Zhang Chun, Qian Xianju, Song Hailong, Jia Jinzhang
College of Safety Science and Engineering, Liaoning Technical University, Fuxin, 123000, Liaoning, China.
Key Laboratory of Thermal Dynamic Disaster Prevention and Control of Ministry of Education, Liaoning Technical University, Huludao, 125105, Liaoning, China.
Sci Rep. 2024 Jun 24;14(1):14495. doi: 10.1038/s41598-024-65466-7.
Investigating surfactant effects on the floatability of Wiser bituminous coal holds significant importance in improving coal cleanliness and utilization value. Using density functional theory and molecular dynamics simulation methods, this study constructed models of Wiser bituminous coal and examined the impact of different surfactants, including the anionic surfactant sodium dodecyl benzene sulfonate, the cationic surfactant hexadecyl trimethyl ammonium bromide (CTAB), and the non-ionic surfactant fatty alcohol ethoxylated ether. The focus was on investigating the charge distribution characteristics of these molecules and the modifying effect of binary surfactants on the hydrophobicity of bituminous coal. Results revealed that the maximum electrostatic potential was concentrated near oxygen/nitrogen/sulfur-containing functional groups like sulfonic acid groups, quaternary ammonium cations, ethylene oxide, hydroxyl groups, carboxyl groups, and sulfur bonds. These functional groups exhibited a propensity for accepting/delivering electrons to form hydrogen bonds. Among the surfactants tested, CTAB revealed the slightest difference in frontier orbital energy, measuring 3.187 eV, thereby demonstrating a superior trapping ability compared with the other two surfactants. Adsorption reactions within the system were determined to be spontaneous, with over 60% of the interaction force attributed to electrostatic forces. Moreover, the repulsive force magnitude with water molecules followed the trend: sulfonate group (2.20 Å) < ethylene oxide (2.43 Å) < quaternary ammonium cation (2.57 Å), indicating more excellent water repellency of CTAB. Findings showed that CTAE binary surfactants proved most effective in modifying the hydrophobicity of bituminous coal. This study offers valuable insights into reducing waste, pollution, and resource wastage.
研究表面活性剂对怀泽烟煤可浮性的影响对于提高煤炭清洁度和利用价值具有重要意义。本研究采用密度泛函理论和分子动力学模拟方法，构建了怀泽烟煤模型，并考察了不同表面活性剂的影响，包括阴离子表面活性剂十二烷基苯磺酸钠、阳离子表面活性剂十六烷基三甲基溴化铵（CTAB）和非离子表面活性剂脂肪醇聚氧乙烯醚。重点研究了这些分子的电荷分布特征以及二元表面活性剂对烟煤疏水性的改性作用。结果表明，最大静电势集中在磺酸基、季铵阳离子、环氧乙烷、羟基、羧基和硫键等含氮/氧/硫官能团附近。这些官能团具有接受/传递电子以形成氢键的倾向。在所测试的表面活性剂中，CTAB的前线轨道能量差异最小，为3.187 eV，因此与其他两种表面活性剂相比具有更强的捕获能力。系统内的吸附反应被确定为自发反应，超过60%的相互作用力归因于静电力。此外，与水分子的排斥力大小顺序为：磺酸根基团（2.20 Å）＜环氧乙烷（2.43 Å）＜季铵阳离子（2.57 Å），表明CTAB具有更优异的疏水性。研究结果表明，CTAE二元表面活性剂在改变烟煤疏水性方面最为有效。本研究为减少废物、污染和资源浪费提供了有价值的见解。
