Oxidation of coal under mild conditions is effective not only to understand the macromolecular network structure of coal but also to produce useful chemicals, allowing more efficient application of coal resources. In this work, the mild oxidation of Zhundong subbituminous coal (ZS) by Fe 2+ /H 2 O 2 system was carried out under various conditions, including [Fe 2+ ]/[H 2 O 2 ] molar ratio, temperature, H 2 O 2 concentration and oxidation time. The liquid oxidation products were analyzed using gas chromatography/mass spectrometry (GC/MS), and the chemical structure changes were studied using Fourier transform infrared spectroscopy (FTIR). The results suggest that the oxidation efficiency of ZS with H 2 O 2 is enhanced with the aid of Fe 2+ . The optimum conditions were determined to be [Fe 2+ ]/[H 2 O 2 ] molar ratio of 0.00453, H 2 O 2 concentration of 3mol/L, 60 oC and 4 h according to the oxidation conversion rate. In total, 25 compounds were identified, which could be categorized as six group components. Most of them are valuedadded chemicals, and the content of benzene carboxylic acids is the highest among them, making up 29.99% of all group components in total relative content (TRC). -CH 2 - should be primary bridge connecting the aromatic rings, and alkylene chains linking three aromatic rings are abundant in ZS.
The precise separation of macerals is the premise and foundation for the efficient utilization of coal resources, and flotation is the separation method with the greatest industrial potential. The differences in the surface hydrophobicity of macerals provide the basis for flotation, but the complexity of their surface properties makes separation challenging. In this study, sub-bituminous coal was used to obtain vitrinite and inertinite , and a detailed analysis was carried out on the samples. The surface morphologies of vitrinite and inertinite were observed in the QI TM (quantitative imaging) mode of AFM (atomic force microscope) to explore the adsorption of the reagents. The effect of the reagents on the interaction forces between the coal particles and bubbles was measured to reveal the change in hydrophobicity. The attachment performance of macerals under different reagent treatments was investigated using a laboratory-built apparatus. Overall, the results demonstrated that the difference in zeta potential between vitrinite and inertinite was a viable approach for separating the macerals. CTAB adsorption on coal samples changed the surface morphology and the interaction force between particles and bubbles. Interestingly, CTAB adsorption on the gas–liquid interface decreased the interaction force. Vitrinite and inertinite attachment performances were enhanced when Al 3+ and SDS were used simultaneously.