and platinized titania nanotubes: An in situ FT-IR study,” The Journal of Physical Chemistry C, 117 (24), pp 12661–12678;
21. T. Tong, A. Shereef, J. Wu, C.T.T. Binh, J.J. Kelly, J-F Gaillard, K.A. Gray (2013). "The effects of material morphology on the acute bacterial cytotoxicity of nano-TiO₂," Environmental Science and Technology, 47, 12486-12495.
22. D. Finkelstein-Shapiro, S. J. Hurst, K. A. Gray, N. Dimitrijevic, T. Rajh, P. Tarakeshwar, V. Mujica (2013). "CO₂ pre-activation via charge transfer states of TiO₂-aminosalicylic acid complexes," Journal of Physical Chemistry Letters, 4(3):475-479.
23. T. Tong, C.T.T. Binh, J.J. Kelly, J-F Gaillard, K.A. Gray (2013). "Cytotoxicity of commercial nano-TiO₂ to Escherichia coli assessed by high-throughput screening: Effects of environmental factors," Water Research, 47 (7), 2352-2362
24. D. Finkelstein-Shapiro, C. Y.-H. Tsai, S. Li, K. A. Gray (2012). "Synthesis of high-energy anatase nanorods via an intermediate nanotube morphology," Chemical Physics Letters, 546:106-108.
25. K. N. Kalscheur, M. Rojas, C. G. Peterson, J. J. Kelly, K. A. Gray (2012). "Algal Exudates and Stream Organic Matter Influence the Structure and Function of Denitrifying Bacterial Communities, " Microbial Ecology, 64(4):881-892.
26. O. Lyandres, P. Chakthranont, D. Finkelstein-Shapiro, M. Graham, K. A. Gray (2012). "The effects of preferred orientation in sputtered TiO₂ thin films on the photooxidation efficiency of acetaldehyde," Chemistry of Materials, 24(17): 3355-3362..
27. Y.T. Liang, B. Vijayan, O. Lyandres, K.A. Gray, M.C. Hersam (2012). "The effect of dimensionality on the photocatalysis of carbon-titania nanosheet composites: Charge transfer at nanomaterial interfaces," Journal of Physical Chemistry Letters, 3:1760-1765.
28. K.N. Kalscheur, R.R. Penskar, A.D. Daley, S.M. Pechauer, C.G. Peterson, J.J. Kelly, K.A. Gray (2012), "Effects of anthropogenic inputs on the organic quality of urbanized streams," Water Research, 46: 2515-2524 DOI: 10.1016/j.watres.2012.01.043.
29. K. Schwartzenberg, K.A. Gray (2012). "Nanostructured Titania: The Current and Future Promise of Titania Nanotubes," Catalysis Science and Technology, 2 (8), 1617 - 1624.
30. Baiju K. Vijayan, Nada M. Dimitrijevic, Daniel F. Shapiro, Kimberly A. Gray (2012). "Coupling titania nanotubes and carbon nanotubes to create photocatalytic nanocomposites," ACS Catalysis 2, 223-229.
31. P.A. DeSario, J. Wu, M.E. Graham, K.A. Gray (2012). "Nanoscale structure of Ti1-xNbyO2 mixed phase thin films: Distribution of crystal phase and dopants," Journal of Materials Research, 27:944-950.
32. Alon Danon, Kaustava Bhattacharyya, Baiju K. Vijayan, Junling Lu, Dana J. Sauter, Kimberly A. Gray, Peter C. Stair, and Eric Weitz (2012). "The Effect of Reactor Materials on the Properties of Titanium Oxide Nanotubes," ACS Catalysis, 2 (1), 45-49.
33. D. Finkelstein-Shapiro, A.M. Buchbinder, B. Vijayan, K. Bhattacharyya, E. Weitz, F.M. Geiger, K.A. Gray (2011). "Elucidation of several types of binding sites for the adsorption of acetaldehyde on the surface of titania nanorods," Langmuir, 27, 14842-14848.
34. N.M. Dimitrijevic, T. Rajh, B. Vijayan, K.A. Gray (2011). "Photocatalytic Reduction of CO₂: Probing Structure of Photocatalysts and Mechanism of CO₂ Transformation," ECS Transactions, 35 (25) 167-171.
