CIESC Journal ›› 2023, Vol. 74 ›› Issue (9): 3931-3945.DOI: 10.11949/0438-1157.20230557

• Energy and environmental engineering • Previous Articles     Next Articles

Microscopic mechanism of SiO2-H2O nanofluids to enhance the wettability of coal dust

Jiajia ZHAO1(), Shixiang TIAN1,2(), Peng LI3, Honggao XIE1   

  1. 1.College of Mining, Guizhou University, Guiyang 550025, Guizhou,China
    2.Guizhou Engineering Center for Safe Mining Technology, Guiyang 550025, Guizhou,China
    3.CCTEG Shenyang Research Institute, Fushun 113122, Liaoning,China
  • Received:2023-06-09 Revised:2023-09-02 Online:2023-11-20 Published:2023-09-25
  • Contact: Shixiang TIAN

SiO2-H2O纳米流体强化煤尘润湿性的微观机理研究

赵佳佳1(), 田世祥1,2(), 李鹏3, 谢洪高1   

  1. 1.贵州大学矿业学院,贵州 贵阳 550025
    2.贵州省复杂地质矿山开采安全技术工程中心,贵州 贵阳 550025
    3.中煤科工集团沈阳研究院有限公司,辽宁 抚顺 113122
  • 通讯作者: 田世祥
  • 作者简介:赵佳佳(1998—),男,硕士研究生,1845628454@qq.com
  • 基金资助:
    国家自然科学基金项目(52104079);贵州省省级科技计划项目(黔科合支撑[2020]4Y050)

Abstract:

Coal dust pollution is one of the problems that the world’s coal industry needs to solve urgently. Exploring green and efficient new coal dust wetting agents has potential application value in this field. In this study, the mechanism of the effect of SiO2-H2O nanofluid on the wettability of coal dust was investigated by the Wender model using Materials Studio molecular simulation software and physical experiments. The results show that the reactivity of SiO2 nanoparticles (NPs) is high, and their surface hydroxyl groups can easily form hydrogen bonds with coal molecules and water molecules, thus affecting the wetting properties of coal dust. NPs have a strong ability to interact with coal molecules, and their adsorption on the surface of coal dust can adsorb more water molecules. When the adsorption number of NPs was 0—5, the interaction energies between coal and NPs, NPs and water, and the number of hydrogen bonds between solid-liquid molecules in the adsorption system tended to increase with the increase in the number of NPs. The g(r) curves between hydrogen and oxygen atoms in coal and NPs have the largest values and higher peaks, while the g(r) curves between hydrogen and oxygen atoms in coal and water are the opposite. With the increase of the adsorbed number of NPs, the water molecule mean square displacement and diffusion coefficient tended to increase, which accelerated the wetting of coal dust. Compared with water, the nanofluids have lower surface tension, and when the particle concentration is 2.0%(mass), the decrease rate of contact angle of modified coal dust reaches about 52.85%—61.51%, while the adsorption and agglomeration of NPs on the surface of nanofluid-treated coal dust is obvious. In this study, the molecular simulation results were verified with the experimental results, which elucidated the microscopic mechanism of NPs to enhance the wettability of coal dust, obtained the influence law of NPs on the wettability of coal dust, revealed the adsorption characteristics of NPs on the surface of coal dust, and laid a theoretical foundation for the enhancement of the wettability of coal dust by SiO2-H2O nanofluids.

Key words: SiO2-H2O nanofluids, coal dust, wettability, molecular simulation

摘要:

煤尘污染是世界煤炭行业亟需解决的难题之一,探索绿色高效的新型煤尘润湿剂对于该领域来说具有潜在的应用价值。以Wender模型为研究对象,借助Materials Studio分子模拟软件与物理实验探究了SiO2-H2O纳米流体对煤尘润湿性的影响机制。研究表明:SiO2纳米颗粒(NPs)的反应活性较高,其表面羟基容易与煤分子和水分子形成氢键,从而影响煤尘的润湿特性。NPs与煤分子的相互作用能力较强,其吸附在煤尘表面后能吸附更多的水分子。当体系中NPs的吸附数量为0~5时,随NPs数量的增加,吸附体系中煤和NPs、NPs和水之间的相互作用能以及固-液分子间氢键的数量呈增大的趋势。煤和NPs中氢、氧原子之间的g(r)曲线值最大,峰值较高,而煤和水中氢、氧原子之间的g(r)曲线与之相反。随着NPs吸附数量的增加,水分子均方位移与扩散系数呈增大的趋势,加速了对煤尘的润湿。与水相比,纳米流体具有较低的表面张力,当颗粒浓度为2.0%(质量)时,改性煤尘接触角下降率达到了52.85%~61.51%,同时纳米流体处理后的煤尘表面NPs吸附集聚现象明显。本研究分子模拟结果与实验结果相互验证,阐明了NPs强化煤尘润湿性的微观机理,获得了NPs对煤尘润湿性的影响规律,揭示了NPs在煤尘表面的吸附特征,为SiO2-H2O纳米流体强化煤尘润湿性奠定了理论基础。

关键词: SiO2-H2O纳米流体, 煤尘, 润湿性, 分子模拟

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