Vicki Helene Grassian - US grants

In this research project, supported by the Analytical and Surface Chemistry Program, Professor Grassian will study the photodissociation and photodesorption of adsorbates from oxide supported metal particles, using both tunable pulsed laser and broadband light sources. Infrared and mass spectrometry will be used to monitor the reactions of methyl halides and CO adsorbed on Pt/SiO2 and Pt/Al2O3 surfaces. The results of this research will help researchers to understand the dynamics of surface photochemistry. Measurements on high surface area supported particles will be compared with results obtained for similar systems on single crystal metal surfaces in ultra high vacuum. %%% The interaction of light with catalytic systems may be an important route to the catalytic synthesis of novel molecular species. In order to investigate the possibility and promise of photocatalysis, a detailed understanding of photoinitiated chemistry on highly dispersed oxide supported metal particles must be obtained. This research project addresses the fundamental questions underlying photocatalytic processes.

Dr. Vicki H. Grassian and other members of the Chemistry Department of University of Iowa are being supported to continue a Research Experiences for Undergraduates (REU) site in Chemistry. For the period 1993-5, ten undergraduate students will spend ten weeks each summer actively engaged in a variety of research projects. Projects cover the traditional areas of chemistry-analytical, inorganic, organic, physical and biochemistry. A unique feature of this program is the focus on women and minority students.

This Career Advancement Award (CAA) to Professor Grassian is for the investigation of fundamental photochemical reactions of molecules adsorbed on single-crystal metal surfaces. Pulsed laser, time-of-flight (TOF) mass spectrometry and infrared spectrophotometry will be used to analyze the products from photodecomposition and photodesorption reactions occuring on the surface of metal particles. In addition, the TOF instrumentation will allow the measurement of the angular and translational energy distributions of the proposed photooxidation and photohydrogenation reactions. The goal is to improve our understanding of photo-induced chemical reactions which occur on the surface of metal catalysts. %%% Career Advancement Awards allow female investigators to initiate research programs in new or innovative areas of investigation. Professor Grassian will use this CAA to expand her research into the area of photochemistry on the surface of single-crystal metal particles. The results will provide increased knowledge concerning photo-induced chemical reactions observed on catalytic surfaces.

The research program entitled "Chemical Reactions of Environmental and Atmospheric Relevance on the Surface of Oxide Particles" will be performed by Dr. Vicki Grassian from the University of Iowa and is jointly supported by the Atmospheric Chemistry and Analytical and Surface Chemistry Programs. The goal of this project is to study the heterogeneous surface chemistry occurring on oxide particles. Of particular interest is the influence of adsorbed water on the adsorption and reaction kinetics of nitric acid, sulfur dioxide and ozone. Spectroscopic and kinetic measurements will be made on these complex systems.

Gas phase reactions occuring in the atmosphere are frequently catalyzed at the surface of particulates which exist in suspended aerosols. In particular, the most abundant particulates include the oxides of silicon, aluminum and iron. This research into the fundamental gas phase reactions occuring at the surfaces of oxide particles will have direct impact on the understanding of atmospheric processes. The data obtained will be useful for global atmospheric chemistry models and for developing environmental catalysts for the reduction of hazardous chemicals.

9912191
Grassian

The University of Iowa offers an 8-week summer Research Experiences for Undergraduates

With this award from the Major Research Instrumentation (MRI) Program, the Department of Chemistry at the University of Iowa will acquire a tunable solid-state laser system for applications in atmospheric chemistry, aerosol analysis, process monitoring and reaction dynamics. This equipment will be utilized in the following applications: a) laser-based probes of heterogeneous atmospheric chemistry; b) single particle mass spectrometry in real-time; c) real-time analysis of CO in fuel cell engines; d) reaction dynamics and spectroscopy of metal ion-molecule clusters; and e) photochemistry and spectroscopy of charge/proton-transfer complexes.


A laser provides a directed beam of coherent monochromatic visible or infrared light, which enables researchers to obtain with unprecedented detail, important information about fast chemical reactions and/or the structure of molecules. Its use may enable breakthroughs in our understanding of the properties of reactive and nonreactive molecules. These studies will have an impact in a number of areas such as atmospheric chemistry and combustion chemistry.

With this award from the Major Research Instrumentation (MRI) Program, the Department of Chemistry at the University of Iowa will acquire an X-ray photoelectron spectrometer. This equipment will enhance research in a number of areas: a) novel synthetic methods for patterning silicon surfaces; b) design of molecular precursor routes to inorganic materials; c) surface characterization of atmospheric particulates; and d) characterization of iron surfaces in environmental applications.

The X-ray photoelectron spectrometer (XPS) is used for chemical analysis. It irradiates a sample with a beam of monochromatic X-rays and the energies of the resulting photoelectrons are measured and related to specific elements. XPS often plays a crucial role in defining the system under study. The work to be carried out by these investigators represents a highly coherent attack on a range of issues at the forefront of materials chemistry and environmental chemistry.

This project is an experimental laboratory investigation of the impacts of atmospheric aging on the optical properties of components of mineral dust particles as functions of spectral wavelength, particle size, shape and composition. The absorption and scattering of light by various classes of mineral dust including metal oxides, carbonates, and clays will be measured for wavelengths from 0.3 to 15 micrometers. The particles will be exposed to various physical and chemical processes designed to simulate those occurring in the atmosphere. Theoretical treatments of light-particle interactions will be employed to the fresh and aged particles in an effort to derive formulas that can be used for actual atmospheric mineral dust aerosol.

