Molecular dynamic simulations of polyacrylic acid polyelectrolyte (PAA) analyzed its interaction with the main minerals that make up characteristic tailings of the mining industry, in this case, quartz, kaolinite, and montmorillonite. The simulations were carried out with the package Gromacs 2020.3. The interaction potentials used were General AMBER Force Field (GAFF) for PAA and CLAYFF-MOH for mineral surfaces. The SPC/E model described water molecules and Lennard-Jones 12-6 parameters adjusted for SPC/E model were used for Na⁺ and Cl⁻ ions. The studied systems were carried out at pH 7, obtaining stable adsorption between the PAA and the studied surfaces. Interestingly, the strongest adsorptions were for montmorillonite at both low and high salt concentrations. The effect of salinity differs according to the system, finding that it impairs the absorption of the polymer on montmorillonite surfaces. However, a saline medium favors the interaction with quartz and kaolinite. This is explained because montmorillonite has a lower surface charge density and a greater capacity to adsorb ions. This facilitated the adsorption of PAA. It was possible to identify that the main interaction by which the polymer is adsorbed is through the hydroxyl of the mineral surface and the COO⁻Na⁺ complexes. Molecular dynamics allows us to advance in the understanding of interactions that define the behavior of this promising reagent as an alternative for sustainable treatment of complex tailings in highly saline environments.

中文翻译：

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聚丙烯酸改善浮选尾矿管理：通过分子动力学了解化学相互作用

聚丙烯酸聚电解质 (PAA) 的分子动力学模拟分析了其与构成采矿业特征尾矿的主要矿物（在本例中为石英、高岭石和蒙脱石）的相互作用。模拟是使用 Gromacs 2020.3 包进行的。所使用的相互作用势是用于 PAA 的通用琥珀力场 (GAFF) 和用于矿物表面的 CLAYFF-MOH。SPC/E 模型描述了水分子，针对 SPC/E 模型调整的 Lennard-Jones 12-6 参数用于 Na ⁺和 Cl ^-离子。研究的系统在 pH 7 下进行，在 PAA 和研究的表面之间获得稳定的吸附。有趣的是，在低盐和高盐浓度下，对蒙脱石的吸附最强。盐度的影响因系统而异，发现它会损害聚合物在蒙脱石表面的吸收。然而，盐水介质有利于与石英和高岭石的相互作用。这是因为蒙脱石具有较低的表面电荷密度和较大的离子吸附能力。这促进了PAA的吸附。可以确定吸附聚合物的主要相互作用是通过矿物表面的羟基和 COO ^- Na ⁺复合体。分子动力学使我们能够推进对相互作用的理解，这些相互作用定义了这种有前途的试剂作为高盐环境中复杂尾矿可持续处理的替代品的行为。