Programa Institucional de Fomento a la Investigación, Desarrollo e Innovación, Universidad Tecnológica Metropolitana, Ignacio Valdivieso 2409, San Joaquín, Santiago 8940577, Chile.
Centro Integrativo de Biología y Química Aplicada (CIBQA), Universidad Bernardo O'Higgins, General Gana 1702, Santiago, 8370854, Chile.
Sci Total Environ. 2023 Sep 15;891:164470. doi: 10.1016/j.scitotenv.2023.164470. Epub 2023 May 24.
Urban wastewaters comprise different hydrophobic pollutants such as microplastics (MPs), pharmaceuticals, and personal care products. Among these pollutants, triclosan (TCS) shows a worrying interaction ability with MPs; recent studies show MPs serve as a vector between TCS and aquatic environments, whose interaction is still being studied to understand their combined toxicity and transport ability. Using computational chemistry tools, this work evaluates the TCS-MPs interaction mechanism, including pristine polymers, i.e., aliphatic polyamides (PA), polyethylene (PE), polystyrene (PS), polyvinyl chloride (PVC), and polyethylene terephthalate (PET). Our results show that TCS adsorption on MPs solely occurs via physisorption, where PA reaches the higher adsorption ability. Remarkably, MPs reach higher or comparable adsorption stability than carbon-based materials, boron nitrides, and minerals, indicating their worrying transport properties. Also, the adsorption capacity is strongly influenced by entropy changes rather than thermal effects, which determine the different sorption capacities among polymers and agree well with reported sorption capacities from adsorption kinetic experiments in the literature. MPs show a polar and highly susceptible surface to establish electrostatics and dispersion effects on TCS. Accordingly, the TCS-MPs interaction mechanism arises from the interplay between electrostatics and dispersion forces, with a combined contribution of 81-93 %. Specifically, PA and PET maximize the electrostatic effects, while PE, PP, PVC, and PS maximize the dispersion effects. From the chemical viewpoint, TCS-MPs complexes interact by a series of pairwise interactions such as Van der Waals, hydrogen bonding, C-H⋯π, C-H⋯C-H, C-Cl⋯C-H, and C-Cl⋯Cl-C. Finally, the mechanistic information explains the effects of temperature, pressure, aging, pH, and salinity on TCS adsorption. This study quantitatively elucidates the interaction mechanism of TCS-MP systems, which were hard to quantify to date, and explains the TCS-MPs sorption performance for sorption/kinetic studies.
城市废水中包含多种疏水性污染物，如微塑料 (MPs)、药物和个人护理产品。在这些污染物中，三氯生 (TCS) 显示出与 MPs 令人担忧的相互作用能力；最近的研究表明 MPs 是 TCS 和水生环境之间的媒介，它们的相互作用仍在研究中，以了解它们的联合毒性和迁移能力。本工作使用计算化学工具评估 TCS-MPs 相互作用机制，包括原始聚合物，即脂肪族聚酰胺 (PA)、聚乙烯 (PE)、聚苯乙烯 (PS)、聚氯乙烯 (PVC) 和聚对苯二甲酸乙二醇酯 (PET)。研究结果表明，TCS 仅通过物理吸附吸附在 MPs 上，其中 PA 达到了更高的吸附能力。值得注意的是， MPs 达到了更高或可比的吸附稳定性，超过了基于碳的材料、氮化硼和矿物质，表明其具有令人担忧的迁移特性。此外，吸附容量强烈受熵变影响，而不受热效应影响，这决定了聚合物之间不同的吸附容量，与文献中吸附动力学实验报告的吸附容量吻合较好。 MPs 表现出极性和高度敏感的表面，可在 TCS 上建立静电和分散作用。因此，TCS-MPs 相互作用机制源于静电和分散力之间的相互作用，综合贡献为 81-93%。具体来说，PA 和 PET 最大程度地增强了静电效应，而 PE、PP、PVC 和 PS 则最大程度地增强了分散效应。从化学角度来看，TCS-MPs 配合物通过一系列成对相互作用相互作用，如范德华力、氢键、C-H⋯π、C-H⋯C-H、C-Cl⋯C-H 和 C-Cl⋯Cl-C。最后，该机理信息解释了温度、压力、老化、pH 值和盐度对 TCS 吸附的影响。本研究定量阐明了 TCS-MP 系统的相互作用机制，这在以前是难以量化的，并解释了 TCS-MPs 吸附性能，以用于吸附/动力学研究。
