The aim of this investigation was to separate pyruvic acid of biotransformation solutions from lactic acid through complex extraction. For this purpose, complex extraction was investigated from model solutions. Tri-n-octanylamine (TOA) was used as the extractant. The effects of various diluents, the stoichiometry of pyruvic acid to TOA, and the initial pH of the aqueous phase on the extraction process were investigated in this study. The effects of sodium hydroxide (NaOH) and trimethylamine (TMA) on the back extraction process were also studied, respectively. The optimal conditions attained from the model solutions proved efficient on the biotransformation solutions of different concentrations. A total recovery of 71-82% of pyruvic acid was obtained, whereas 89-92% of lactic acid was removed. The purity of pyruvic acid reached 97% after the removal of TMA by a simple distillation.

The ab initio calculation and bond valence model (BVM) are employed to investigate dopant occupancy in the Ti-doped high-temperature phase Ta2O5. In this structure, there are two types of Ta atoms, which the authors denote as Ta1 locating inside oxygen octahedral and Ta2 locating inside oxygen decahedral. The 5d state electron configuration of Ta1 and Ta2 is different, the hybridization between Ta1 5d state and O 2p state is stronger than that between Ta2 and O. The chemical bonding between Ta and oxygen ions is mainly covalent. However, there is an increase of the covalent character in going from Ta1–O bond to Ta2–O bond. Both total energy method and BVM indicate that Ti substituting Ta1 is energy favorable, and this maybe due to different electronic structures of Ta1 and Ta2.

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BaSi 2 is a potential thermoelectric material because of its very low thermal conductivity. Using the full-potential linearized augmented plane-wave method and semiclassical Boltzmann theory, thermoelectric transport properties of BaSi 2 have been investigated. The calculations show that the thermoelectric properties can be remarkably improved by optimizing the carrier concentration. The linear response method within the framework of density functional theory was employed to investigate the underlying physics of heat transport. There are rather flat optical dispersion curves and low frequency of acoustic phonon modes in the phonon band structure of BaSi 2 . The low-lying optical phonon branch at the C point of the Brillouin zone (BZ) corresponds to rigid-unit vibration of the Si tetrahedron. The rigid-unit vibration mode confines the acoustic phonon modes and scatters the heat-carrying acoustic modes, leading to the low lattice thermal conductivity.

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