This fundamental information will improve the understanding of the impact of mineral dust on the radiation budget of the earth's atmosphere. This can lead to better predictions of the impacts of perturbations to the earth's climate system. This project will have significant student involvement, including direct support of a graduate student and postdoctoral fellow.

Abstract
CHE-0503854
Grassian/Iowa

Professor Grassian and her colleagues in the Department of Chemistry at the University of Iowa are investigating the surface chemistry of carbonates, oxides and clays of relevance to atmospheric and environmental chemistry. With the support of the Analytical and Surface Chemistry Program, they are examining the interaction of carbon dioxide with CaCO3 and CaMg(CO3)2 surfaces. Both single crystal and particulate substrates are being examined. Spectroscopy, microscopy and kinetic experiments are combined to examine the interaction of CO2 with these surfaces and with important trace molecules in the atmosphere such as N2O5, SO2, and acetic and formic acids. Important information concerning atmospheric chemistry processes and biogeochemical cycles will be obtained, as well as information regarding the environmental degradation of carbonate minerals in artworks and structural materials.

The interaction of carbon dioxide with carbonate mineral surfaces is the focus of this research project supported by the Analytical and Surface Chemistry Program. Professor Grassian and her colleagues at the University of Iowa are using spectroscopic, microscopic and kinetic probes to examine the details of this surface chemistry which has relevance to many questions of environmental importance.

With support from the Chemistry Research Instrumentation and Facilities - Multiuser Instrument Acquisition (CRIF-MU) Program, the Department of Chemistry at the University of Iowa will purchase a scanning probe microscope (SPM) with the following capabilities: atomic force and scanning tunneling microscopy (AFM and STM); magnetic force microscopy; electrochemistry capabilities; liquid attachment for controlled environments; optical microscope attachment; patterning/molecular attachment; glove box attachment; temperature control; and quantitative AFM phase imaging. The SPM will enable the following projects: a) the synthesis of bottlebrush polymers; b) assembly of monolayers on silicon and their applications in nanotechnology; c) in situ studies of surface reactions of atmospheric and environmental relevance; d) studies of hierarchical structures of nanocrystalline zeolites; e) characterization of nanoelectrode structures; and f) investigation of cellular function at single cells.

The scanning probe microscope (SPM) enables researchers to image atoms directly. The interdisciplinary studies that will be carried out using this instrument will have an impact in materials sciences, nanotechnology and environmental chemistry. In addition, a significant number of graduate and undergraduate students will gain hands-on experience with this state-of-the-art instrumentation since it will be used in both a laboratory course and in research. Finally, external users from regional universities and colleges will have access through a weekend program.

The goal of the proposed work is to understand the reactivity of iron (Fe) oxide nanoparticles in
air, water, and soil environments. Fe oxide particles in the nanometer size range (< 100 nm) are
ubiquitous in nature and their occurrence ranges from ultra-fine mineral dust in the atmosphere to
nanocrystalline precipitates in the hydrosphere. Research into the reactivity of nanoparticle Fe oxides has
been primarily aimed at understanding the bonding characteristics of atoms adsorbed at the surface. It is
now recognized, however, that the behavior of Fe in the environment is strongly influenced by bacterially
driven redox reactions, as well as the local chemistry and nature of mineral surfaces in rocks and soils,
and by the presence of water. Therefore, detailed investigations of the redox chemistry of Fe oxide
nanoparticles under conditions analogous to nature are critical to understanding the role of these tiny
particles in the cycling of Fe in the environment.
The proposed research will use advanced spectroscopic and analytical techniques, in conjunction
with selective isotope labeling, to investigate redox processes occurring at the surface of Fe oxide
nanoparticles in the presence of water. Of particular interest is the bacterially driven interaction between
aqueous Fe, and mineral and cell surfaces, as well as redox reactions occurring during (i) Fe isotope
exchange, (ii) transport of atmospheric Fe mineral dust, (iii) pollutant reduction, and (iv) microbial Fe
oxidation. The experiments will use well characterized Fe oxide nanoparticles in batch and column
reactors designed to mimic natural conditions by varying biogeochemical conditions, including microbe,
mineral, and water composition, as well as flow conditions.
Intellectual Merit. Despite the key role of Fe(III)-Fe(II) reactions in environmental and industrial
applications, heterogeneous redox reactions occurring on nanoscale Fe oxides have been largely unexplored.
This is due, in large part, to the analytical and spatial complexities of studying heterogeneous reactions of Fe
in the presence of water. The proposed methodology overcomes this obstacle by using an innovative
combination of 57Fe Mossbauer spectroscopy and high precision aqueous isotope ratio measurements to
simultaneously measure isotope specific oxidation states and concentrations of Fe at the Fe oxide-water
interface. This approach, in tandem with X-Ray photoelectron spectroscopy (XPS) and transmission electron
microscopy (TEM), will provide new information on how and where redox reactions occur on Fe oxide
nanoparticles. The synergistic blend of expertise in Fe geochemistry, microbial Fe respiration, and
atmospheric Fe mineral dust brought together with the proposed NIRT provides an unparalleled opportunity
to study redox reactions involving Fe oxide nanoparticles during multiple components of the Fe
biogeochemical cycle. Observing reactivity . particle size trends for four diverse, but related reactions
provide a powerful mechanism to identify new phenomena that are unique to oxide particles within the
nanometer size range.
Broader Impacts. An innovative combination of spectroscopic and isotopic techniques, in addition
to comprehensive mineral characterization methods, will result in an improved understanding of the behavior
of Fe oxide nanoparticles in air, water, and soil. Our findings will directly impact newly developing theories
on global carbon cycling (via microbial Fe respiration and atmospheric deposition of Fe in the ocean), as well
as challenge our current understanding of important environmental and industrial processes including
degradation of soil, sediment, and water quality, the evolution of earth.s geologic/magnetic record (via Fe
isotope biosignatures), accelerated rates of corrosion, and condensation processes (which may have led to the
origin of life on earth and biological activity on Mars). The exploratory, interdisciplinary nature of the
proposed activity will provide excellent training for graduate, undergraduate, and high school students.
Students, as well as participating scientists, will gain expertise in a variety of spectroscopic and microscopic
tools through three hands-on Nanoscale Processes in the Environment Summer Workshops. During the
workshop, students will collect, analyze, and interpret data from their own samples. Bimonthly .Fe Oxides in
the Environment. student forums will also be established at each university. The overall goal is to expose
students to new ideas and to provide a forum for the interdisciplinary discussion of students. ideas throughout
the year. Finally, a new initiative, .Geology and Art., will be launched through the Geology Museum at
U.W. Madison to educate the public about Fe nanoparticles. This NIRT addresses the NSE research and
education theme .Nanoscale Processes in the Environment..

