State Environmental Protection Key Laboratory of Wetland Ecology and Vegetation Restoration, College of Urban and Environmental Sciences, Northeast Normal University, Changchun 130024, PR China.
Chemosphere. 2013 Jul;92(4):429-34. doi: 10.1016/j.chemosphere.2013.01.039. Epub 2013 Feb 12.
As an important part of dissolved organic matter (DOM), low molecular weight organic acids (LOAs) may play a key role in the process for DOM stabilizing carbon nanomaterials (e.g. C60) suspensions in aquatic environment. In addition, both LOAs and C60 have been detected in the troposphere and therefore have a chance to interact with each other in the gaseous phase. However, the mechanism for LOAs-C60 interactions and their environmental implications need further investigations. In this study, molecular dynamics (MD) simulation was employed to investigate the interactions between both neutral and ionic LOAs with C60 in vacuum and water. The results showed that the adsorptions of all LOAs on C60 in energy are favorable, and the aromatic acids have stronger interactions with C60 than the aliphatic acids in vacuum and water. The interaction energies (Eint) of the LOA anions with C60 were weaker than those of their corresponding neutral LOA molecules. The models were also developed to predict and interpret Eint based on the results from MD simulations. Dispersion, induction and hydrophobic interactions were found to be the dominating factor in Eint. These findings indicate that cost-efficient MD simulation can be employed as an important tool to predict the adsorption behavior of LOAs on carbon nanomaterials.
作为溶解有机物质 (DOM) 的重要组成部分，低分子量有机酸 (LOAs) 可能在 DOM 稳定碳纳米材料 (例如 C60) 悬浮液的过程中发挥关键作用。此外，LOAs 和 C60 都在平流层中被检测到，因此它们有机会在气相中相互作用。然而，LOAs-C60 相互作用的机制及其环境影响需要进一步研究。在这项研究中，采用分子动力学 (MD) 模拟来研究中性和离子型 LOAs 与 C60 在真空中和水中的相互作用。结果表明，所有 LOAs 在能量上对 C60 的吸附都是有利的，并且在真空中和水中，芳香酸与 C60 的相互作用比脂肪酸更强。LOA 阴离子与 C60 的相互作用能弱于相应中性 LOA 分子。还建立了模型来根据 MD 模拟的结果预测和解释 Eint。发现色散、诱导和疏水相互作用是 Eint 的主要因素。这些发现表明，具有成本效益的 MD 模拟可以作为一种重要工具来预测 LOAs 在碳纳米材料上的吸附行为。
