|
|
|
IntroductionThis annual report describes the 1999 research accomplishments for the Interfacial and Processing Sciences (I&PS) directorate, one of the six research organizations in the William R. Wiley Environmental Molecular Sciences Laboratory (EMSL) at Pacific Northwest National Laboratory (PNNL). The EMSL is a U.S. Department of Energy (DOE) national scientific user facility and is the centerpiece of the DOE commitment to providing world-class experimental, theoretical, and computational capabilities for solving the nation’s environmental problems. EMSL is part of the Environmental and Health Sciences Division (EHSD) at PNNL, which operates the facility for the DOE Office of Biological and Environmental Research (BER). Of the four research divisions at PNNL, EHSD has the strongest emphasis on basic science with research focused on analytical chemistry, atmospheric sciences and global change, bio-geochemistry, materials, statistics, and the environmental molecular sciences. Although EMSL’s primary focus area is the environmental molecular sciences, our scientists and the capabilities of the facility are involved in and have an impact on work throughout EHSD and the other three PNNL research divisions—Energy, Environmental Technology, and National Security. Capabilities in the EMSL include over 100 major instrument systems for use by our resident research staff, their collaborators, and users of the EMSL. These capabilities are used to address the fundamental science that will be the basis for finding solutions to national environmental issues such as cleaning up contaminated areas at DOE sites across the country and developing "green" technologies that will reduce or eliminate future pollution production. The capabilities also are used to further our understanding of global climate change and environmental issues relevant to energy production and use and health effects resulting from exposure to contaminated environments. As a national scientific user facility and a research organization, the mission of EMSL is to:
EMSL Research EMSL research focuses on attaining a molecular-level understanding of the physical, chemical, and biological processes that underlie the most critical environmental issues facing the DOE.
EMSL staff members are key players in national research programs focused on environmental issues, such as the Environmental Management Science Program and the Natural and Accelerated Bioremediation Research Program. Both of these programs are funded and managed by DOE. The expertise of our staff and the facility’s capabilities also are contributing to research undertaken in Environmental Molecular Science Institutes (EMSI) funded by the National Science Foundation (NSF) and DOE at Columbia University and Northwestern University. Each EMSI provides a unique program for academic scientists, engineers, and students to work with colleagues from industry and national laboratories to improve understanding of how nature and technology affect environmental systems at the molecular level. Research Capabilities EMSL offers at one location a comprehensive array of state-of-the-art equipment for research in the environmental molecular sciences. These capabilities can be integrated as needed by multidisciplinary teams of scientists to address complex problems. EMSL equipment and capabilities are grouped into seven facilities:
In addition, the Environmental Molecular Sciences Collaboratory is being developed to make the EMSL facilities and capabilities more available to scientists and engineers located anywhere in the nation or in the world. Accessing the EMSL As a user facility, the EMSL supports users who are involved in both non-proprietary and proprietary research. Capabilities are available to the general scientific and engineering communities to conduct research in the environmental sciences and other areas relevant to national science and technology issues. Users gain access to the EMSL capabilities by submitting proposals, which are reviewed for:
More detailed information can be obtained via the User Info and Proposal Form links on the EMSL web site at http://www.emsl.pnl.gov. We hope you find the research highlights and other information included in this report to be interesting and informative. If you would like to receive reports describing the 1999 accomplishments of the other EMSL research directorates, please contact the associate director identified in Figure 1.1. More information about our Interfacial and Processing Sciences directorate and the organization of this report follows.
