Capture of CO2 during the Electrolysis Process and Its Utilization in Supercapacitor Materials.

With climate change and environmental issues, the emissions of CO2 and its greenhouse effect have become a focal point. At present, the utilization of CO2 includes its synthesis into chemicals and fuels such as methane, methanol, and CO. CO2 utilization can be achieved through carbon capture and storage technologies, which involve capturing CO2 from industrial emissions and storing it to reduce the CO2 concentration in the atmosphere. However, these CO2 capture and utilization technologies still face challenges, such as technical immaturity and high costs. One of the CO2 capture and utilization technologies is the production of energy storage materials. In this study, CO2 captured by molten salt was used as the carbon source, and TiO2 nanotube arrays were used as precursors. Titanium carbide nanotube arrays(TiC-NTAs)with high specific surface area and high conductivity were prepared by electrolysis. Afterward, the electrochemical energy storage performance of TiC in different electrolytes was tested. The results show that reducing the ionic radius of the electrolyte is conducive to increasing the area-specific capacitance of the device and that the degradation of the cycle life of the quasi-solid supercapacitor may be caused by an increase in the internal resistance due to the loss of water from the electrolyte. This study provides a reference value for the low-temperature synthesis of nanometal carbides and the selection of electrolytes.

Interfacial Behavior and Dechlorination Reaction of Water Droplet Impact on a Heated Extracted Titanium Tailing Surface.

The interfacial behaviors of the droplet impact on a heated extracted titanium tailing surface are studied experimentally. The effects of surface temperatures and Weber numbers on the droplet spreading characteristics are examined. The factors affecting the mass fraction and dechlorination ratio of extracted titanium tailings under the action of interfacial behavior have been researched by thermogravimetric analysis. The compositions and microstructures of extracted titanium tailings are characterized using X-ray fluorescence spectroscopy and scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS). The interfacial behaviors on the extracted titanium tailing surface are classified into four regimes, i.e., boiling-induced break-up, advancing recoiling, splash with a continuous liquid film, and splash with a broken film. The maximum spreading factors increase with the surface temperature and the Weber number. It is found that the surface temperature has a dominant influence on the spreading factors and interfacial effect, further affecting its chlorination reaction. SEM-EDS analysis revealed that the extracted titanium tailing particles are irregular shaped. There are some fine pores on the surface after the reaction. The main concentrations are Si, Al, and Ca oxides with a certain amount of C elements. The findings of this research provide a new pathway to utilize the extracted titanium tailings comprehensively.

Prediction of Structural and Electronic Properties of C and Cl2 Adsorbed on the Rutile TiO2 (110) Surface.

The study of the adsorption mechanism of C and Cl2 on the TiO2 (110) surface is of great significance for the formulation of the technological parameters in the fluidized chlorination process. Based on the first-principles calculations of density functional theory, the co-adsorption models of C and Cl2 on the rutile TiO2 (110) surface under different ratios were established. The adsorption structure, adsorption energy, charge density, and density of states were calculated and analyzed to reveal the reaction mechanism of C and Cl2 adsorbed on the rutile TiO2 (110) surface under different ratios. The results showed that with the increase of the ratio of C atoms in the reaction process, the complete adsorption possibility of Cl atoms on the surface of TiO2 (110) increased. Both Ti6c and C atoms were electron providers, while O3c and O2c were electron acceptors. The bonding interactions between C and O2c or C and Cl atoms were stronger, and the stabilities were higher. When C bonded with O2c and two Cl atoms, respectively, the overlapping peak width of C and O2c atoms was greater at the high energy level, and the electron delocalization was enhanced, and more electrons were transferred around the two Cl atoms. When C bonded with O2c and one Cl atom, respectively, the electron activity at the low energy level was higher, and the stability of the chemical bond was lower.

Transformation of organic sulfur and its functional groups in nantong and laigang coal under microwave irradiation.

The microwave irradiation experiment of Nantong coal (NTC) and Laigang coal (LGC) has been carried out in a microwave oven and the transformation of organic sulfur and its functional groups was investigated via compact sulfur tester and Fourier transform infrared spectra. The dielectric properties of coal sample are also measured by an Agilent N5244A network analyzer. The result shows that a certain amount of organic sulfur in both NTC and LGC is transformed into iron sulfide, sulfate, and sulfur-containing gas after irradiation of microwave. The retention proportion of the three typical sulfur-containing functional groups in coal is ranking as: disulfide bond (S-S) > sulfinyl (SO) > sulfydryl (-SH), and such phenomenon has been explained by the first principle calculation based on the density functional theory. The calculation results of Fukui indices, electrostatic potential, and frontier orbital analysis indicate the reactivity of the SO and SS is lower than that of the -SH. The calculated bond dissociation enthalpies and bond dissociation times indicate the chemical bonds of -SH and S-S need more time to rupture than SO when microwave power is 1000 W. © 2019 Wiley Periodicals, Inc.

Effects of poplar addition on tar formation during the co-pyrolysis of fat coal and poplar at high temperature.

Three-stage absorption by butyl acetate was used to obtain tar components during the co-pyrolysis of fat coal and poplar at high temperature. The resulting tar yields were calculated relative to the fat coal and poplar blends. The tar components were characterized by gas chromatography-mass spectrometry, Fourier transform-infrared spectroscopy and 1H nuclear magnetic resonance spectroscopy. The effects of the added poplar on tar formation were then considered. The results show that the poplar-fat coal tar yield rose slightly when the poplar addition levels ranged from 4% to 12% and then increased much more at higher poplar addition levels. Oxygenated and aromatic compounds contributed greatly to the poplar-fat coal tar yield. The quantity of oxygenated components increased in the poplar blending ratio range from 4% to 12% and decreased as the ratio increased further, while the quantity of aromatic components showed the opposite trend. The influences of poplar addition levels on tar formation could be divided into two stages: (a) lighten the tar by stabilizing radicals at low poplar addition levels; (b) form heavier tar due to cross-linking reactions of the remaining radicals at high poplar addition levels. When the poplar addition levels ranged from 4% to 12%, due to synergistic effects, large amounts of free radicals and hydrogen from the co-pyrolysis of coal and poplar formed lighter stable compounds, which were then transported into the tar. Further, cross-linking reactions could be decreased because fewer free radicals and less hydrogen remained. As a result, the amount of PAHs declined, the tar yield rose slightly, the hydrocarbon-generating potential improved, the aliphatic chain length shortened, and the aromatic protons decreased. At higher blending ratios, excess radicals existed after stabilization due to the increasing poplar addition levels. These radicals underwent cross-linking reactions and produced PAHs, resulting in heavily increased tar yields, weakened hydrocarbon-generating potential, extended aliphatic chain lengths and increased aromatic protons.