Southwest University of Science and Technology

About: Southwest University of Science and Technology is a education organization based out in Mianyang, China. It is known for research contribution in the topics: Adsorption & Graphene. The organization has 10017 authors who have published 8923 publications receiving 94850 citations. The organization is also known as: Xīnán Kējìdàxué.

Sulfonated polyimide/AlOOH composite membranes with decreased vanadium permeability and increased stability for vanadium redox flow battery

Abstract: A series of sulfonated polyimide (SPI)/boehmite (AlOOH) (5.0, 10.0, 15.0, 20.0 wt.%) composite membranes are fabricated by blending for vanadium redox flow battery (VRFB) application. SEM images illustrate the compatibility between SPI and AlOOH. Both EDS and XRD results verify the existence of AlOOH in the SPI/AlOOH composite membrane, and FT-IR spectrums show the interaction between SPI and AlOOH. The SPI/AlOOH membranes have improved stability in 0.1 mol L−1 VO2 + + 3.0 mol L−1 H2SO4 solutions at 40 °C than pure SPI membrane. The SPI/AlOOH-10 % membrane possesses the highest proton selectivity among all SPI/AlOOH membranes. The VRFB with the SPI/AlOOH-10 % membrane presents a higher coulombic efficiency (94.30–97.60 %) and energy efficiency (83.10–64.78 %) at the current density ranged from 20 to 80 mA cm−2 than that with Nafion 117 membrane. The open circuit voltage tests show that the SPI/AlOOH-10 % membrane has longer self-discharge time (117 h) compared with Nafion 117 (72 h). Furthermore, the cycling charge-discharge tests indicate that the SPI/AlOOH-10 % membrane has good operation stability in VRFB system. Therefore, the low-cost SPI/AlOOH membrane with excellent battery performance exhibits a great potential for application in VRFB.

Phase Transition in Octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) under Static Compression: An Application of the First-Principles Method Specialized for CHNO Solid Explosives.

Abstract: The first-principles method is challenged by accurate prediction of van der Waals interactions, which are ubiquitous in nature and crucial for determining the structure of molecules and condensed matter. We have contributed to this by constructing a set of pseudopotentials and pseudoatomic orbital basis specialized for molecular systems consisting of C/H/N/O elements. The reliability of the present method is verified from the interaction energies of 45 kinds of complexes (comparing with CCSD(T)) and the crystalline structures of 23 kinds of typical explosive solids (comparing with experiments). Using this method, we have studied the phase transition of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) under static compression up to 50 GPa. Kinetically, intramolecular deformation has priority in the competition with intermolecular packing deformation by ∼87%. A possible γ → β phase transition is found at around 2.10 GPa, and the migration of H2O has an effect of kinetically pushing this process. We ma...

Modified mineral carbonation of phosphogypsum for CO2 sequestration

Abstract: A modified phosphogypsum carbonation was systematically investigated, and ammonium acetate was used to separate Ca2+ and concentrate impurity ions from PG. The effect of technological conditions on salt-leaching and carbonation results were discussed. The calcium leaching rate was 98.1%, and the only crystal phase of salt-leaching product was quartz with granular morphology and some pores in the surface. The carbonation ratio (η) was 98.32%, and 1000 kg of phosphogypsum produced 510 kg of high-purity CaCO3 and sequestered 224 kg of CO2 under the optimized conditions. The spherical vaterite carbonation product met the recommended Chinese standard (HG/T 2226-2010). The carbonation filtrate can be reused for salt-leaching experiments. Various polymorph and morphology of CaCO3 were achieved by adjusting the carbonation temperature and ammonia dosage. The mechanism of phosphogpysum carbonation was studied by using thermodynamics research. All of this indicated that the whole procedure setup of phosphogypsum carbonation showed potential application for phosphogypsum utilization and CO2 sequestration.