This project involves laboratory studies of heterogeneous processes occurring on dust particles in the atmosphere. Dust represents over one half the tropospheric particle mass burden. It can be transported over trans-continental distances and has a major global impact on pollution, climate, and biogeochemistry. Heterogeneous chemistry occurring on dust significantly impacts both particle and gas phase chemistry in the atmosphere.

The ACE-Asia field campaign in 2001 was the first major study that employed the use of a single particle mass spectrometer to analyze dust chemistry. These observations serve as the inspiration for the planned laboratory kinetics studies, which will also use aerosol time-of-flight mass spectrometry (ATOFMS) for chemical analysis of the particles, along with chemical ionization mass spectrometry (CIMS) to analyze gas phase species. The reactions will occur in an aerosol flow tube with controlled particle size, reactant concentration, humidity, and reaction time. Detailed surface characterization will be performed by U. of Iowa researchers using traditional SEM/EDX (Scanning Electron Microscopy/Energy-Dispersive X-ray analysis), XPS (X-Ray Photoelectron Spectroscopy), and ATR-FTIR (Attenuated Total Reflectance/Fourier-Transform Infra Red Spectroscopy) to probe the same processes. Competitive kinetics experiments will be carried out to characterize the relative reactivity of different types of dust and sea salt with gas phase precursors, and to determine the relative importance of the factors controlling secondary product formation on dust and sea salt. In addition, the project will examine how chemical transformations induced by various acids to form soluble species affect the CCN (cloud-condensation nuclei) potential of the reacted dust particles. A thermal gradient CCN instrument will be interfaced to an ATOFMS using a counterflow virtual impactor to separate and directly measure the chemical differences between those particles that activate versus those that do not.

The kinetic information obtained from the laboratory studies will be used as input to refine regional chemistry models being developed at U. of Iowa and tested by comparing the new outputs to ACE-Asia measurements. The model will be used to develop a mechanistic picture of the heterogeneous processes studied. This information will in turn be used to help design future field campaigns to probe the findings of these lab studies under real world conditions. These studies will contribute to the training of graduate and undergraduate students in atmospheric, analytical, and environmental chemistry. The project will also further develop the quantitative abilities of single-particle mass spectrometry methods.

Vicki Grassian, University of Iowa, and Gerald Meyer, Johns Hopkins University, will cochair the NSF Chemistry Workshop on Sustainability. This workshop will engage a diverse group of established investigators in chemistry and related fields who work on various aspects of sustainability. Three critical areas for progress are new energy sources and energy stores, chemical manufacturing with reduced environmental impact, and chemical transformations of the environment. The science drivers that frame sustainability from the perspective of chemists and molecular scientists will be articulated and developed at this workshop. The workshop discussions will be widely disseminated to the chemistry community through reports and symposia.

With this award from the Chemistry Research Instrumentation and Facilities: Multi User (CRIF:MU) program, the Chemistry Department at the University of Iowa will acquire a suite of instruments to determine particle size and to characterize the surface and properties of small particles. The requested equipment includes a dynamic light scattering instrument, a scanning mobility particle sizer, an aerodynamic particle sizer, an inductively coupled plasma optical emission spectrometer and a BET surface science area analyzer. This instrumentation will be used in research projects including 1) synthesis and applications for nanocrystalline zeolites; 2) atmospheric and environmental chemistry of particles; 3) new synthetic routes to nanostructured inorganic materials; 4) particle surface modifications; 5) applications of quantum dots in biosensing, and, 6) development of new experiments in the undergraduate chemistry curriculum. The set of instruments will be incorporated into the Department of Chemistry outreach programs that bring faculty and students from regional undergraduate institutions to the University of Iowa for hands-on workshops involving advanced instrumentation not available at their home institutions.

