Adsorption and conformation of a cationic surfactant on single-walled carbon nanotubes and their influence on naphthalene sorption.
Adsorption and conformation of a cationic surfactant on single-walled carbon nanotubes and their influence on naphthalene sorption.
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DOI：
10.1021/es902173v
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发表时间：
2010-01
影响因子：
11.4
通讯作者：
Kun Yang;Qing-feng Jing;Wenhao Wu;Lizhong Zhu;B. Xing
中科院分区：
文献类型：
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作者：
Kun Yang;Qing-feng Jing;Wenhao Wu;Lizhong Zhu;B. Xing
表面活性剂用于碳纳米管（CNT）的合成和分散，因此可以与CNT一起释放到环境中。在这项研究中，它被观察到，耦合释放的表面活性剂和碳纳米管改变了吸附的碳纳米管上的有机污染物。阳离子表面活性剂氯化十六烷基吡啶（CPC）降低了萘在单壁碳纳米管（SWCNT）上的吸附。在最引人注目的实例中，萘在SWCNT上的吸附容量从240 mg/g降低到61.1 mg/g。萘吸附的减少可以在很大程度上归因于吸附的CPC阳离子的竞争（即，C（21）H（38）N（+））与萘通过占据单壁碳纳米管表面作为表面积从737 m（2）/g降低到CPC涂覆后的88.9 m（2）/g。然而，吸附的CPC可能形成半胶束，并导致一个有利的介质萘分配抵消萘吸附的减少。吸附CPC半胶束的构型可能发生变化，因为萘分配到吸附CPC的增加而减少。引入分配-吸附模型来描述萘在CPC半胶束中的分配分数以及萘在单壁碳纳米管空表面上的吸附分数。
Surfactants are used in synthesis and dispersion of carbon nanotubes (CNTs) and can thus be released into the environment with CNTs. In this study, it was observed that the coupled release of surfactants and CNTs altered the sorption of organic contaminants on the CNTs. The cationic surfactant, cetylpyridinium chloride (CPC), decreased naphthalene sorption on single-walled carbon nanotubes (SWCNT). In the most dramatic example, the adsorption capacity of naphthalene on SWCNT was reduced from 240 to 61.1 mg/g. The decrease of naphthalene sorption could be largely attributed to the competition of adsorbed CPC cations (i.e., C(21)H(38)N(+)) with naphthalene by occupying the SWCNT surface as surfaces decreased from 737 to 88.9 m(2)/g after the coating of CPC. However, the adsorbed CPC may form hemimicelles and result in a favorable media for naphthalene partition to counteract the decrease in naphthalene sorption. Configuration changes of adsorbed CPC hemimicelles might occur because the naphthalene partition into the adsorbed CPC decreased with the increase of adsorbed CPC. A partition-adsorption model was introduced to describe the partition fraction of naphthalene into adsorbed CPC hemimicelles as well as the adsorption fraction of naphthalene on unoccupied surfaces of SWCNT.