35. Y. T. Liang, B. Vijayan, K. A. Gray, M.C. Hersam (2011). "Minimizing Graphene Defects Enhances Titania Nanocomposite-Based Photocatalytic Reduction of CO₂ for improved Solar Fuel Production" Nano Letters, 11, 2865-2870.
36. P.A. DeSario, K. A. Gray (2011) "Passive Systems: Using every surface in the built environment," in Handbook of Metropolitan Sustainability: Understanding and Improving the Built Environment. F. Zeman, ed. (Woodhead Publishing Ltd), Ch. 15, in press.
37. C.G. Peterson, A.D. Daley, S.M. Hell, K.N. Kalscheur, M. Sullivan, S.L. Kufta, K.A. Gray, J.J. Kelly (2011). "Development of microalgal/bacterial-denitrifier associations in streams of contrasting anthropogenic influence," FEMS Microbiology Ecology, 77, 477-492.
38. J. Wu, S. Lo, K. Song, B. Bijayan, K.A. Gray, V.P. Dravid (2011). "Growth of rutile TiO₂ nanorods above anatase TiO₂ thin films on Si-based substrates," Journal of Materials Research, 26:1646-1652.
39. Luciana Zanella, Francesca Casadio, Kimberly A. Gray, Richard Warta, Qing Ma and Jean-François Gaillard (2011). "The Darkening of Zinc Yellow: XANES Speciation of Chromium in Artist's Paints after Light and Chemical Exposures," Journal of Analytical Atomic Spectrometry, 6, 1090-1097.
40. P. Desario , L. Chen, M.E. Graham, K.A. Gray (2011) "The effect of oxygen deficiency on the photoresponse and reactivity of titania thin films," JVST A, 29:031508 - 31515.
41. K.A.Gray (2011). "Five Myths about Nanotechnology in the Current Public Policy Debate: A science and engineering perspective," in The Nanotechnology Challenge: Creating Legal Institutions for Uncertain Risks (David Dana, editor, Cambridge Press), Sept. 2011, Ch 2, 11-60.
42. N.M. Dimitrijevic, B. Vijayan, O.G. Poluektov, T. Rajh, K.A. Gray, H. He; P. Zapol, Peter (2011) "Role of Water and Carbonates in the Photocatalytic Transformation of CO₂ to CH₄ on Titania," JACS, 133:3964-3971.
43. P.A. DeSario, R.M. Gelfand, M.E. Graham, K.A. Gray. (2011) "The effect of Nb substitution on synthesis and photo-response of TiO₂ thin films prepared via reactive magnetron sputtering." Thin Solid Films, 519:11:3562-356.
44. M. Lindsey, J.L. Schofer, P. Durango-Cohen, K.A. Gray (2011) "The Effect of Residential Location on Vehicle Miles of Travel, Energy Consumption and Greenhouse Gas Emissions: Chicago Case Study," Transportation Research, Part D, 16:1-9.
45. C. Ng, K.A. Gray (2011) "Forecasting the effects of global change scenarios on bioaccumulation patterns in Great Lakes Species," Global Change Biology, 17, 720-733 (DOI: 10.1111/j.1365-2486.2010.02299.x).
46. B. Vijayan, N.M. Dimitrijevic, J. Wu, K.A. Gray (2010) "The effects of Pt-doping on the structure and visible light photoactivity of titania nanotubes," Jour. Phys. Chem. C, 114, 21262-21269.
47. F. Casadio, S. Xie, S. Rukes, B. Myers, K. Gray, R. Warta, I. Fiedler (2010) "Electron Energy Loss Spectroscopy elucidates the elusive darkening of zinc potassium chromate in Georges Seurat's A Sunday on La Grande Jatte - 1884," Analytical and Bioanalytical Chemisry.
48. M. Lindsey, J.L. Schofer, P. Durango-Cohen, K.A. Gray (2010) "Relationship between Proximity to Transit and Ridership for Journey-to-Work Trips in Chicago," Transportation Research, Part A, 44:697-709 (doi:10.1016/j.tra.2010.07.003).
49. B. Vijayan, N. Dimitrijevic, T. Rajh, K.A. Gray. (2010) "Effect of calcination temperature on photocatalytic reduction and oxidation of hydrothermally synthesized titania nanotube," Jour. Phys. Chem. C, 14:30:12994-13002.
50. K. Schulte, P. Desario, K.A. Gray. (2010) "Effect of Crystal Phase Composition on the Reductive and Oxidative Abilities of TiO₂ Nanotubes under UV and Visible Light," Applied Catalysis B, 97:3-4:354-360.