Mission The mission of the I&PS directorate is to provide an innovative, focused research capability in the areas of surface and interphasial chemistry, advanced materials synthesis and characterization, and microanalytical science that will contribute to a wide variety of primary DOE missions of the U.S. Department of Energy. I&PS researchers focus on the development and improvement of DOE site characterization, remediation, and chemical and nuclear waste management technologies, particularly those applicable to the Hanford Site. Knowledge from our research activities increases our basic understanding of complex molecular systems and leads to increased effectiveness, reduced costs, and greater confidence in remedial actions. In addition, we support development of novel materials for energy-related applications, methods for carbon dioxide reduction and sequestration, microanalytical systems for biomedical applications, and technologies to support DOE national security interests. The I&PS directorate also plays a major role in the EMSL’s role as a national scientific user facility. We provide support, training, and collaboration for on-site users for a wide variety of state-of-the-art capabilities and facilities. These capabilities include a 3.4 MeV ion beam facility for interface characterization; scanning probe microscopies, spectroelectrochemistry, electron microscopy and x-ray analysis; high-spatial/ energy resolution surface analysis; catalyst preparation, characterization and reaction engineering; a fully equipped Class 1000 clean room for microanalytical systems development and testing; inorganic, organic, polymer, and biochemical synthesis and characterization facilities; a full complement of thin film deposition and characterization facilities; and fully equipped analytical support laboratories. Last year we hosted 113 external users on-site at the EMSL including 32 from different companies. The I&PS directorate also fulfills a critical role in the PNNL/ EMSL educational mission. In 1999, we hosted 34 students (high school, undergraduate, and graduate levels), 11 postdoctoral fellows, and 3 visiting university faculty members. The I&PS directorate evolved from the amalgamation of a materials and interface group and a chemical processing group. The present organization is actively involved in a broad-range of fundamental and applied research areas. The directorate is somewhat unique in that the organization is made up of the I&PS staff as well as two research groups that are "matrixed" into the directorate from other PNNL research organizations. Consistent with the initial intentions, these matrixed staff provide a very useful interface between some of the fundamental research activities in the EMSL and the more applied research and engineering efforts in other parts of PNNL. They help I&PS achieve research activities ranging from truly fundamental to near deployment. The I&PS directorate has particular expertise in interphase structure and chemistry (D. R. Baer), including high spatial resolution surface techniques for interface characterization, mineral surface composition and dissolution processes, and spectroelectrochemistry/corrosion (M. L. Alexander, J. L. Daschbach, G. C. Dunham, M. H. Engelhard, A. S. Lea, Y. Liang, J. S. Young); microanalytical systems (J. W. Grate), including rational design of interactive materials, chemical sensor arrays, multivariate methods for information extraction, radiochemical separation and sensing methods, and bioanalytical methods and technologies (C. J. Bruckner-Lea, O. Egorov, T. L. Hart, D. Nelson); surface reactions (C. H. F. Peden), including gas/solid reaction rates, photocatalysis, growth and characterization of model oxide surfaces, and materials analysis and damage by ion bombardment (S. A. Chambers, Y. Gao, M. A. Henderson, G. S. Herman, D. E. McCready, V. S. Shutthanandan, S. Thevuthasan); nanostructural materials and colloid chemistry (G. J. Exarhos), including plasma-activated catalyst materials, surface modified mesoporous materials, colloidal phenomena and self-assembly, small-angle x-ray scattering and x-ray diffraction (M. L. Balmer, S. H. Elder, K. D. Keefer, J. Liu, M. K. Shi, Y. Su); and separations and chemical conversions (A. Y. Tonkovich), including microchannel reactors, compact fuel processing for automotive systems, electrically switched ion exchange, and catalyst and ligand design for separations (P. Berry, S. Fitzgerald, J. Hu, T. L. Hubler, M. LaMont, Y. Lin. J. L. Marco, D. Palo, S. Perry, G. L. Roberts, J. H. Sukamto, D. O. VanderWiel, Y. Wang). Research Overview This annual report describes the research and staff accomplishments of I&PS staff in 1999. The directorate is divided into five technical groups. The major research directions of each group are summarized below. However, much of the research in the I&PS directorate is highly interdisciplinary and crosses group boundaries. Consequently, the program and user research summaries that follow the group descriptions are organized topically. Interphase Chemistry. The physical and chemical properties of the region between single phases of material (the interphase) have a major influence on many characteristics of the material, including stability, atomic and ionic transport, and chemical reactivity. Interphase is the term applied when this region is many atom layers thick, while interface is used when it is a few atom layers thick. The research program of the Interphase Chemistry group includes studies of solid/solid, solid/liquid and solid/gas (or vacuum) interphase regions and has an extensive set of experimental tools to examine them. Many of the studies involving solid-liquid interfaces focus on materials stability. Included are studies involving corrosion of ancient materials, cracking of lightweight alloys, the durability of waste storage glasses, and the dissolution and growth of mineral surfaces. Programs related to solid-solid regions generally involve the creation of materials with new or unique properties. These include the control of electronic structures by interfacial engineering, the influence of interface structure on the properties of ferroelectric films, and the use of surface structures to stabilize nanoclusters. Work involving the solid-gas interface includes studies of gas reactions at mineral surfaces and remote methods of material removal for analysis. A research program using laser ablation mass spectrometry focuses on remote analysis of materials ranging from nuclear waste to the dating of Martian rocks. A critical component of this program is to understand the basic physical and chemical processes that occur at the interface between the solid sample material and the laser induced plasma. Our various interface and surface analysis laboratory capabilities perform a wide range of tests in support of user research ranging from characterization of self-assembled monolayer (SAM) films to analysis of chemical damage on fruit skins. Microsensors and Microfluidics. This research area entails a multidisciplinary effort spanning basic to applied science. Common themes involve the combination of microfabricated structures or microfluidic systems with materials and chemical