十二烷基吗啉选择性吸附氯化钠的分子模拟

采用分子模拟方法研究氯化钠-光卤石反浮选体系中捕收剂十二烷基吗啉(DMP)选择性吸附氯化钠的机理. 用Material Studio 4.0软件和COMPASS分子力场方法建立了DMP在氯化钠和光卤石两种矿物表面的吸附模型, 并进行动力学模拟和能量优化, 确立了DMP在两种矿物表面的最佳吸附构型. 结果表明, DMP分子通过其官能团中的O、N原子与氯化钠界面水结构中的H原子之间的氢键作用吸附在氯化钠表面, 吸附作用能为-119.49 kJ·mol-1, 而光卤石界面水结构不能保持稳定排列, 致使DMP直接作用在光卤石表面, 吸附能为-37.97 kJ·mol-1, 在两种矿物共存体系中, 这种吸附能差异导致了DMP在氯化钠表面的选择性吸附.

Molecular Modeling for Selective Adsorption of Halite with Dodecylmorpholine

Molecular modeling techniques were employed to investigate the selective adsorption mechanism of NaCl with collector dodecylmorpholine(DMP) in halite-carnallite reverse flotation system. Adsorption models of DMP on halite and carnallite surfaces were constructed and optimized using Material Studio 4.0 program and COMPASS force field method, molecular dynamics simulation and minimization method were used to search the most favorable adsorption models.We conclude that DMP adsorbs on the interfacial water structure of halite (100) surface by hydrogen bonding between the oxygen and nitrogen atoms in the functional group of DMP and hydrogen atoms in the water structure. The interaction energy between them was found to be -119.49 kJ·mol-1. The structure of water on carnallite surface is not stable, which allows DMP direct contact with carnallite surface at a smaller adsorption energy of -37.97 kJ·mol -1. Because of the difference in adsorption energies of DMP with the two minerals, we assumed that DMP preferentially adsorbs on halite surface in the flotation process.