51. S. Ciston, R.M. Lueptow, K.A. Gray (2009) "Control of Biofilm Growth on Reactive Ceramic Ultrafiltration Membranes," Journal of Membrane Science, 342, 263-268.
52. L. Chen, M.E. Graham, K.A. Gray (2009) "Nitrogen stabilized reactive sputtering of optimized TiO₂-x photocatalysts with visible light reactivity," Journal Vacuum Science & Technology, 27(4):712-715.
53. C. Ng, K.A. Gray (2009) "Tracking bioaccumulation in aquatic organisms: A dynamic model integrating life history characteristics and environmental change," Ecological Modeling, 220, 1266-1273.
54. L. Chen, M.E. Graham, G. Li, D. Gentner, K.A. Gray (2009) "Photoreduction of CO₂ by TiO₂ Nanocomposties Synthesized through Reactive DC Magnetron Sputter Deposition," Thin Solid Films, 517:5641-5645.
55. G. Li, N.M. Dimigtrijevic, L. Chen, T. Rajh, K.A. Gray (2008). "Photoactive CuO-TiO₂ Nanocomposites Prepared by a Chemical Method," Jour. Phys. Chem. C, 112, 19040-19044.
56. Y. Yao, G. Li, K.A. Gray, R.M. Lueptow (2008) "Single-walled Carbon Nanotube Facilitated Dispersion of Particulate TiO₂ on ZrO2 Ceramic Membranes," Langmuir, 24:7072-7075.
57. F. Casadio, K.A. Gray, R. Warta, I. Fiedler (2008) "Deterioration of Zinc Potassium Chromate: Elucidating the effects of paint composition and environmental conditions on chromatic alteration," ICOM Committee for Conservation, 15th Triennial Meeting, New Delhi, India (James and James Publishers) in press.
58. C.A. Ng, M.B. Berg, D.J. Jude, J. Janssen, P.M. Charlebois, L.A.N. Amaral, K.A. Gray. (2008) "Chemical amplification in an invaded food web: Seasonality and ontogeny in a high biomass, low diversity ecosystem." Environmental Toxicology and Chemistry, 27:145-154.
59. Y. Yao, G. Li, R.M. Lueptow, K.A. Gray, (2008) "Photoactive TiO₂-Carbon Nanotube Composites: Synthesis and Environmental Application," Environ. Sci. Techonol., 42:4952-4957.
60. G. Li, N.M. Dimitrijevic, L. Chen, J.M. Nichols, T. Rajh, K.A. Gray (2008) "The Important Role of Tetrahedral Ti4+ Sites in the Phase Transformation and Photocatalytic Activity of TiO₂ Nanocomposites," JACS, 130:5402-5403.
61. S. Ciston, R. Lueptow, K.A. Gray, (2008) "Biofilm Attachment Studies on Reactive Ceramic Ultrafiltration Membranes," Journal of Membrane Science, 320:101-107.
62. G. Li, S.M. Ciston, Z.V. Saponjic, Le Chen, N. Dimitrijevic, T. Rajh, K.A. Gray (2008). "Synthesizing mixed-phase TiO₂ using a hydrothermal method for photo-oxidation and photo-reduction applications," Journal of Catalysis, 253:105-110.
63. C.K. Ishida, S. Arnon, C. Peterson, J.J. Kelly, K.A. Gray, (2008) "The influence of algal community structure on denitrification rates in periphyton cultivated on artificial substrates," Microbial Ecology, 56:140-152.
64. G. Li, K.A. Gray (2007) "Visible Light Photocatalytic Properties of Anion-Doped TiO₂ Materials Prepared from a Molecular Titanium Precursor," Chemical Physics Letters, Vol 451/1-3 pp 75-79.
65. S. Arnon, C.G. Peterson, K.A. Gray, A.I. Packman. (2007) "Influence of Flow Conditions and System Geometry on Nitrate Utilization by Benthic Biofilms: Implications for Nutrient Mitigation," Environmental Science & Technology, 41:8142-8148.
66. G. Li, K.A. Gray, (2007) "The solid-solid interface: Explaining the high and unique photocatalytic reactivity of TiO₂-based nanocomposite materials," Chemical Physics, 339:1-3:173-187 (HYPERLINK "http://dx.doi.org.turing.library.northwestern.edu/10.1016/j.chemphys.2007.05.023" doi:10.1016/j.chemphys.2007.05.023).