[unreadable] DESCRIPTION (provided by applicant) [unreadable] [unreadable] Manufactured nanomaterials are found in cosmetics, lotions, coatings, and used in environmental remediation applications. Therefore, there exists a large opportunity for exposure through many different routes, thus, making it necessary to study the health implications of these materials. The primary objective of this research is to fully integrate studies of the physical and chemical properties of commercially manufactured nanoparticles with inhalation toxicological studies of these same nanoparticles to determine those properties that most significantly affect nanoparticle toxicity. Our central hypothesis is that nanoparticle physico-chemical properties differ widely among particle types and certain properties induce adverse health outcomes. Furthermore, we hypothesize that nanoparticle toxicity is influenced by the susceptibility of the individual as well as the presence of other inflammatory substances. We will address these hypotheses through a series of specific study aims designed to establish a relationship between nanoparticle physicochemical properties and health outcomes. Specific Aim 1. Evaluate nanoparticle chemical composition (bulk and surface) on nanoparticle toxicity in acute and sub-acute exposure studies. Experiments will be designed to investigate nanoparticle composition (bulk and surface) before and during and after inhalation exposure studies. Specific Aim 2. Determine the impact of nanoparticle physical morphology (agglomeration size, agglomeration state and nanoparticle shape) on nanoparticle toxicity. This study will incorporate animal inhalation studies to determine the relationship between nanoparticle agglomerate size and nanoparticle shape on toxicity. Specific Aim 3: Determine if pulmonary clearance is impaired by inhaled nanoparticles and if impaired clearance increases the risk of pulmonary infection. The pulmonary clearance mechanism, especially the ability of alveolar macrophages to clear microbes or foreign particles, can be impaired by inhaled particulates. In this aim, we will compare lung clearance rates after inhalation of nanoparticles of different composition. Specific Aim 4: Compare lung inflammation produced by co-exposure of nanoparticles with other inflammatory substances and relative to the nanoparticles alone. We plan to evaluate synergistic effects with other common aerosols present in the indoor and outdoor environments including endotoxins and sulfate aerosols (e.g. ammonium sulfate). [unreadable] [unreadable] FOR PUBLIC: Manufactured nanomaterials are becoming more widespread and can found in cosmetics, lotions, coatings, and used in environmental remediation applications. The studies described here will help answer questions as to the potential impact of manufactured nanomaterials on public health as there is clearly a lack of information in this regard. These studies will focus on determining the properties that make some nanoparticles more toxic than others. [unreadable] [unreadable] [unreadable]

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).

With this award from the Major Research Instrumentation (MRI) program, Mark Young and colleagues Vicki Grassian, and Paul Kleiber from the University of Iowa will develop a single particle aerosol mass spectrometer. The proposed aerosol mass spectrometer will acquire correlated size and chemical composition information on individual particles, sampled at atmospheric pressure and in real time. The proposed mass spectrometer will be used in a number of studies of particulate matter in the environment, including atmospheric aerosols, bioaerosols and engineered nanoparticles. These studies are expected to have an impact in a number of areas from climate science to health. The project will be carried out by a diverse group of scientists, working together in a highly interdisciplinary area.

Mass Spectrometry (MS) is one of the key analytical methods used to identify and characterize small quantities of chemical species embedded in complex matrices. The mass spectrometer developed in this award will be able to identify the chemical composition of single aerosol particles. Aerosols are important species in a number of important areas including climate science, but they remain difficult to study, as they represent only a small fraction of the mass of the atmosphere. At the same time, they can have a disproportionate impact on the chemical and physical properties of the atmosphere. Research enabled by the instrumentation to be developed in this award will help to determine the impact of aerosols on climate, atmospheric chemistry and human health. The young scientists working with the researchers on this project will obtain valuable training in the development of new kinds of sophisticated equipment -- training that will be prepare them for careers in science and technology.

The Environmental chemical Sciences (ECS) program of the Division of Chemistry will support the collaborative research project of Prof. Michelle Scherer and Prof. Vicki Grassian of the University of Iowa, and Prof. Martin St. Clair of Coe College. The collaborating investigators and their students will study sorption dynamics of organic substances on iron oxide mineral surfaces. The study will make use of advanced spectroscopic methods and computational modeling methods to interrogate this complex and important environmental interface. Advanced surface spectroscopic methods will be used to characterize the molecular level details of the adsorbed surface complexes formed on nanoscale and microscale goethite and hematite particles. The study could significantly increase our understanding at the molecular level of redox processes on the environmentally ubiquitous iron oxide surfaces. Findings from this work will benefit society by providing insights into molecular scale reactions that are important in protecting the health of the Nation's water bodies. The study will provide excellent opportunities to graduate and undergraduate students at the University of Iowa and Coe College to work on a cutting edge research project in environmental chemical sciences.

Mineral dust aerosol plays a critical role in the atmosphere. Dust affects the Earth's radiation balance by direct absorption and scattering of light across the spectrum from infrared (IR) to ultraviolet (UV). Atmospheric dust particles also serve as sites for cloud nucleation indirectly affecting albedo, and as reactive surfaces for tropospheric reactions altering the chemical balance for important gas phase species such as SO2. Correctly modeling the effects of dust in weather, climate, and air quality requires accurate information about dust loading and composition, size and shape (CSS) distributions, as well as proper treatment of dust optical (scattering and absorption) properties. Dust loading and CSS distributions can be obtained by optical remote sensing. However, remote sensing dust retrievals also depend critically on an accurate treatment of aerosol optical properties. Thus, uncertainties in dust optical properties can lead to errors in estimated dust loading, and CSS distributions with deleterious consequences for weather and air quality forecasts and climate modeling.

Intellectual merit. We will investigate dust optical properties across the IR-UV spectrum through laboratory measurements and modeling analyses. The study will focus on authentic dust samples. Aerosol extinction and light scattering properties will be analyzed by measurements of particle CSS distributions through real-time in situ single particle time-of-flight mass spectrometry and particle sizing, and various ex situ methodologies. Since the particle CSS distributions will be measured simultaneously with the optical properties, detailed comparisons with theoretical simulations will be possible, with few (or no) adjustable parameters.