processes to investigate molecular interactions, and the development of new microanalytical principles, tools, and techniques. Methods from information science are used to explore and process multivariate analytical data. Chemical microsensor development is currently focused on acoustic wave sensor arrays and optical sensing. Key areas of science in this effort include rational design of polymeric sensing materials, linear free energy models for vapor/polymer interactions, organic thin films, integrated sensor system development, and multivariate data analysis. Microfabrication capabilities exist to create or modify structures and devices. New chemometric methods designed to incorporate knowledge of molecular interactions into the analysis in order to extract more information from analytical data are under investigation. Development of microfluidic analytical tools and methods are focused in two main areas, radiochemistry and bioanalytical chemistry. A common theme in this area is the use of renewable surface techniques to deliver fresh microbeads with interactive surfaces to a separation, reaction, or sensing zone for each measurement. Thus, the interactive surface is renewed for every microanalytical procedure. Automated microanalytical separations in radiochemistry have been developed for nuclear waste characterization and medical isotope separations. Novel radionuclide sensors for water monitoring are under investigation. Bioanalytical methods are under development for complete automated sample handling for delivery to a deoxyribonucleic acid (DNA) detector or oligonucleotide array. This entails several steps including selective capture methods for cells or DNA segments from a variety of sample matrices, as well as DNA processing upstream from a chip or detector. In addition, we are developing microfluidic renewable surface techniques as a method for observing and investigating biomolecular interactions. Surface Chemistry and Catalysis. Chemical reactions taking place on the surfaces of materials underlie many processes of environmental concern. For example, the speed with which contaminants migrate in the subsurface depends markedly on reactions between these chemical species and the surfaces of soils. Other technological areas where surface chemistry plays a profound role include environmental catalysis, the development of advanced chemical sensors able to function in extremely harsh environments, predictions of long-term stability of waste containment vessels, and the development of stable, selective materials for separating the most hazardous species from toxic wastes. An understanding of the surface chemistry of minerals and oxides is a primary focus of our work both because these materials are of particular environmental interest and because, compared to metals and semiconductors, far less is known about oxide surfaces at the molecular level. As such, research is carried out with the most simple, well-defined, environmentally relevant crystallographic structures (mineral carbonates, metal oxides) where molecular theory and spectroscopy are immediately applicable. The work then progresses to materials with more complex structures, such as iron and titanium oxides with substitutional impurities. To enable these studies, we have developed and are utilizing new and unique molecular-beam epitaxy (MBE) and chemical-vapor deposition (CVD) facilities at PNNL that are dedicated to the synthesis of oxide thin-film materials. The availability of such materials is proving to be invaluable in providing well-controlled and characterized model oxide surfaces for fundamental surface chemistry studies both at PNNL and elsewhere. Nanostructural Materials and Colloid Chemistry. Fundamental research activities focus on the design, synthesis, and modification of materials comprised of hierarchical micro- or nanostructured regions that enhance selected physical properties of a material. A related element of this research program involves development of methods to characterize and control the chemical state of constituent phases in these tailored materials that influence both surface reactivity and diffusion phenomena. Work pursued here serves to underpin and drive activities comprising the applications segment of the research portfolio that derives Energy Research support through the DOE Offices of Energy Efficiency, Fossil Energy, and Environmental Management. Central to this effort is the development of novel methods to impart targeted void architectures to materials that rely on solution templating methods involving self-assembly of precursor surfactant molecules. The organic templates so formed serve as molecular scaffolds that stimulate nucleation and growth of attendant precursor ceramic phases from solution. High resolution TEM and in situ magnetic resonance methods are used to characterize the unique architectures that evolve and further the understanding of how molecular interactions among an assembly of surfactant molecules bound to a surface influence the structure of the growing ceramic phase. Materials developed here have found application to the purification of liquid waste streams and have been used as efficient separators of selected ions and molecules. This work forms the basis for the future development of smart membranes that switch molecular transport on or off in response to an applied stress. A third area of increased activity involves the development of advanced ceramic powders that are integral to pollution prevention strategies. Specially designed micrometer- or nanometer-sized powders enhance surface chemical reactivity for heterogeneous catalysis applications relevant to engine exhaust remediation technology and photocatalysis. Separations and Conversions. This research area has focused on the applied development of novel conversion and separation technologies and the fundamental materials innovations that support these technologies. The primary thrust for conversion technologies has been microtechnology, or the process intensification of chemical reactor hardware. Microreactor systems are under development for compact fuel processing applications, including automotive power generation, man portable power, and ultra small power generation for MEMS devices at the MEMS scale. The separation technologies focus on electrically switched ion exchange and ligand design for novel separations. One application area for the electrically switched ion exchange is water remediation for the forest products industries. Members of the Separations and Conversions group were recognized in FY99 with an R&D 100 Award for the Compact Microchannel Fuel Vaporizer. This breakthrough technology integrated novel catalysts into a compact microchannel reactor design before deploying the technology for industrial use. The reactor was more than an order of magnitude smaller than competing technology and is one critical component of an automotive fuel processing system. The group continues to explore additional applications of microtechnology for process intensification.
William R. Wiley Environmental Molecular Sciences Laboratory Feedback: webmaster@emsl.pnl.gov Revised: February 23, 2000 Security & Privacy PNNL-13147 |
