SDS对烟煤润湿性能和机理的分子模拟研究*

为探究十二烷基硫酸钠（SDS）对烟煤的润湿机理，首先通过实验分析SDS对烟煤润湿性能影响，然后利用分子模拟对SDS在烟煤表面的润湿过程进行研究。研究结果表明:SDS溶液改善烟煤的润湿性能，全尘、呼吸性粉尘降尘效率分别比纯水提高7.95%和10%；根据轨道能级差和静电势分析得出，SDS分子尾链吸附烟煤表面、头基朝向水中的吸附构型降低水和烟煤的液-固界面张力；SDS分子覆盖烟煤表面后，系统中烟煤与水分子的非键作用能、氢键数量、水分子的起始位点分别由-1 114.91 kcal/mol，1 810个，1.59 变为-3 405.68 kcal/mol，1 996个，1.57 ，在SDS分子的作用下烟煤表面与水分子结合能力变强，大量水分子通过氢键作用凝聚在头基附近，水分子整体移向烟煤使烟煤表面得到充分的浸润和渗透。研究结果可为新型表面活性剂润湿煤尘性能检验提供参考。

Molecular simulation study on wettability performance and mechanism of SDS on bituminous coal

To investigate the wettability mechanism of sodium dodecyl sulfate (SDS) on bituminous coal,the influence of SDS on the wettability performance of bituminous coal was analyzed experimentally,and the wettability process of SDS on the surface of bituminous coal was investigated by using molecular simulation.The results showed that the SDS solution improved the wettability performance of bituminous coal,and the dust reduction efficiency of whole dust and respirable dust increased by 7.95% and 10%,respectively,compared with pure water.Based on the analysis of orbital energy level difference and electrostatic potential,it was concluded that the adsorption configuration of SDS molecule tail chain adsorbed on the surface of bituminous coal and head group toward water reduced the liquid-solid interfacial tension of water and bituminous coal.After SDS molecules covered the surface of bituminous coal,the non-bonding energy,the number of hydrogen bonds,and the initiation site of water molecules with bituminous coal in the system changed from -1 114.91 kcal/mol,1 810,and 1.59  to -3 405.68 kcal/mol,1996,and 1.57 ,respectively,and the binding ability of bituminous coal surface with water molecules became stronger under the action of SDS molecules.A large number of water molecules coalesced near the head group through the hydrogen bonding,so that the water molecules moved to the surface of bituminous coal as a whole and the bituminous coal was fully infiltrated and penetrated.The research results can provide reference for the performance test of new surfactant wetting coal dust in the future.