The main goals of this work are to establish methods for using spectroscopic and polarimetric measurements to infer mineral dust aerosol CSS distributions, and to explore how these distributions may be altered by atmospheric aging. The qualitative insight and quantitative data provided by this work can be incorporated into remote-sensing retrieval algorithms, improving the reliability of aerosol radiative transfer models for dust retrievals and climate forcing calculations, and thus transforming our understanding of the impact of dust on atmospheric chemistry, dynamics, and climate.

Broader impacts. The proposed activities offer tremendous opportunities for post-doctoral fellows and students to develop as independent scientists. This research includes aspects of experimental aerosol science, light scattering, spectroscopy, and reaction kinetics studies, combined with an extensive theoretical modeling program. Students participate in all facets of the work, presenting their results at seminars and conferences. The PIs, through a long standing collaboration, have successfully mentored students and
post-doctors at all levels in preparation for professional careers in academia and industry. More than half of the students involved in the research program have been women or from underrepresented minorities. The program also maintains active collaborations with faculty from small colleges in state Iowa, enhancing their research and teaching.

The Environmental Chemical Sciences (ECS) program of the Division of Chemistry will support the research program of Prof. Vicki Grassian of the University of Iowa. Prof. Grassian and her students will carry out detailed mechanistic studies using different spectroscopic tools, isotope labels, microscopy and calculations to provide a clearer understanding of chemical reactions that are of atmospheric significance. Prof. Grassian and her students will study the surface photochemistry of adsorbed chromophores, in particular the nitrate ion, on different surfaces and in different chemical environments. They will also study the surface chemistry, photochemistry and redox chemistry of anthropogenic metal oxide dusts. The study is potentially transformative since it could change the way we think about the chemistry of mineral dust aerosol in the atmosphere and its impact on our climate. The project will provide excellent educational opportunities for students, including some from under represented groups, desiring to work at the forefront of environmental science.

The NSF Divisions of Chemistry (NSF/CHE) and Materials Research (NSF/DMR) will support a workshop titled "Nanomaterials and the Environment - the Chemistry and Materials Science Perspective". Co-chaired by Vicki Grassian of the University of Iowa and Robert Hamers of the University of Wisconsin, the workshop will be held in Arlington, VA on June 28-29, 2011. The workshop will engage a diverse group of established investigators from academia, US government laboratories, and leading international laboratories who work to elucidate the interactions between anthropogenic nanomaterials and the environment. The objective of the workshop is to discuss and summarize the challenges and opportunities for chemists and material scientists in this area of research in a workshop report that will be broadly disseminated to the chemistry and materials science community.

PROJECT SUMMARY Inhalation exposures of metal-based particles have been associated with severe adverse health outcomes from metal fume fever to cancer. Compared to the larger particles present in samples collected with typical industrial hygiene samplers (e.g., respirable), nanoparticles have substantially greater biological reactivity, deposition in the respiratory tract, and mobility in the body after depositing. Thus, freshly produced nanoparticles near fume sources may drive much of the observed adverse health effects, and respirable sampling may be insufficient to assess metal-based exposure risks. We have recently developed a novel personal sampler-the nanoparticle respiratory dose (NRD) sampler-and an associated analytical method that is easy to use, is inexpensive to analyze, and integrates into current personal exposure sampling strategies that can streamline the multi-step process for assessing titanium dioxide nanoparticle exposures. The work outlined in this application will expand the applicability of the NRD sampler and associated analytical methods to dramatically improve exposure assessment of a broad range of metal-based nanoparticle exposures in the workplace. With successful completion of the work proposed here, there will be many benefits, including an innovative, new sampler (Aim 1) coupled with associated analytical methods (Aim 2) applicable to assessing exposures to airborne metal-based particles. These new methodologies, validated through field studies (Aim 3), will be available for exposure assessments in routine industrial hygiene practice and in epidemiological study to better elucidate the adverse health effects that may be associated specifically with certain metal-based nanoparticle exposures. Consequently, our methods will have widespread use to assess exposures in the burgeoning field of nanotechnology or in more traditional occupational settings such as where welding occurs.

The Environmental Chemical Sciences Program in the Chemistry Division at the National Science Foundation supports the research of Professor Vicki H. Grassian at the University Iowa that will focus on the chemistry and photochemistry of mineral dust and metal-containing particles with trace atmospheric gases at the gas-solid and liquid-solid interface. The chemistry that occurs on these surfaces can alter gas phase concentrations of key atmospheric constituents as well as significantly change the physicochemical properties of the particles. In the environment, these interfaces are present as both aerosol and stationary surfaces. In the proposed studies, reactions of atmospheric gases with components of mineral dust and metal-containing particles are investigated to better understand the chemistry of the troposphere and the impact that these reactions have on the environment. Several different aspects will be investigated and include the heterogeneous chemistry of organic acids with mineral dust particles, the heterogeneous chemistry of atmospheric gases on photoactive components of mineral dust aerosol and surface reactions of anthropogenic metal-containing oxide particles, which are components of atmospheric aerosol as well as stationary surfaces. These reactions take place under different regimes of water activity and, therefore, different phases of water including adsorbed water at the gas-solid interface and liquid water at the liquid-solid interface.

The proposed activities focus on better understanding the fundamental chemistry that occurs at aerosol and stationary particle surfaces. Without these types of fundamental studies, there would be little information to incorporate into atmospheric and environmental model simulations and there would be little understanding of this potentially important reaction chemistry that may impact the environment. Besides broader impacts related to better understanding the natural and human-impacted environment, another important component of this research is in the educational and outreach activities that are proposed. These include training of undergraduate and graduate students. The PI has a research program that attracts a diverse group of students including many women and underrepresented minorities. Outreach activities include the development of hands-on activities for the broader public that spans K-12 students and their parents. The PI is leading efforts to expand and enhance the effectiveness of STEM (Science, Technology, Engineering and Mathematics) outreach and education in departments and centers within the College of Liberal Arts and Sciences at the University of Iowa.

