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CHEMISTRY – Cheaper olefins . . .
Separating olefins from paraffin in petroleum wastewater is a heavy expense for the petrochemical industry. Companies are looking for cheaper techniques to recycle waste streams. Neutron scattering on the BASIS instrument at Oak Ridge National Laboratory's Spallation Neutron Source shows that olefins -- unsaturated hydrocarbons -- can be separated from paraffin efficiently and cheaply using novel silver complex-based ionic liquids synthesized at ORNL by Sheng Dai. In this hybrid olefin-paraffin separation method, the metal ions of silver or copper bond to the ionic liquid and then act as carriers for the olefins, transferring these unwanted materials through a membrane where they can be collected. In this invention, quasielastic neutron scattering provided fundamental insight into the mechanisms of olefin transport that could not be obtained through other characterization techniques. Olefins are used in the making of a variety of products, including packaging, automobile parts, synthetic rubber and nylon fibers. [Contact: Agatha Bardoel, bardoelaa@ornl.gov]
MATERIALS -- Unmasking elusive hydrogen . . .
Researchers used the SEQUOIA inelastic spectrometer at the Spallation Neutron Source to map the dynamics of hydrogen atoms in a natural crystal of muscovite. The team from the Czech and Slovak Republics compared their experimental findings with computer simulations of the material's structure and dynamics to check the accuracy of the theoretical predictions. The research represents the state of the art in combining computational and neutron scattering studies of a material. SEQUOIA was able to measure hydrogen dynamics in the low-energy ranges of the material that previously have been inaccessible because the motions of heavier atoms mask the motions of hydrogen in that region. Hydrogen dynamics in different types of micas are what distinguish one from another, and this research provides preliminary data for further studies of less well ordered but technologically more important sheet silicates. [Contact: Deborah Counce, (865) 574-0644; councedm@ornl.gov]
MATERIALS – Spintronic efficiency . . .
Spin valves are widely used in computing applications and are seen as a potentially revolutionary technology in applications such as memory chips and miniature chips and sensors. They are a part of the suite of technologies known as "spintronics," which use the magnetic property of electrons called "spin" to store and transmit data. A spin valve is composed of alternating layers of electrically conducting and non-conducting materials. Organic semiconductors are the material of choice for advanced spin valve devices, but conductivity issues have hindered their use. Researchers at ORNL's Spallation Neutron Source have discovered that inserting a barrier of lithium fluoride between layers of a spin valve improves the transmission of electrons and the magnetic dynamics of the system, significantly improving the efficiency of novel organic semiconductor spin valve systems. [Contact: Deborah Counce, (865) 574-0644; councedm@ornl.gov]
BIOMASS – Cellulose breakdown . . .
Ionic liquids have emerged as promising new solvents capable of disrupting the cellulose crystalline structure in a wide range of biomass feedstocks. Such biomass is of particular interest as a renewable and sustainable source of fuels and chemicals, and the crystallinity of the cellulose is one of the major obstacles to fermentation and yields. Researchers at ORNL pretreated four different feedstocks -- microcrystalline cellulose (Avicel), switchgrass, pine, and eucalyptus -- with an ionic liquid and found such pretreatment results in a loss of cellulose crystalline structure and the transition of the feedstock surface from cellulose I to the more readily digested cellulose II. The impact of the pretreatment on the structure was analyzed by X-ray diffraction. The impact on the surface roughness was determined by small-angle neutron scattering, using the General Purpose SANS instrument at the High Flux Isotope Reactor at ORNL. Researchers believe the results for some samples suggest another factor, likely lignin-carbohydrate complexes, also impacts cellulose breakdown. [Contact: Agatha Bardoel, bardoelaa@ornl.gov]