Bismuth oxybromide（BiOBr） with a hierarchical microcube morphology was successfully synthesized via microwave-assisted ionothermal self-assembly method. The as-obtained BiOBr was composed of regular multi-layered nanosheets, which were formed by selective adsorption of ionic liquids on the Br-terminated surface, followed by the formation of hydrogen bond-co-π-π stacking.The synthesized BiOBr exhibited high activity, excellent stability, and superior mineralization ability in the photocatalytic degradation of organic dyes under visible light owing to its enhanced light absorbance and narrow bandgap. Furthermore, photo-generated electrons were determined to be the main active species by comparison with different trapping agents used in the photocatalytic reactions.
To study the temperature sensitivity of the destruction of organic compounds in supercritical water oxidation process （SCWO）, oxidation effects of twelve chemicals in supercritical water were investigated. The SCWO reaction rates of different compounds improved to varying degrees with the increase of temperature, so the highest slope of the temperature-effect curve （/max） was defined as the maximum ratio of removal ratio to working temperature. It is an important index to stand for the temperature sensitivity effect in SCWO. It was proven that the higher imax is, the more significant the effect of temperature on the SCWO effect is. Since the high-temperature area of SCWO equipment is subject to considerable damage from fatigue, the temperature is of great significance in SCWO equipment operation. Generally, most compounds （/max 〉 0.25） can be completely oxidized when the reactor temperature reaches 500~C. However, some compounds （/max 〉 0.25） need a higher temperature for complete oxidation, up to 560~C. To analyze the correlation coefficients between/max and various molecular descriptors, a quantum chemical method was used in this study. The structures of the twelve organic compounds were optimized by the Density Functional Theory B3LYP/6-311G method, as well as their quantum properties. It was shown that six molecular descriptors were negatively correlated to imax while other three descriptors were positively correlated to imax. Among them, dipole moment had the greatest effect on the oxidation thermodynamics of the twelve organic compounds. Once a correlation between molecular descriptors and imax is established, SCWO can be run at an appropriate temperature according to molecular structure.
Yaqin TanZhemin ShenWeimin GuoChuang OuyangJinping JiaWeili JiangHaiyun Zhou