CBET - 1441457
This proposal is to conduct a workshop to examine fundamental science needs in NanoEHS. Research in this topic has reached a plateau of understanding by using fundamental testing methods. New approaches to deeper scientific questions are needed. The workshop will identify new questions in order to bring a better understanding of the interactions of nanomaterials with living systems.

The goals of the workshop are as follows:
1. Engage a broad range of participants to focus on the theme of the workshop topic NanoEHS: Fundamental Science Needs
2. Identify areas where fundamental studies are needed to better understand NanoEHS.
3. Identify challenges and opportunities in understanding NanoEHS: Fundamental Science Needs, i.e. identify problems, techniques and methods including, but not limited to, the role of computation and theory, size-dependent behavior for very small particles such as quantum size effects, and surface structure.
4. Articulate the importance of fundamental physics and chemistry within interdisciplinary approaches to NanoEHS: Fundamental Science Needs and identify opportunities for collaboration.
5. Prepare a manuscript to a journal that summarizes and highlights the workshop discussion and findings.
6. Disseminate workshop findings further in a symposium at an upcoming Sustainable Nanotechnology Organization (SNO) Meeting or some other appropriate meeting venue.

Carbonaceous atmospheric aerosols, including black and brown carbon, impact climate through altering the optical properties of the atmosphere, and also by themselves undergoing further photochemical oxidation, in a poorly understood manner. This in turn may alter their own optical properties. The overall goal of this work is to improve the scientific basis for quantitatively modeling organic aerosol radiative effects. The results have application in remote sensing data retrieval algorithms, improving the reliability of radiative transfer models for aerosol and climate forcing calculations, and better understanding the impact of brown carbon (BrC) aerosol may have on atmospheric chemistry and climate.

In previous work, University of Iowa researchers developed specialized laboratory optical capabilities to measure dust aerosol optical properties over the UV-Vis-IR spectrum, and have explored how physicochemical processing of aerosols alters those properties. Here they will further extend their experimental capabilities with a highly sensitive technique, cavity ring down laser spectroscopy (CRDS). This will be used to precisely measure the optical properties of the brown carbon (BrC) fraction of ambient and laboratory mimics of organic aerosols, across the visible and the mid-IR spectral range. How those properties may change as a result of UV photochemical processing will be further studied.

Abstract

CBET - 1424502
Vicki H. Grassian

Overview:

The challenges in understanding the environmental health and safety of nanomaterials (NanoEHS)are many but several fundamental issues in particular remain critical from a scientific perspective.

In fact, it has become apparent that progress will be limited without studies to address these issues.

Intellectual Merit:

This EAGER proposal will address several critical needs in a concentrated program with specific objectives, hypotheses and goals. These critical areas include:

1. The nature of the surface of nanomaterials in biological media

2. The role of the core in surface functionalized nanoparticles

3. The unique behavior imparted to very small nanoparticles that is not just due to physical size but instead due to quantum and other intrinsic size dependent electronic effects.

A series of targeted experiments are proposed to address these needs. These experiments are feasible and will provide the necessary results to define a framework to address the issues discussed in this proposal. In these experiments, nanoparticles will be covered using different surface functionalities including proteins. We will conduct these studies in different media relevant to understanding the toxicity of these particles, i.e. several simulated biological media of different pH to reflect both stomach and lung fluids. Furthermore, we can quantify the amount of dissolution and ROS production in each of these and as a function of particle
size, within a size range where quantum confinement is important and outside of that size range where bulk properties of electronic state structure, e.g. the band gap, are relevant.

Broader Impacts:

There are several broader impacts and translational aspects of the proposed research. First, the proposed studies are designed to gain better insight into the environmental and health impacts of nanomaterials. These studies will contribute to the growing database on the potential environmental and health implications of nanoscience and nanotechnology. This society relevant research is designed to address potential environmental problems for the nanotechnology industry. Therefore overall it has the potential to provide for the greater good of the public and consumers. The proposed activities provide an opportunity to train students in a highly interdisciplinary research area that involves environmental science and engineering, chemistry, nanoscience, colloid and surface chemistry. The PI has a track record of successfully mentoring students at all levels from high school to postdoctoral associates and visiting research scientists and will continue this effort to mentor the next generation of scientists and engineers. Many of the students are from underrepresented groups in science and engineering including a large percentage of women (more than 60%) and minorities including students on free and reduced lunch programs and typically more diverse student populations. Funds from this NSF
grant will be used to train graduate and undergraduate students to better engage these elementary students as well as the public in science and engineering.

1509432 (Mason)

Chemical looping combustion (CLC) is an emerging gaseous fuel combustion method in which carbon dioxide (CO2) can be separated from other components in the flue gas, enabling a low-cost and efficient separation and capture of CO2. The potential success of this project will help avoid negative impact on the earth's atmosphere and climate. The proposed activities will also promote training and learning activities by involving undergraduate and graduate students in research.

The knowledge gap is known to exist among molecular-level details about the surface science of oxygen carriers of CLC. While candidate batch studies have helped identify carriers, details of structure-reactivity relationships and the intermediate heterogeneous steps involved in the fuel oxidation are yet unknown. The proposed study aims to enhance the understanding of the fundamental reaction mechanisms involved in important heterogeneous processes of CLC and related catalytic applications. The thermodynamic stability of oxygen carriers will be assessed through experimental and theoretical methods and trends between carrier structure, composition, durability, and reactivity will be identified. The knowledge thus gained may drive the future rational design of materials for CLC and related applications. The methane fuel and its C-H bond activation related to many other reaction activities will be studied. Chemical synthesis and the replacement of petrochemical feed stocks by alkanes will also be investigated, expanding the potential impact of this project.