67. G. Li, L. Chen, M. Graham, K.A. Gray, (2007) "A comparison of mixed phase titania photocatalysts prepared by physical and chemical methods: The importance of the solid-solid interface." Journal of Molecular Catalysis A: Chemical, 275:30-35.
68. S. Arnon, K.A. Gray, A.I. Packman, (2007) "Biophysicochemical process coupling controls nitrogen use by benthic biofilms." Limnol. Oceanogr. 52: 1665-1671.
69. G. Li, K.A. Gray (2007). "Preparation of Mixed-phase Titanium Dioxide Nanocomposites via Solvothermal Processing." Chemistry of Materials, 19:1143-1146.
70. S. Ciston, K.A. Gray (2007). "Photocatalysis for Water Recovery: Importance of nanostructure in reactive membrane filtration," G.I.T. Laboratory Journal, 11:36-37.
71. C. Liu, K. Nakano, E. Obuchi, T. Oike, N. Yukihira, D. Hurum, K.A. Gray (2007). "Photocatalytic decomposition of formaldehyde using titania coated lime tile," Jour. of Advanced Oxidation Technologies 10 (1): 11-16.
72. S. Arnon, A.I. Packman, C.G. Peterson, K.A. Gray (2006) "The effects of overlying velocity on periphyton structure and denitrification," Journal of Geophysical Research, 112, G01002, doi:10.1029/2006JG000235.
73. L. Chen, M.E. Graham, G. Li, K.A. Gray (2006) "Fabricating Highly Active Mixed Phase TiO₂ Photocatalysts by Reactive DC Magnetron Sputter Deposition," Thin Solid Films, 515(3):1176-1181.
74. C.K. Ishida, J.J. Kelly, K.A. Gray, (2006) "Effects of variable hydroperiods and water level fluctuations on the denitrification capacity, nitrate removal, and benthic microbial community structure in constructed wetlands," Ecological Engineering, 28:363-373.
75. T. Sirivedhin, K.A. Gray, (2006) "Factors Affecting Denitrification Rates in Experimental Wetlands: Field and Laboratory Studies," Ecological Engineering, 26:167-181.
76. D.C. Hurum, A. G. Agrios, S.E. Crist, K.A. Gray, T. Rajh, M.C. Thurnauer, (2006) "Probing reaction mechanisms in mixed phase TiO₂ by EPR," Journal of Electron Spectroscopy, 150:2-3:155-163.
77. T. Sirivedhin, K.A. Gray, (2005) "Identifying Anthropogenic Markers in Surface Waters Influenced by Treated Effluents: A Tool in Potable Water Reuse," Water Research, 39:1154-1164.
78. T. Sirivedhin, K.A. Gray, (2005) "Comparison of the Disinfection Byproduct Formation Potentials between a Wastewater Effluent and Surface Waters," Water Research, 39:1025-1036.
79. D. Hurum, K. Gray, T. Rajh, M. Thurnauer, (2005) "Recombination Pathways in the Degussa P25 Formulation of TiO₂: Surface versus Lattice Mechanisms," J.Phys.Chem B, 109:977-980.
80. A. Agrios, K. Gray, E. Weitz, (2004) "Narrow Band Irradiation of Homologous Series of Chlorophenols on TiO₂: Charge Transfer Complex Formation and Reactivity." Langmuir, 20, 5911-5917.
81. D. Hurum, K. Gray, T. Rajh, M. Thurnauer, (2004) "Photo-initiated Reactions of 2,4,6-TCP on Degussa P25 formulation TiO₂: Wavelength Sensitive Decomposition," J.Phys.Chem.B, 108:16483-16487.
82. H.J. Binns, K.A. Gray, T. Chen, M.E. Finster, M. Peneff, P. Schaefer, V. Ovsey, J. Fernandes, M. Brown, B. Dunlop, (2004) "Evaluation of Landscape Interventions to Reduce Potential Exposure to Lead-Contaminated soil in Urban Residential Yards; The Safer Yards Project," Environmental Research, 96:127-138.
83. M.E. Finster. K.A. Gray, H. Binns, (2004) "Lead Levels of Vegetables Grown in Contaminated Residential Soils: A Field Survey," Science of the Total Environment, 320, 245-257.
