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The structures of tris(2,2'-bipyridine)cobalt(II) dichloride-2-water-ethanol, [Co/CioHjNj^jClj^HjO^HjOH (1), and tris(2,2'-bipyridine)cobalt(I) chloride-water, Co(C10H8N2)3ChH2O (2), have been determined in order to compare bonding of the high-spin d7 and high-spin d8 configurations and to better understand the electron-transfer reactivity of this couple. Compound 1 crystallizes in the hexagonal crystal system, space group P6S22, with a = 13.403 (2) Á, c = 62.566 (10) Á, and Z = 12. The structure refined to a final R value of 0.056. The coordination sphere consists of the six nitrogen atoms of the three bipyridine ligands in an octahedral arrangement about the cobalt with an average Co-N bond length of 2.128 (8) Á. One of the chloride ions is surrounded by twelve C-H-Cl hydrogen bonds involving the H3 and H3' protons on the bipyridine ligands. Compound 2 crystallizes in the orthorhombic crystal system, space group Pna2u with a = 9.713 (6) Á, b = 21.666 (10) Á, c = 13.062 (7) A, and Z = 4. The structure refined to a final R value of 0.084. The geometry of the coordination sphere of 2 is almost identical with that of 1, with an average Co-N bond length of 2.11 (2) A. Hydrogen bonding between the H3 and H3' protons on the bipyridine ligand and the chloride ion is also observed in 2. The C-H-Cl hydrogen bonding observed in these complexes and the bond length changes in 1, 2, and tris(2,2'-bipyridine)cobalt(III) are discussed and related to electron-transfer barriers for the series.

Integrating thermochemical conversion (TCC) technologies with current animal waste treatment practices can treat and reduce quantities of manure from consolidated animal feeding operations. Additionally, TCC technologies can produce value-added, renewable energy products. These products can meet heating and power needs or be catalytically converted into liquid fuels. The primary objectives of this study were to assess opportunities and obstacles in the treatment and energy conversion using currently available TCC processes. Both dry and wet livestock manures were assessed. Dry wastes like poultry litter and feedlot manures can be processed directly via pyrolysis and air/steam gasification technology. The solids in the aqueous waste streams from dairy and swine operations can undergo wet gasification or direct liquefaction processes. Alternatively, these solids can be separated and dried before conversion. Due to high ash and sulfur contents, pretreatment of manure is necessary to prevent catalyst poisoning and promote effective unit operation. While the energy input requirements for a conceptual wet gasification manure treatment system of a model swine farm is larger than a traditional anaerobic digestion operation, there are many significant advantages in implementing TCC technology including the following:  compact design; faster treatment times; reduction of odors, BOD, and pharmaceutically activated compounds; and elimination of sludge.

Commercial-scale methane (CH 4 ) extraction from natural hydrate deposits remains a challenge due to, among other factors, a poor understanding of hydrate-host sediment interactions under low-temperature and high-pressure conditions that are conducive to their existence. We report the use of synchrotron X-ray computed microtomography (CMT) to image, for the first time, time-resolved pore-scale methane CH 4 hydrate growth from an aqueous solution containing 5 wt % barium chloride (BaCl 2 ) and pressurized CH 4 hosted in glass beads, all contained in an aluminum cell with an effective volume of 3.5 mL. Multiple two-dimensional (2-D) cross-sectional images show CH 4 hydrates, with 7.5 mm resolution, distributed in patches throughout the system without dependence on distance from the cell walls. The time-resolved three-dimensional (3-D) images, constructed from the 2-D slices, exhibited pore-filling hydrate formation from dissolved CH 4 gas, similar to natural CH 4 hydrates (sI) in the marine environment. Furthermore, the 3-D images show that the aqueous phase was the wetting phase of the glass beads, i.e., the host and the formed hydrate were separated by an aqueous layer. These results provide some fundamental understanding of the nucleation phenomenon of gas hydrate formation at the pore scale. Pore-filling CH 4 hydrate growth is likely to result in a reduced bulk modulus, and thus, could affect seafloor stability during the reverse phenomenon, i.e., dissociation of natural hydrate deposits.

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Biofuels have the potential to alter the transport and agricultural sectors of decarbonizing societies. Yet, the sustainability of these fuels has been questioned in recent years in connection with food versus fuel trade-offs, carbon accounting, and land use. Recognizing the complicated playing field for current decision-makers, we examine the technical attributes, policy, and global investment activity for biofuels (primarily liquids). Differences in feedstock and fuel types are considered, in addition to policy approaches of major producer countries. Issues with recent, policy-driven trade developments are highlighted to emphasize how systemic complexities associated with sustainability must also be managed. We conclude with near-term areas to watch.

Local structure of REOFeAs (RE=La, Pr, Nd, Sm) system has been studied as a function of chemical pressure varied due to different rare-earth size. Fe K-edge extended X-ray absorption fine structure (EXAFS) measurements in the fluorescence mode has permitted to compare systematically the inter-atomic distances and their mean square relative displacements (MSRD). We find that the Fe-As bond length and the corresponding MSRD hardly show any change, suggesting the strongly covalent nature of this bond, while the Fe-Fe and Fe-RE bond lengths decrease with decreasing rare earth size. The results provide important information on the atomic correlations that could have direct implication on the superconductivity and magnetism of REOFeAs system, with the chemical pressure being a key ingredient.

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