In this project funded by the Environmental Chemical Sciences Program in the Chemistry Division at the National Science Foundation, Professor Vicki H. Grassian of the University of California San Diego is investigating how metal-based nanomaterials change and transform in the environment. The proposed activities focus on molecular-based studies to better understand chemical changes in metal, metal oxide and metal sulfide nanoparticles in the environment. Although in the past decade, a number of studies have focused on environmental studies of nanoparticles in their native states, while only a few studies have focused on the molecular details of how nanoparticles can change due to chemical processing in the environment. Nanoparticles can age and undergo transformations under ambient conditions of temperature, relative humidity and in the presence of solar radiation. As these materials age and transform, their properties are altered making it difficult to identify structure?property?function and structure?property?hazard relationships. This research studies the impact of nanoparticle in the environment as well their interactions with biomolecules and biological systems. The broader impact of these studies advance the goals of sustainable nanotechnology and provide a foundation for broadening participation and training and engaging students at all levels through research, teaching and outreach activities. These studies provide students with an opportunity to engage in a highly interdisciplinary research area that involves environmental science, nanoscience, engineering, colloid science, materials and surface chemistry.

This research program studies the cxidation of metal and metal sulfide nanoparticles in humid and aqueous environments, carbonate formation of metal oxide nanoparticles in humid environments, and surface ligand reactions (adsorption and displacement) on nanoparticles in aqueous environments. These studies are used to better understand the potential environmental and health implications of nanoscience and nanotechnology and contribute to answering questions concerning the transformation and fate of manufactured nanomaterials. As nanomaterials age and transform, their properties are altered making it difficult to identify structure-property-function and structure-property-hazard relationships. Therefore aging impacts their behavior in the environment as well their interactions with biomolecules and biological systems. In particular, the proposed activities focus on better understanding transformations of metal, metal oxide and metal sulfide nanoparticles (including Cu, CuO, CuS, Ag2S, ZnO ZnS and TiO2) on a molecular level and how these processes impact nanoparticle physicochemical properties important in the environmental, health, and safety (EHS) considerations of these materials.

The Environmental Chemical Sciences Program in the Chemistry Division at the National Science Foundation supports the research of Professor Vicki H. Grassian at the University Iowa that will focus on the chemistry and photochemistry of mineral dust and metal-containing particles with trace atmospheric gases at the gas-solid and liquid-solid interface. The chemistry that occurs on these surfaces can alter gas phase concentrations of key atmospheric constituents as well as significantly change the physicochemical properties of the particles. In the environment, these interfaces are present as both aerosol and stationary surfaces. In the proposed studies, reactions of atmospheric gases with components of mineral dust and metal-containing particles are investigated to better understand the chemistry of the troposphere and the impact that these reactions have on the environment. Several different aspects will be investigated and include the heterogeneous chemistry of organic acids with mineral dust particles, the heterogeneous chemistry of atmospheric gases on photoactive components of mineral dust aerosol and surface reactions of anthropogenic metal-containing oxide particles, which are components of atmospheric aerosol as well as stationary surfaces. These reactions take place under different regimes of water activity and, therefore, different phases of water including adsorbed water at the gas-solid interface and liquid water at the liquid-solid interface.

The proposed activities focus on better understanding the fundamental chemistry that occurs at aerosol and stationary particle surfaces. Without these types of fundamental studies, there would be little information to incorporate into atmospheric and environmental model simulations and there would be little understanding of this potentially important reaction chemistry that may impact the environment. Besides broader impacts related to better understanding the natural and human-impacted environment, another important component of this research is in the educational and outreach activities that are proposed. These include training of undergraduate and graduate students. The PI has a research program that attracts a diverse group of students including many women and underrepresented minorities. Outreach activities include the development of hands-on activities for the broader public that spans K-12 students and their parents. The PI is leading efforts to expand and enhance the effectiveness of STEM (Science, Technology, Engineering and Mathematics) outreach and education in departments and centers within the College of Liberal Arts and Sciences at the University of Iowa.

This project focuses on laboratory studies to better understand particulate sulfate formation from sulfur dioxide oxidation in the atmosphere. A major focus of the proposed studies will be to quantify rates and extent of sulfate formation in multiphase pathways involving mineral dust and other metal-containing aerosols as a function of pH, temperature and light.

The mechanisms for sulfate formation that will be investigated in a series of laboratory studies that include the: (1) catalytic effects of transition metal ions present in mineral and anthropogenic metal-containing dusts; (2) enhanced sulfate formation in the presence of photoactive semiconductor oxides; and (3) role of organic compounds in mineral mediated sulfate processes. In addition, new methods to investigate the chemistry within individual cloud droplets will be developed, including an optical tweezer with cavity enhanced Raman spectroscopy to investigate sulfur oxidation chemistry within micron sized single droplets containing a dust inclusion. The experiments will be done in the presence and absence of atmospherically important organic species that can react to yield organosulfates. This project will also assess the importance of surface reactivity versus bulk reactivity, important for modeling cloud processes.

