Huan Xuan, Guo Xiaojie, Chen Xuexi, Guo Xin
Institute of Disaster Prevention Science and Safety Technology, No. 465, Xueyuan Street, Yanjiao High-tech Zone, Sanhe, Hebei 065201, P. R. China.
North China Institute of Science and Technology, No. 467, Xueyuan Street, Yanjiao High-tech Zone, Sanhe, Hebei 065201, P. R. China.
ACS Omega. 2024 Jul 24;9(31):33510-33521. doi: 10.1021/acsomega.4c00978. eCollection 2024 Aug 6.
A series of coal-based activated carbons (CACs) were synthesized from mylonitized fat coal, a type of tectonically deformed coal (TDC) and symbiotic primary structural coal (PSC), followed by oxidative modification. The pore structure, surface oxygen-containing functional groups, and their influence on methane adsorption by CAC as the simplified coal model were investigated by using low-temperature nitrogen adsorption, Fourier transform infrared spectroscopy, Boehm titration, and X-ray photoelectron spectroscopy. The results showed that tectonic deformation fostered smaller pores, particularly ultramicropores in TDC, dominating methane adsorption. Acid-modified TDC-based activated carbons (ACs) showed higher pore parameters and oxygen-containing functional groups than those of PSC-based ACs. Nitric acid introduced abundant carboxyl groups concurrently increasing the pore volume and specific surface area (SSA), while sulfuric acid-ammonium persulfate treatment resulted in increased lactone groups and a partial collapse/blockage of nanopores. Methane adsorption experiments confirmed the importance of micropores and revealed a significant decrease in capacity owing to increased oxygen-containing functional groups as the primary role, with pore wall corrosion playing a secondary role. Thus, the study highlights the surface effects of TDC on methane adsorption and the potential for producing high-performance methane storage materials from China's tectonic coal resources.
以糜棱化肥煤（一种构造变形煤（TDC））和共生原生结构煤（PSC）为原料，合成了一系列煤基活性炭（CAC），并进行了氧化改性。采用低温氮吸附、傅里叶变换红外光谱、 Boehm滴定和X射线光电子能谱等方法，研究了CAC作为简化煤模型的孔隙结构、表面含氧官能团及其对甲烷吸附的影响。结果表明，构造变形促进了更小孔隙的形成，特别是TDC中的超微孔，主导了甲烷吸附。酸改性的基于TDC的活性炭（AC）比基于PSC的AC具有更高的孔隙参数和含氧官能团。硝酸引入了丰富的羧基，同时增加了孔容和比表面积（SSA），而硫酸-过硫酸铵处理导致内酯基团增加和纳米孔部分塌陷/堵塞。甲烷吸附实验证实了微孔的重要性，并揭示了由于含氧官能团增加作为主要作用导致容量显著下降，孔壁腐蚀起次要作用。因此，该研究突出了TDC对甲烷吸附的表面效应以及利用中国构造煤资源生产高性能甲烷储存材料的潜力。
