Mechanisms for strong adsorption of tetracycline to carbon nanotubes: A comparative study using activated carbon and graphite as adsorbents
Mechanisms for strong adsorption of tetracycline to carbon nanotubes: A comparative study using activated carbon and graphite as adsorbents
复制标题
碳纳米管强吸附四环素的机理：活性炭和石墨作为吸附剂的对比研究
DOI：
10.1021/es803268b
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发表时间：
2009-04-01
影响因子：
11.4
通讯作者：
Zhu, Dongqiang
中科院分区：
文献类型：
--
作者：
Ji, Liangliang;Chen, Wei;Zhu, Dongqiang
对水生环境中存在的抗生素（包括四环素类）的严重关切已引起人们的关注。本文研究了单壁碳纳米管（SWNT）和多壁碳纳米管（MWNT）作为去除水溶液中四环素的潜在有效吸附剂。相比之下，非极性吸附质，萘，和其他两个碳质吸附剂，粉末活性炭（AC）和无孔石墨，被使用。四环素在单壁碳纳米管、多壁碳纳米管、活性炭和石墨上的吸附-溶液分配系数分别为10（4）-10（6）L/kg、10（4）-10（6）L/kg、10（3）-10（4）L/kg和10（3）-10（5）L/kg。对吸附剂表面积进行归一化处理后，四环素的吸附亲和力依次为石墨/单壁碳纳米管>多壁碳纳米管>>活性炭。四环素对AC的较弱吸附表明，对于大体积吸附物，吸附亲和力受可用吸附位点的可及性影响很大。四环素对碳纳米管和石墨的显著强吸附可归因于与石墨烯表面的强吸附相互作用（货车范德华力、π-π电子-供体-受体相互作用、阳离子-π键合）。四环素与模型石墨烯化合物（萘、菲、芘）在溶液相中的络合作用通过四环素部分的环电流诱导的H-1 NMR高场化学位移来验证。
Significant concerns have been raised over the presence of antibiotics including tetracyclines in aquatic environments. We herein studied single-walled carbon nanotubes (SWNT) and multi-walled carbon nanotubes (MWNT) as potential effective adsorbents for removal of tetracycline from aqueous solution. In comparison, a nonpolar adsorbate, naphthalene, and two other carbonaceous adsorbents, pulverized activated carbon (AC) and nonporous graphite, were used. The observed adsorbent-to-solution distribution coefficient (K-d, L/kg) of tetracycline was in the order of 10(4)-10(6) L/kg for SWNT, 10(4)-10(6) L/kg for MWNT, 10(3)-10(4) L/kg for AC, and 10(3)-10(5) L/kg for graphite. Upon normalization for adsorbent surface area, the adsorption affinity of tetracycline decreased in the order of graphite/SWNT > MWNT >> AC. The weaker adsorption of tetracycline to AC indicates that for bulky adsorbates adsorption affinity is greatly affected by the accessibility of available adsorption sites. The remarkably strong adsorption of tetracycline to the carbon nanotubes and to graphite can be attributed to the strong adsorptive interactions (van der Waals forces, pi-pi electron-donor-acceptor interactions, cation-pi bonding) with the graphene surface. Complexation between tetracycline and model graphene compounds (naphthalene, phenanthrene, pyrene) in solution phase was verified by ring current-induced H-1 NMR upfield chemical shifts of tetracycline moieties.