This award is supported by the Major Research Instrumentation (MRI) and the Chemistry Research Instrumentation (CRIF) Programs. Professor Wei Xiong from University of California San Diego and colleagues Vicki Grassian, Neal Devaraj and Ping Liu have developed an ultrafast, one-dimensional/two-dimensional sum frequency generation (1D/2D SFG) spectromicroscope. The microscope employs a laser to probe a sample. This produces a signal (or image) observed by the microscope. The spectral image provides information on the physical and chemical properties of the sample. It is used to probe interfaces, for example, the surface of aerosol particles. Another use is to study the structure of water in confined spaces such as in water purification materials. It is used to pinpoint domains where ice nucleation occurs. Development of artificial retinas and wearable solar cells are applications which can benefit from this instrument. Investigation of these and other processes leads to a better understanding of how to improve them or ameliorate undue consequences. Graduate students are involved with development and application of the instrument, receiving training in an important skill sought by commercial instrument firms.

The instrument is used in a variety of investigations. Water purification materials are being studied. The electrochemical interface of energy storage devices (for example, lithium batteries) is being explored. Aerosols surfaces are receiving attention to understand formation mechanisms. Materials which have heterogeneous surfaces are better understood using the microscope, for example biological fibrils. It is being used to study artificial cells and neural networks. Investigators at the University of California, Irvine and Spelman College have projects using the instrument.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

While nanotechnology is revolutionizing many industry sectors and having significant impact to our daily lives, investigating the potential negative impacts of nanomaterials becomes ever more important. Most studies that focus on understanding potential health effects are carried out with cells cultured in a petri-dish. While such studies have provided a wealth of information about the importance of nanomaterial's physical, mechanical, and chemical properties in toxicity to cells, they inform less about the interactions of the nanoparticles with human tissues and organs. This project aims to create an engineered 3-dimensional human heart tissue model generated by a novel bioprinting technique, and to use this model to study the impact of nanoparticles on the heart. Success of this this project will eliminate the need for expensive animal model systems in studies of tissue and organ toxicity to nanomaterials. The highly interdisciplinary nature of the project will involve training students across the traditional boundaries, offering exciting topics including bioprinting, tissue engineering, nanotechnology, and biological interactions of nanoparticles. Also, the project will facilitate training broadly across multiple stages of professional and academic development by including graduate students, undergraduate students, and high school students of diverse backgrounds.

Technically, this project will be the first attempt in the field to investigate how nanoparticles interact with 3-dimensional human heart tissues, created by 3-dimensional bioprinting. The first research task aims to establish the bioprinted microscale human heart tissue model and evaluate cell alignment, morphology, gene expression, and cardiac function. The second research task will focus on the synthesis of a suite of monodispersed nanoparticles with varying compositions and surface coatings. Assessment of nano-cardio interactions will be carried out to investigate the effects of these nanoparticles on cell viability, morphology, gene expression, and cardiac force output. From this project, the feasibility of using these engineered human tissue models for nanotoxicity studies will be established. The project is of high-risk. But if successful, the outcomes of the project will lead to high reward since it will provide significant insights into the biocompatibility of nanoparticles to 3-dimensional human tissues. Using human induced pluripotent stem cells derived cardiomyocytes, the project will further reveal individual effects of these nanoparticles. The investigators are well situated and uniquely positioned to tackle these issues. The principal investigator is a pioneer in 3-dimensional bioprinting with an excellent track record for cutting-edge research in biomaterials, bioprinting, and tissue engineering. The co-principal investigator is a leading expert in studying the environmental and health implications of nanomaterials. Such a unique collaboration will lead to transformative results. The highly interdisciplinary nature of the project will enable student training across the traditional boundaries, offering exciting topics including biomanufacturing, nanotechnology and biological interactions of nanoparticles. Also, the project will facilitate training graduate students, undergraduate students, and high school students of diverse backgrounds.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

This award from the Environmental Chemical Sciences Program in the NSF Division of Chemistry supports Professor Vicky Grassian at the University of California, San Diego. Professor Grassian and her team investigate the role of aerosols, in particular, their interactions with different gases in the atmosphere from both natural and pollution sources. Aerosols are solid or liquid particles suspended in air. They are an important component of the Earth?s atmosphere and can impact human health and climate. This project investigates the chemical reactions of mineral dust aerosols, a class of aerosols from windblown soils and desert regions that circulate around the globe. Understanding the interaction of mineral dust aerosol with gases increases our knowledge of the different components that make up the atmosphere and the air we breathe. Other broader impacts include the training of undergraduate and graduate students. Professor Grassian has a research program that attracts a large and diverse number of students including many women and underrepresented minorities. Additionally, educational and outreach activities for the broader public will be developed. Dr. Grassian leads efforts to expand and enhance the effectiveness of outreach activities including further development of hands-on activities for the broader public that span K-12 students including activities that relate increase in volatile organic emissions to familiar consumer products.
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This project focuses on laboratory studies of reactions of volatile and semi-volatile organic compounds with mineral dust aerosol, an important component of the Earth?s atmosphere. The organic compounds include trace atmospheric gases termed volatile chemical products (VCPs), which recently have been identified as a class of compounds that comes predominantly from industrial sources. A multi-technique, molecule-based approach employing mass spectrometry and vibrational spectroscopy is used to probe mechanistic details of surface adsorption and subsequent reactions of the adsorbed organic compounds with acidic gases and oxidants. The research project identifies how mechanisms for these reactions change as a function of relative humidity and the presence of adsorbed water. The project also determines how the different components of mineral dust aerosol impact its reactivity. New products formed in these reactions are being characterized. This research aims to provide new insights and a better understanding of the heterogeneous and multiphase chemistry of volatile and semi-volatile organic compounds with mineral dust aerosols from the perspective of fundamental molecular processes as well as potential global impacts.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.