A5005954202- Electron and X-Ray Spectroscopy Techniques
- Semiconductor materials and devices
- Ion-surface interactions and analysis
- Advanced Chemical Physics Studies
- Advanced Electron Microscopy Techniques and Applications
- Catalytic Processes in Materials Science
- Carbon Nanotubes in Composites
- Molecular Junctions and Nanostructures
- Nanoparticles: synthesis and applications
- Graphene and Nanomaterials Applications
- Microplastics and Plastic Pollution
- Graphene research and applications
- Nanopore and Nanochannel Transport Studies
- Carbon and Quantum Dots Applications
- Electrochemical Analysis and Applications
- Environmental remediation with nanomaterials
- Polymer Surface Interaction Studies
- Atmospheric chemistry and aerosols
- Diamond and Carbon-based Materials Research
- Electrocatalysts for Energy Conversion
- Atmospheric Ozone and Climate
- Recycling and Waste Management Techniques
- Mass Spectrometry Techniques and Applications
- Quantum Dots Synthesis And Properties
- biodegradable polymer synthesis and properties
Johns Hopkins University
2015-2024
University of Baltimore
2014-2021
Tuskegee University
2019
University of Minnesota
2019
University of Wisconsin–Madison
2019
Institute of Physical Chemistry
2015
Material Sciences (United States)
2012
Environmental Protection Agency
2010
Purdue University West Lafayette
2010
Delft University of Technology
2009
As greater quantities of carbon nanotubes (CNTs) enter the environment, they will have an increasingly important effect on availability and transport aqueous contaminants. a consequence purification, deliberate surface functionalization, and/or exposure to oxidizing agents after release CNTs often contain oxides (i.e., oxygen containing functional groups). To probe influence that exert CNT sorption properties, multiwalled (MWCNTs) with varying concentrations were studied respect their...
Graphene oxide (GO) is promising in scalable production and has useful properties that include semiconducting behavior, catalytic reactivity, aqueous dispersibility. In this study, we investigated the photochemical fate of GO under environmentally relevant sunlight conditions. The results indicate readily photoreacts simulated with potential involvement electron–hole pair creation. was shown to photodisproportionate CO2, reduced materials similar (rGO) are fragmented compared starting...
Exposure of multiwalled carbon nanotubes (MWCNTs) to oxidizing acids and other oxidants introduces oxygen-containing functional groups such as hydroxyl, carboxyl, carbonyl onto the surface. This research evaluated how changes in oxygen concentration distribution influenced sorption aqueous zinc cadmium on MWCNTs. Sorption results with natural char, activated carbon, a suite MWCNTs (of varying surface content) were obtained. Results confirmed that enhances both Zn[II] Cd[II] from solution....
Grafting oxygen-containing functional groups onto carbon nanotubes (CNTs) by acid treatment improves their dispersion in aqueous solutions, but there is a lack of quantitative information on the colloidal properties oxidized CNTs. We have studied influence that pH and electrolytes determining stability multiwalled (O-MWCNTs), prepared refluxing pristine MWCNTs nitric acid. The acid-treated contained oxygen predominantly form carboxyl groups. Colloidal suspensions O-MWCNTs were low-power...
As with all nanomaterials, a large fraction of the atoms in carbon nanotubes (CNTs) reside at or near surface. Consequently, surface chemistry will play crucial role determining fate and transport CNTs aquatic environments. Frequently, oxygen-containing functional groups (surface oxides) are deliberately grafted into CNT to promote colloidal stability. To study influence that both oxygen concentration functional-group distribution have on stability multiwalled (MWCNTs), suite oxidized MWCNTs...
Bimetallic reductants are frequently more reactive toward organohalides than unamended iron and can also alter product distributions, yet a molecular-level explanation for these phenomena remains elusive. In this study, surface characterization of six iron-based bimetallic (Au/Fe, Co/Fe, Cu/Fe, Ni/Fe, Pd/Fe, Pt/Fe) revealed that displacement plating produced non-uniform overlayer metallic additive on iron. Batch studies demonstrated not all additives enhanced rates 1,1,1-trichloroethane...
As-synthesized malic acid carbon dots are found to possess photoblinking properties that outstanding and superior compared those of conventional dyes. Considering their excellent biocompatibility, suitable for super-resolution fluorescence localization microscopy under a variety conditions, as we demonstrate in fixed live trout gill epithelial cells. In addition, during imaging experiments, the so-called "excitation wavelength-dependent" emission was not observed individual as-made dots,...
Environmental context. The fate and bioavailability of engineered nanoparticles in natural aquatic systems are strongly influenced by their ability to remain dispersed water. Consequently, understanding the colloidal properties through rigorous characterisation physicochemical measurements particle stability will allow for a more accurate prediction environmental, health, safety effects systems. This review highlights some important techniques suitable assessment discusses recent findings...
Multicolor carbon dots (CDs) have been developed recently and demonstrate great potential in bio-imaging, sensing, LEDs. However, the fluorescence mechanism of their tunable colors is still under debate, efficient separation methods are challenging. Herein, we synthesized multicolor polymeric CDs through solvothermal treatment citric acid urea formamide. Automated reversed-phase column was used to achieve fractions with distinct colors, including blue, cyan, green, yellow, orange red. This...
For textiles containing nanosilver, we assessed benefit (antimicrobial efficacy) in parallel with potential to release nanosilver (impact) during multiple life cycle stages. The silver loading and method of attachment the textile highly influenced washing. Multiple sequential simulated household washing experiments for fabric swatches deionized water or without detergent showed a range release. toxicity experiment supernatants zebrafish (Danio rerio) embryos was negligible, exception very...
Nanocellulose has attracted widespread interest for applications in materials science and biomedical engineering due to its natural abundance, desirable physicochemical properties, high intrinsic mineralizability (i.e., complete biodegradability). A common strategy increase dispersibility polymer matrices is modify the hydroxyl groups on nanocellulose through covalent functionalization, but such modification strategies may affect biodegradation properties exhibited by pristine nanocellulose....
X-ray photoelectron spectroscopy (XPS) in conjunction with chemical derivatization has been developed to quantify the concentrations of hydroxyl, carboxylic acid, and carbonyl groups on carbonaceous surfaces, specifically black carbons (BCs). Control studies polymers graphite were performed establish selectivity stoichiometry each reaction toward targeted oxide. Hydroxyl successfully derivatized trifluoroacetic anhydride. Derivatization strategies using trifluoroethanol, however, had be...
The effect of 500 eV electrons on nanometer scale thick films trimethyl(methylcyclopentadienyl)platinum(IV) (MeCpPtIVMe3), were studied in situ, under ultrahigh vacuum conditions using a combination temperature-programmed desorption (TPD), X-ray photoelectron spectroscopy (XPS), mass spectrometry, and reflection absorption infrared spectroscopy. TPD results revealed the presence monolayer state, with energy >10 kJ mol−1 larger than multilayer. XPS data indicate that electron beam induced...