Adsorption of phenanthrene on multilayer graphene as affected by surfactant and exfoliation.
Adsorption of phenanthrene on multilayer graphene as affected by surfactant and exfoliation.
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DOI：
10.1021/es403873r
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发表时间：
2014
影响因子：
11.4
通讯作者：
Jian Zhao;Zhenyu Wang;Qing Zhao;B. Xing
中科院分区：
文献类型：
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作者：
Jian Zhao;Zhenyu Wang;Qing Zhao;B. Xing
采用被动给药技术研究了表面活性剂介导的多层石墨烯剥离及其对菲吸附的影响。在不添加表面活性剂（胆酸钠，NaC）的情况下，多层石墨烯由于比表面积和微孔体积更大，对菲的吸附能力高于碳纳米管和石墨。观察到的脱附滞后可能是由于石墨烯片的折叠和重排形成封闭的间隙造成的。当NaC存在（100和8000 mg/L）时，由于NaC分子在石墨烯表面的直接竞争，菲在石墨烯上的吸附减少。在超声的辅助下，NaC对多层石墨烯片进行剥离，得到了较好的分散效果。分散程度取决于水溶液中石墨烯-NaC的比例，而不是NaC的临界胶束浓度，NaC分子在石墨烯片上达到吸附饱和后才会出现良好的分散。此外，剥落削弱了菲和NaC之间的竞争，由于暴露了新的位点，石墨烯对菲的吸附能力增强。石墨烯薄片的剥落和相关吸附性能的研究结果不仅突出了多层石墨烯作为高效吸附剂的潜在应用，也突出了其可能的环境风险。
Surfactant mediated exfoliation of multilayer graphene and its effects on phenanthrene adsorption were investigated using a passive dosing technique. In the absence of surfactant (sodium cholate, NaC), multilayer graphene had higher adsorption capacity for phenanthrene than carbon nanotube and graphite due to the higher surface area and micropore volume. The observed desorption hysteresis is likely caused by the formation of closed interstitial spaces through folding and rearrangement of graphene sheets. In the presence of NaC (both 100 and 8000 mg/L), phenanthrene adsorption on graphene was decreased due to the direct competition of NaC molecules on the graphene surface. With the aid of sonication, multilayer graphene sheets were exfoliated by NaC, leading to better dispersion. The degree of dispersion depended on the graphene-NaC ratio in aqueous solution rather than critical micelle concentration of NaC, and the good dispersion occurred after reaching adsorption saturation of NaC molecules on graphene sheets. In addition, exfoliation weakened the competition between phenanthrene and NaC and enhanced the adsorption capacity of graphene for phenanthrene due to exposed new sites. The findings on exfoliation of graphene sheets and related adsorption properties highlight not only the potential applications of multilayer graphene as efficient adsorbent but also its possible environmental risk.