摘要
为了研究酸化前后煤样化学结构及其吸附性能的变化特性,采用氢氟酸酸化处理贵州无烟煤,运用X射线衍射仪(XRD)测定煤样无机矿物质含量及大分子结构基本单元的变化特征;利用傅里叶变换红外光谱(FTIR)剖析煤样官能团含量及其聚合程度的变化机制;基于量子化学理论,采用Gaussian 9软件模拟分析含氧官能团和烷基侧链对煤吸附瓦斯的影响,从分子水平探究瓦斯在煤表面的吸附机理。结果表明:酸化能消除煤样内部矿物质,并改变其微晶结构参数;酸化处理后,煤样表面含氧官能团增多,甲基与亚甲基等烷基侧链减少,且芳香结构及脂肪结构参数均变小;在所构建的7个煤分子吸附瓦斯模型中,吸附能最大的为亚甲基吸附模型,其次为甲基吸附模型,而醛基、醚氧基、羧基及羟基的吸附能绝对值均小于单个苯环的吸附模型。
To study the change characteristics of the chemical structure and adsorption performance of coal samples before and after acidification, hydrofluoric acid was used to acidify Guizhou anthracite. X-ray diffraction(XRD) was used to determine the change rules of inorganic mineral content and basic units of the macromolecular structure in coal samples. Fourier transform infrared spectroscopy(FTIR) was used to analyze the change mechanism of functional group content and polymerization degree in coal samples. Based on quantum chemistry theory, Gaussian 9 software was used to simulate and analyze the influence of oxygen-containing functional groups and alkyl side chains on the gas adsorption on coal surfaces. The adsorption mechanism of gas on coal surfaces was explored from the molecular level. The research results show that acidification can remove inorganic minerals from coal and improve the purity of organic matter, and increase the net spacing by 1.8%. Besides, the unit stacking height and unit extension of aromatic lamellae decrease by about 21.3%, which indicates that acidification can reduce the aromatic core of coal molecules, depolymerize its chemical structure, improve pore connectivity and promote gas desorption. After acidification treatment, the oxygen-containing functional groups on the coal surface increase, the alkyl side chains such as methyl and methylene decrease greatly, and the polycondensation degree, fatty chain length, and branching degree of aromatic rings in the coal sample decrease. It indicates that acidification can reduce the polymerization degree between functional groups, loosen their molecular structure, and weaken the adsorption capacity of coal surface to gas. In the seven models of gas adsorption of coal molecules, the largest adsorption energy is the methylene adsorption model, followed by the methyl adsorption model. The absolute value of adsorption energy of aldehyde group, etheroxy group, carboxyl group and hydroxyl group is less than that of the single benzene ring adsorption model.
作者
袁梅
陈恋
吕晴
董洪
韦善阳
许石青
YUAN Mei;CHEN Lian;Lü Qing;DONG Hong;WEI Shan-yang;XU Shi-qing(Mining College,Guizhou University,Guiyang 550025,China;Key Laboratory of Karst Geological Resources and Environment,Ministry of Education,Guiyang 550025,China;Guizhou Linhua Mining Company,Liupanshui 553000,Guizhou,China)
出处
《安全与环境学报》
CAS
CSCD
北大核心
2022年第1期132-141,共10页
Journal of Safety and Environment
基金
国家自然科学基金项目(52164014)
贵州省科技支撑计划项目(黔科合支撑[2017]2815,黔科合支撑[2019]2887)。
关键词
安全工程
酸化
无烟煤
分子结构
官能团
吸附性能
safety engineering
acidification
anthracite
molecular structure
functional group
adsorption performance
