Chen Wei, Duan Lin, Wang Lilin, Zhu Dongqiang
College of Environmental Science and Engineering/Tianjin Key Laboratory of Environmental Remediation and Pollution Control, Nankai University, Tianjin 300071, China.d State.
Environ Sci Technol. 2008 Sep 15;42(18):6862-8. doi: 10.1021/es8013612.
The combined effects of hydroxyl/amino functional groups of aromatics and surface O-containing groups of carbon nanotubes on adsorption were evaluated. When normalized for hydrophobicity, 2,4-dichlorophenol and 2-naphthol exhibited a greater adsorptive affinity to carbon nanotubes and graphite (a model adsorbent without the surface O functionality) than structurally similar 1,3-dichlorobenzene and naphthalene, respectively, and 1-naphthylamine exhibited a much greater adsorptive affinity than all other compounds. Results of the pH-dependency experiments further indicated that the hydroxy/amino functional groups of the adsorbates and the surface properties of the adsorbents played a combinational role in determining the significance of the nonhydrophobic adsorptive interactions. We propose that the strong adsorptive interaction between hydroxyl-substituted aromatics and carbon nanotubes/graphite was mainly due to the electron-donating effect of the hydroxyl group, which caused a strong electron-donor-acceptor (EDA) interaction between the adsorbates and the pi-electron-depleted regions on the graphene surfaces of carbon nanotubes or graphite. In addition to the EDA interaction, Lewis acid-base interaction was likely an extra important mechanism contributing to the strong adsorption of 1-naphthylamine, especially on the O-functionality-abundant carbon nanotubes. The findings of the present study might have significant implications for selective removal of environmental contaminants with carbon nanotubes.
评估了芳烃的羟基/氨基官能团与碳纳米管表面含氧基对吸附的综合影响。当按疏水性归一化时，2,4-二氯苯酚和2-萘酚分别比结构相似的1,3-二氯苯和萘对碳纳米管和石墨（一种没有表面O官能团的模型吸附剂）表现出更大的吸附亲和力，并且1-萘胺比所有其他化合物表现出大得多的吸附亲和力。pH依赖性实验结果进一步表明，吸附质的羟基/氨基官能团和吸附剂的表面性质在决定非疏水吸附相互作用的重要性方面发挥了联合作用。我们提出，羟基取代的芳烃与碳纳米管/石墨之间的强吸附相互作用主要归因于羟基的供电子效应，这导致吸附质与碳纳米管或石墨的石墨烯表面上的π电子耗尽区域之间产生强电子供体-受体（EDA）相互作用。除了EDA相互作用外，Lewis酸碱相互作用可能是导致1-萘胺强烈吸附的另一个重要机制，特别是在富含O官能团的碳纳米管上。本研究结果可能对用碳纳米管选择性去除环境污染物具有重要意义。
