ABSTRACT

Lignite is easily oxidized, and spontaneous combustion occurs during its storage, which greatly reduces its calorific value and affects its quality and economic benefits. The surface properties of the oxidized lignite including pore structure and oxygen-containing functional groups were investigated by N₂ adsorption/desorption isotherms and Fourier transform infrared spectroscopy. The adsorption of Congo red dye in aqueous solution by oxidized lignite was carried out. It was observed that due to oxidation, the specific surface area and total pore volume of the Huolinhe lignite samples decreased, and the average pore size increased. As oxidation temperature increased, the number of microporous and mesoporous structures decreased, resulting in the decrease of fractal dimension. The hydroxyl content was negatively correlated with the oxidation temperature, but the carbonyl content showed an opposite trend. At the initial stage of oxidation, the rate of hydroxyl consumption is higher than that of formation. The reaction to generate carbonyl, such as the oxidation of aliphatic hydrocarbons, alcohol hydroxyl groups and ethers, requires a higher reaction temperature, so the carbonyl content increased when the temperature was higher than 70 °C. Oxidized lignite was used to adsorb Congo red dye in aqueous solution, and the removal increased significantly with increasing oxidation temperature. Therefore, oxidized lignite can effectively remove Congo red dye from aqueous solution, so as to improve the economic benefit of oxidized lignite.

摘要

褐煤易氧化，在贮存过程中发生自燃，使其热值大大降低，影响质量和经济效益。_{通过N 2}研究了氧化褐煤的表面性质，包括孔结构和含氧官能团吸附/脱附等温线和傅里叶变换红外光谱。进行了氧化褐煤对水溶液中刚果红染料的吸附。据观察，由于氧化作用，霍林河褐煤样品的比表面积和总孔容降低，平均孔径增大。随着氧化温度升高，微孔和中孔结构的数量减少，导致分形维数降低。羟基含量与氧化温度呈负相关，但羰基含量呈相反趋势。在氧化初期，羟基消耗的速率高于生成的速率。生成羰基的反应，如脂肪烃、醇羟基和醚的氧化，要求较高的反应温度，因此当温度高于70℃时羰基含量增加。氧化褐煤用于吸附水溶液中的刚果红染料，随着氧化温度的升高，去除率显着增加。因此，氧化褐煤可以有效去除水溶液中的刚果红染料，从而提高氧化褐煤的经济效益。