84. J.A. Kostel, KA. Gray A. St.Amand, (2003) "The Impact of Metal and Organic Contaminants on the Structure of Periphyton in Lotic Sediments: Observations at Various Scales," International Journal of Sediment Research, 18:2:214-222.
85. D.C. Hurum, A.G. Agrios, K.A. Gray, T. Rajh, M.C. Thurnauer, (2003) "Explaining the Enhanced Photocatalytic Activity of Mixed Phase TiO₂ Using EPR," J.PhysChemB, vol 107, pp. 4545-4549.
86. A. Agrios, K.A. Gray, E. Weitz, (2003) "Photocatalytic Transformation of 2,4,5-Trichlorophenol on TiO₂ under Sub-bandgap Illumination," Langmuir, 19, 1402-1409.
87. M. Bonifacic, K-D. Asmus, K.A. Gray, (2003) "On the Reaction of 2,4,5-Trichlorophenol with hydroxyl Radicals: New Information on Transients and their Properties," J. Phys. Chem A, 107, 1307-1312.
88. G.A. Zacheis, K.A. Gray and P.V. Kamat, (2001) "Radiation induced catalytic dechlorination of hexachlorobenzene on oxide surfaces," Journal of Physical Chemistry B, 105:4715-4720.
89. G.A. Zacheis, K.A. Gray, P.V. Kamat (2000) "Radiolytic reduction of hexachlorobenzene in surfactant solutions: A steady-state and pulse radiolysis study." Environ. Sci. Technol. 34:3401-3407.
90. J.A. Kostel, H. Wang, A. St.Amand, and K.A. Gray, (1999) "1. Use of a Novel Laboratory Stream System to Study the Ecological Impact of PCB Exposure in a Periphytic Biolayer," Water Research, 33:18:3735-3748.
91. H. Wang, J.A. Kostel, A. St.Amand, and K.A. Gray, (1999) "2. The Response of a Laboratory Stream System to PCB Exposure: Study of Periphytic and Sediment Accumulation Patterns," Water Research, 33:18:3749-3761.
92. G.A. Zacheis, K.A. Gray and P.V. Kamat, (1999) "Radiation-Induced Phenomena on Oxide Surfaces: Catalytic Degradation of Hexachlorobenzene on Alumina Nanoparticles," Journal of Physical Chemistry B, 103:2142-2150.
93. D.C. Schmelling, K.A. Gray, and P.V. Kamat, (1998) "Radiolytic Behavior of 2,4,6-Trinitrotoluene in Aqueous Solution." Environmental Science and Technology, 32:7:971-974.
94. K.A. Gray and M.R. Cleland, (1998) "Environmental Radiolysis for Soil and Sediment Treatment: Comparison of Gamma and High Energy Electron Beam Systems." Journal of Advanced Oxidation Technologies, 3:1:22-36.
95. Ulick Stafford, Kimberly A. Gray and Prashant V. Kamat, (1997) "Photocatalytic Degradation of 4-Chlorophenol. A Model." Research on Chemical Intermediates, 23:4:355-388.
96. D. C. Schmelling, K. A. Gray and P. V. Kamat, (1997) "The Impact of Solution Matrix on the Photocatalytic Degradation of TNT," Water Research, 31:6:1439-1447.
97. Ulick Stafford, Kimberly A. Gray and Prashant V. Kamat, (1997) "Photocatalytic Degradation of 4-Chlorophenol. The Effects of Varying TiO₂ Concentration and Light Wavelength," Journal of Catalysis, 167:25-32.
98. D. L. Widrig, K. A. Gray and K. S. McAuliffe, "Removal of Algal-derived Organic Material by Preozonation and Coagulation: Monitoring Changes in Organic Quality by Pyrolysis-GC-MS," (1996) Water Research, 30:11:2621-2632.
99. D. C. Schmelling, K. A. Gray and P. V. Kamat, (1996) "The Role of Reduction in the Photocatalytic Degradation of TNT," Environmental Science & Technology, 30:2547-2555.
100. Ulick Stafford, Kimberly A. Gray and Prashant Kamat, "Photocatalytic Degradation of Organic Contaminants: Halophenols and Phenols," (1996) Heterogeneous Chemistry Reviews, Vol. 3, 77-104.
101. M.S. Dieckmann and K.A. Gray, (1996) "A Comparison of the Degradation of 4-Nitrophenol via Direct and Sensitized Photocatalysis in TiO₂ Slurries," Water Research, 30:5:1169-1183.
