Instrumental Analytical Chemistry, University of Duisburg-Essen, Universitätsstrasse 5, 45141 Essen, Germany; Department of Environmental Geosciences, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria; Centre for Water and Environmental Research ZWU, University of Duisburg-Essen, Universitätsstrasse 2, 45141 Essen, Germany.
Helmholtz Centre for Environmental Research UFZ, Permoserstrasse 15, 04318 Leipzig, Germany.
Water Res. 2014 Aug 1;59:295-303. doi: 10.1016/j.watres.2014.04.029. Epub 2014 Apr 24.
The accurate prediction of distribution coefficients of organic compounds from water to carbon-based nanomaterials (CNM) is of major importance for the understanding of environmental processes and a risk assessment of released CNM. Poly-parameter linear free-energy relationships (ppLFER) have previously been shown to offer such an accurate prediction of sorption processes. The aim of this study was to identify and quantify the contribution of individual molecular interactions to overall sorption by multi-walled carbon nanotubes (MWCNTs). To this end, a large data set of experimental sorption isotherms by MWCNTs of 20 aliphatic and 14 aromatic compounds covering various relevant molecular interactions was produced. A thermodynamic cycle was used to obtain MWCNT-air distribution coefficients (KMWCNT/a) for the interpretation of direct sorbate-MWCNTs interactions. The thereby derived ppLFER log KMWCNT/a = (0.59 ± 0.59)E + (2.23 ± 0.59)S + (3.90 ± 0.67)A + (3.23 ± 0.71)B + (0.98 ± 0.17)L - (0.05 ± 0.50) shows the contribution of non-specific interactions, represented by the hexadecane-air partitioning constant (L), and specific interactions related to the solute polarity (S) as well as the H-bond interactions (A, B). Measured MWCNT-water distribution coefficients were clearly more accurately calculated by the ppLFER equations (R(2) 0.85-0.86) compared to the classical prediction by single parameter model based on the octanol-water partitioning constant (R(2) 0.64-0.78). In addition, the ppLFER presented here allow a more accurately prediction of sorption by MWCNTs compared to literature ppLFER, especially for aliphatic compounds and at environmentally relevant concentrations.
准确预测有机化合物从水到基于碳的纳米材料（CNM）的分布系数对于理解环境过程和评估释放的 CNM 的风险至关重要。多参数线性自由能关系（ppLFER）先前已被证明可对吸附过程进行如此准确的预测。本研究的目的是确定和量化单个分子相互作用对多壁碳纳米管（MWCNT）整体吸附的贡献。为此，生成了一个由 20 种脂肪族和 14 种芳香族化合物的 MWCNT 实验吸附等温线组成的大型数据集，涵盖了各种相关的分子相互作用。使用热力学循环获得 MWCNT-空气分配系数（KMWCNT/a）以解释直接吸附剂-MWCNT 相互作用。由此得出的 ppLFER 对数 KMWCNT/a =（0.59 ± 0.59）E +（2.23 ± 0.59）S +（3.90 ± 0.67）A +（3.23 ± 0.71）B +（0.98 ± 0.17）L -（0.05 ± 0.50）表明非特异性相互作用的贡献，由十六烷-空气分配常数（L）表示，以及与溶质极性（S）以及氢键相互作用（A，B）相关的特异性相互作用。与基于辛醇-水分配常数的经典预测（R（2）0.64-0.78）相比，ppLFER 方程（R（2）0.85-0.86）明显更准确地计算了测量的 MWCNT-水分配系数。此外，与文献中的 ppLFER 相比，此处提出的 ppLFER 允许更准确地预测 MWCNT 的吸附，特别是对于脂肪族化合物和环境相关浓度。
