A novel chromone Schiff base as Zn2+ turn-on fluorescent chemosensor in a mixed solution.

In this study, a novel fluorescent chemosensor 1 based on chromone-3-carboxaldehyde Schiff base was synthesized and featured through nuclear magnetic resonance (NMR) and mass spectra. Spectroscopic investigation indicated that the fluorescent sensor showed high selectivity toward Zn2+ over other metal ions and that the detection limit of 1 could reach 10-7  M. These indicated that 1 acted as a highly selective and sensitive fluorescence chemosensor for Zn2+ .

Immobilization of chromium in real tannery sludge via heat treatment with coal fly ash.

The secure and harmless disposal for Cr-bearing tannery sludge (Cr-TS) has attracted an increasing concern, due to potentially adverse effect on ecosystem and human health. A greener alternative method about "waste treatment with waste" for thermally stabilizing real Cr-TS was developed via employing coal fly ash (CA) as dopants in this research. The co-heat treatment of Cr-TS and CA was carried out at the temperature range of 600-1200 °C to investigate the oxidation of Cr(III), immobilization of chromium and leaching risk of the sintered products, and the mechanism of chromium immobilization was further explored. The results indicate that the doping of CA can significantly inhibit the oxidation of Cr(III) and immobilize chromium by incorporating chromium into spinel and uvarovite microcrystal. At the temperature higher than 1000 °C, most of chromium can be converted into stable crystalline phases. Furthermore, a prolonged leaching test was conducted to study the leaching toxicity of chromium in sintered products, indicating that leaching content of chromium is much less than the regulatory limit. This process is a feasible and promising alternative for immobilization of chromium in Cr-TS. The research findings are supposed to offer a theoretical foundation and strategy choice for thermal stabilization of chromium, as well as safety and harmless disposal of Cr-containing hazardous waste.

Preparation of diameter-controlled free-standing MWCNT membranes and their application for dye adsorption.

The synthesis of multi-walled carbon nanotubes (MWCNTs) was carried out over different Ni-loaded metallic oxide catalyst nanoparticles and under different reduction times to control the outside diameter of the nanotubes. Moreover, high-purity, free-standing membranes were fabricated by a simple filtration of the as-grown MWCNTs. Furthermore, the dye-adsorption properties of the nanotubes depended on the diameter of the carbon nanotubes (CNTs). The adsorption isotherms and kinetics of anionic dyes could be described by Freundlich and pseudo-second-order models, respectively. Thermodynamic studies suggested that the adsorption processes were spontaneous and exothermic. This work provides new insights into the synthesis and application of MWCNTs with the selective adsorption properties of carbon-based materials for the removal of organic dyes.

Crystal structure, thermal properties and detonation characterization of bis(5-amino-1,2,4-triazol-4-ium-3-yl)methane dinitrate.

Bis(5-amino-1,2,4-triazol-4-ium-3-yl)methane dinitrate, BATZM·(NO3)2 or C5H10N82+·2NO3-, was synthesized and its crystal structure determined by single-crystal X-ray diffraction. It crystallizes in the space group Pbcn (orthorhombic) with Z = 4. BATZM·(NO3)2 is a V-shaped molecule where hydrogen bonds form a two-dimensional corrugated sheet with reasonable chemical geometry and no disorder. The specific molar heat capacity (Cp,m) of BATZM·(NO3)2 was determined using the continuous Cp mode of a microcalorimeter and theoretical calculations, and the Cp,m value is 366.14 J K-1 mol-1 at 298.15 K. The relative deviations between the theoretical and experimental values of Cp,m, HT - H298.15K and ST - S298.15K of BATZM·(NO3)2 are almost equivalent at each temperature. The detonation velocity (D) and detonation pressure (P) were estimated using the nitrogen equivalent equation according to the experimental density; BATZM·(NO3)2 has a higher detonation velocity (7927.47 ±â€…3.63 m s-1) and detonation pressure (27.50 ±â€…0.03 GPa) than 2,4,6-trinitrotoluene (TNT). The above results for BATZM·(NO3)2 are compared with those of bis(5-amino-1,2,4-triazol-3-yl)methane (BATZM) and bis(5-amino-1,2,4-triazol-4-ium-3-yl)methane dihydrochloride (BATZM·Cl2), and the effect of nitrate formation is discussed.

