煤基活性炭改性及其甲烷吸附能力

针对无烟煤制备成的煤基活性炭，采用酸式改性、碱式改性和联合改性的方法对其进行改性处理。通过低温液氮吸附实验、傅里叶红外光谱技术、高压甲烷吸附实验，分析了煤基活性炭的表面物理、化学结构、甲烷的吸附能力。借助Langmuir吸附等温模型、Freundlich模型进行数据拟合，研究了吸附热力学和动力学特征。结果表明，联合改性后的煤基活性炭比表面积和孔容均明显增大，其中比表面积增大66.66%，总孔容增大30.89%；煤基活性炭的甲烷吸附能力明显提高，甲烷吸附量提升25.686%。煤基活性炭的孔隙结构和表面官能团共同决定了其对甲烷的吸附作用，且较于孔隙结构，表面官能团的极性对甲烷吸附量起主要作用。 

Characteristic modification of coal-based activated carbon and its methane adsorption capacity

Methane is an important high-quality clean energy that mainly comes from the decomposition of organic waste, natural gas, fossil fuel extracts, etc. Recycling it from a gaseous mixture is beneficial for environmental protection and energy utilization and development. The new coal-based activated carbon is a widely used storage material for methane because of its economic benefit and practicality; thus, coal-based activated carbon modification is greatly significant. This research aims to further reveal the methane adsorption mechanism of coal-based activated carbon by studying the influence of acidic, basic, and combined modifications on methane adsorption and seek a more efficient means of coal-based activated carbon modification. The coal-based activated carbon made from anthracite coal was processed through acidic, basic, and combined modifications. In addition, the physical and chemical structures of the coal-based activated carbon surface and the adsorption ability of methane were precisely analyzed through low-temperature liquid nitrogen adsorption, Fourier infrared spectroscopy, and high-pressure methane adsorption experiments. The characteristics of adsorption thermodynamics and kinetics were also determined by using the Langmuir adsorption isotherm model and the Freundlich model for data fitting. The results show a significant increase in the specific surface area and pore volume of the coal-based activated carbon after combined modification. The specific surface area and the total pore volume increases by 66.66% and 30.89%, respectively. The methane adsorption capacity of the coal-based activated carbon also significantly improved after combined modification. Methane adsorption increases by 25.686%. In addition, both the pore structure and the contained functional groups on the surface jointly determine the methane adsorption, which is mainly affected by the polarity of the surface functional groups rather than the pore structure.