102. R.J. Hilarides, K.A. Gray, J. Guzzetta, N. Cortellucci, C. Sommer, (1996) "The Radiolytic Degradation of 2,3,7,8-Tetrachlorodibenzo-p-dioxin on Soil: Feasibility, System Design and Economic Evaluations," Water Environment Research, 68:2:178-187.
103. K.A. Gray and R.J. Hilarides, "Radiolytic Treatment of Dioxin Contaminated Soils," (1995) Radiation Physics and Chemistry, 46:4-6:1081-1084.
104. D.C. Schmelling and K.A. Gray, "Photocatalytic Transformations and Mineralization of 2,4,6-Trinitrotoluene (TNT) in TiO₂ Slurries," (1995) Water Research, 29:12:2651-2662.
105. K.A. Gray, C.R. O'Melia, and C. Yao, (1995) "Inorganic Metal Polymers: A Comparison of Aluminum and Iron(III) Polymers for Water Treatment. I. Preparation and Characterization of Polymers," Journal of American Water Works Association 87:4:136-146.
106. R. Baretto, K.A. Gray, and K. Anders, "Photocatalytic Degradation of Methyl-tert-butyl Ether in TiO₂ slurries: A Proposed Reaction Scheme," (1995) Water Research, 29:5:1243-1248.
107. R.J. Hilarides, K.A. Gray, J. Guzzetta, N. Cortellucci, and C. Sommer, "Radiolytic Degradation of 2,3,7,8-TCDD in Artificially Contaminated Soils," (1994) Environmental Science and Technology, 28:13:2249-2258.
108. K.A. Gray and U. Stafford, "Probing Photocatalytic Reactions in Semiconductor Systems: Study of Chemical Intermediates in 4-Chlorophenol Degradation by a Variety of Methods," (1994) Research on Chemical Intermediates, 20:8:835-853.
109. R.J. Hilarides, K.A. Gray, J. Guzzetta, N. Cortellucci, and C. Sommer, (1994) "Radiolytic Degradation of Dioxin on Soil: Optimal Conditions and Economic Considerations," Environmental Progress, 13:4:263-268.
110. K. Vinodgopal, U. Stafford, K.A. Gray, and P.V. Kamat, (1994) "Electrochemically Assisted Photolysis. II. The Role of Oxygen and Reaction Intermediates in the Degradation of 4-chlorophenol on Immobilized TiO₂ Particulate Films," Journal of Physical Chemistry, 98:6797-6803.
111. Ulick Stafford, K.A. Gray and P.V. Kamat, (1994) "Radiolytic and TiO₂-assisted Photocatalytic Degradation of 4-Chlorophenol. A Comparative Study," Journal of Physical Chemistry, 98:6343-6351.
112. M.S. Dieckmann, K.A. Gray, and R.E. Zepp, (1994) "The Sensitized Photocatalysis of Azo Dyes in a Solid System: A Feasibility Study," Chemosphere, 28:5:1021-1034.
113. U. Stafford, K.A. Gray, P.V. Kamat, and A. Varma, (1993) "An in situ Investigation of Photocatalytic Degradation of 4-Chlorophenol on a TiO₂ Powder Surface By FTIR Spectroscopy," Chemical Physics Letters, 205:1:55-61.
114. M. Dieckmann, K.A. Gray, and P. Kamat, (1992) "Photocatalyzed Degradation of Adsorbed Nitrophenolic Compounds on Semiconductor Surfaces," Water Science and Technology, Vol. 25, No. 3, 277-279.
115. K.A. Gray, (1991) "Direct Filtration of Model and Natural Waters: The removal of turbidity versus natural organic carbon," Water Supply, 9, 521-525.
116. K.A. Gray, F. Bernazeau, C. Hubele, (1989) "Upgrading a slow sand filtration plant for micropollutant

Manuscripts (in review)

• K.A. Gray, D. Farr, A. Hughes, D. Dana, W. Drucker, M. Lindsey, T. K. Kirkby, K. Gong, (2011). "Living Cities: Transforming APEC's Cities into Models of Sustainability by 2030." (under consideration by Island Press).
• B. Sikora, J. Sirk, M. Lestina, K.A. Gray, M. Morowitz (2011). "Estimate of the CO₂ emissions associated with care for pediatric appendicitis in the U.S.," Environmental Science and Technology, in review.

