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Abstract：
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.
摘要：
研究表面活性剂对Wiser烟煤可浮性的影响对提高煤的洁净度和利用价值具有重要意义。利用密度泛函理论和分子动力学模拟方法,本研究构建了Wiser烟煤模型，并研究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乙氧基化醚。重点研究了这些分子的电荷分布特性以及二元表面活性剂对烟煤疏水性的改性作用。结果表明，最大的静电势集中在氧/氮/含硫官能团附近，如磺酸基团，季铵阳离子，环氧乙烷,羟基，羧基,和硫键。这些官能团表现出接受/递送电子以形成氢键的倾向。在测试的表面活性剂中，CTAB揭示了前沿轨道能量的微小差异，测量3.187eV，从而证明了与其它两种表面活性剂相比优异的捕获能力。确定系统内的吸附反应是自发的，超过60%的相互作用力归因于静电力。此外，与水分子的斥力大小遵循以下趋势:磺酸盐基团(2.20)<环氧乙烷(2.43)<季铵阳离子(2.57)，表明CTAB具有更优异的防水性。研究结果表明，CTAE二元表面活性剂被证明对改善烟煤的疏水性最有效。这项研究提供了减少浪费的宝贵见解，污染,和资源浪费。