Crystal structure, thermal behaviour and detonation characterization of bis(4,5-diamino-1,2,4-triazol-3-yl)methane monohydrate.

Bis(4,5-diamino-1,2,4-triazol-3-yl)methane monohydrate (BDATZM·H2O or C5H10N10·H2O) was synthesized and its crystal structure characterized by single-crystal X-ray diffraction; it belongs to the space group P-1 (triclinic) with Z = 2. The structure of BDATZM·H2O can be described as a two-dimensional ladder plane with extensive hydrogen bonding and no disorder. The thermal behaviour was studied under non-isothermal conditions by differential scanning calorimetry (DSC) and thermogravimetric/differential thermogravimetric (TG/DTG) methods. The detonation velocity (D) and detonation pressure (P) of BDATZM were estimated using the nitrogen equivalent equation according to the experimental density. A comparison between BDATZM·H2O and bis(5-amino-1,2,4-triazol-3-yl)methane (BATZM) was made to determine the effect of the amino group; the results suggest that the amino group increases the hydrophilicity, space utilization and energy, and decreases the thermal stability and symmetry of the resulting compound.

Crystal structure, thermal properties and detonation characterization of bis(5-amino-1,2,4-triazol-4-ium-3-yl)methane dichloride.

Bis(5-amino-1,2,4-triazol-4-ium-3-yl)methane dichloride (BATZM·Cl2 or C5H10N82+·2Cl-) was synthesized and crystallized, and the crystal structure was characterized by single-crystal X-ray diffraction; it belongs to the space group C2/c (monoclinic) with Z = 4. The structure of BATZM·Cl2 can be described as a V-shaped molecule with reasonable chemical geometry and no disorder, and its one-dimensional structure can be described as a rhombic helix. The specific molar heat capacity (Cp,m) of BATZM·Cl2 was determined using the continuous Cp mode of a microcalorimeter and theoretical calculations, and the Cp,m value is 276.18 J K-1 mol-1 at 298.15 K. The relative deviations between the theoretical and experimental values of Cp,m, HT - H298.15K and ST - S298.15K of BATZM·Cl2 are almost equivalent at each temperature. The detonation velocity (D) and detonation pressure (P) of BATZM·Cl2 were estimated using the nitrogen equivalent equation according to the experimental density; BATZM·Cl2 has a higher detonation velocity (7143.60 ±â€…3.66 m s-1) and detonation pressure (21.49 ±â€…0.03 GPa) than TNT. The above results for BATZM·Cl2 are compared with those of bis(5-amino-1,2,4-triazol-3-yl)methane (BATZM) and the effect of salt formation on them is discussed.

Did carbon dioxide emission regulations inhibit investments? A provincial panel analysis of China.

Investments, especially fixed asset investments, greatly affect carbon dioxide (CO2) emissions. When investments are concentrated in regions with high CO2 emissions and high fossil energy consumption, the CO2 emission reduction targets in these areas are difficult to reach in the short term, and the cost of CO2 emission abatement is high. The current CO2 emission regulations focus on existing production activities and consumption behaviors. However, whether an investment, which may affect CO2 emissions in the long term, is effectively inhibited by CO2 emission regulations has not been investigated in previous studies. Using panel data from 30 provinces in China between 2003 and 2012, we tested whether the amount of provincial investment was constrained or promoted by the provincial CO2 emission regulations by creating a panel model with provincial samples. The results revealed that CO2 emission regulations did not inhibit the growth of an investment, but they stimulated investments to varying degrees in different provinces. A relatively positive result is that provinces with stronger CO2 emission regulations exhibited a relatively small contribution to investment promotion, while provinces with weaker CO2 reduction policies demonstrated a relatively large contribution to investment growth. We also found that investment was correlated with the growth rate of the gross domestic product (GDP) in the northeastern and western provinces. Finally, we proposed policy implications based on the utilization of policy tools from the perspectives of investment, energy structure, and local protectionism.