Monographs and Book Chapters (*indicates Peer Review)

• A. Agrios, K. Gray, (2005) "Beyond Photocatalytic Environmental Remediation: Novel TiO₂ Materials and Applications," in Environmental Catalysis, V. Grassian, ed. (Marcel Dekker), Ch. 15, 369-390.
• M. Starkey, K. Gray, S.I. Chang, M. Parsek, (2004) "A Sticky Business: The EPS Matrix of Bacterial Biofilms", in Microbial Biofilms, M. Ghannoum and G. A. O'Toole, eds. (ASM Press), Chapter 10.
• B.A. Ankenman, K.A. Gray, (2001) "The Detached Plume Study: Statistical Analysis of Causative Factors in Portland Cement Manufacturing Plants." (Portland Cement Association, Skokie, Il) 112 pages.
• K.A. Gray, (2000) "The Establishment of Stream Standards for Total Organic Carbon: Scientific and Engineering Basis," testimony before Colorado Water Quality Board.
• * K.A. Gray, A.H. Simpson and K.S. McAuliffe, "Use of PY-GC-MS to Study the Nature and Behavior of NOM in Water Treatment." In Water Disinfection and Natural Organic Matter, Roger Minear and Gary Amy, eds. (ACS Symposium Series 649, Washington, D.C., 1996) 159-181.
• *R.J. Hilarides, K.A. Gray, J. Guzzetta, N. Cortellucci, and C. Sommer, "Degradation of Chlorinated Dioxins on Soil using 60Co Gamma Radiation: Considerations and Optimiation," in Chemical Oxidation: Technology for the 90's, Vol. 4, J. Roth and A. Bowers, eds. (Technomics, Lancaster, PA, 1996) 205-218.
• *D.C. Schmelling and K.A. Gray, "Photocatalytic Transformations of TNT in Titania Slurries: An Analysis of the Role of Interfacial Nitrogen Reduction Utilizing g-Radiolysis," in Chemical Oxidation: Technology for the 90's, Vol. 4, J. Roth and A. Bowers, eds. (Technomics, Lancaster, PA, 1996) 173-184.
• *U. Stafford, K.A. Gray, and P.V. Kamat, "Photocatalytic Oxidation of 4-Chlorophenol on Titanium Dioxide: A Comparison with ?-Radiolysis," in Chemical Oxidation: Technology for the 90's, Vol. 4, J. Roth and A. Bowers, eds. (Technomics, Lancaster, PA, 1996) 193-204.
• *L. Weitzman, K.A. Gray, R.W. Peters, F.K. Kauahara, and J. Verbicky, (1994), Innovative Site Remediation Technology, Vol. II: Chemical Treatment, American Academy of Environmental Engineers, Annapolis, MD, 200 p.
• *K.A. Gray, P. Kamat, U. Stafford, and M. Dieckmann, "Mechanistic Studies of Chloro- and Nitrophenolic Degradation on Semiconductor Surfaces," Environmental Aspects of Surface and Aquatic Photochemistry, D. Crosby, R. Zepp, and G. Heltz, eds., (Lewis Publishers/CRC Press, 1994) 399-408.
• D.C. Schmelling and K.A. Gray, "Feasibility of Photocatalytic Degradation of TNT as a Single or Integrated Treatment Process," TiO₂ Photocatalytic Purification and Treatment of Water and Air, David Ollis and Hussain Al-Ekabi, eds., (Elsevier Publishers, 1993), 625-632.
• K.A. Gray, U. Stafford, M.S. Dieckmann, and P. Kamat, "Mechanistic Studies in TiO₂ Systems: Photocatalytic Degradation of Chloro- and Nitrophenols," TiO₂ Photocatalytic Purification and Treatment of Water and Air, David Ollis and Hussain Al-Ekabi, eds., (Elsevier Publishers, 1993), 455-472.
• *C.R. O'Melia, K.A. Gray, C. Yao, Polymeric Metal Coagulants, American Water Works Association Research Foundations, Denver, CO, 1989.
• T.D. Waite, K.A. Gray, "Oxidation and coagulation of wastewater effluent utilizing the ferrate(VI) ion," in Chemistry for Protection of the Environment, L. Pawlowski, A.J. Verdier, and W.J. Lacy, editors (Elsevier Science Publishing Co., 1984) pp. 407-420.

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