Sorption of Heterocyclic Organic Compounds to Multiwalled Carbon Nanotubes.
Sorption of Heterocyclic Organic Compounds to Multiwalled Carbon Nanotubes.
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DOI：
10.1021/acs.est.7b05205
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发表时间：
2018-01
影响因子：
11.4
通讯作者：
Florian Metzelder;Matin Funck;T. Schmidt
中科院分区：
文献类型：
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作者：
Florian Metzelder;Matin Funck;T. Schmidt
吸附是一个重要的自然和技术过程。吸附系数通常在分批实验中确定，但这对于弱吸附化合物可能具有挑战性。能够分析这些化合物的替代方法是柱色谱法。使用填充有吸附剂的柱，并通过将吸附剂保留与非阻滞示踪剂的保留相关来确定吸附数据。在这项研究中，柱色谱法首次应用于研究吸附以前几乎没有调查杂环有机化合物的多壁碳纳米管（MWCNTs）。这些化合物的吸附数据在文献中非常有限，预计吸附较弱。氧化氘被用作非延迟示踪剂。吸附等温线很好地描述了Freundlich模型和数据显示合理的协议与预测值。吸附是放热和物理吸附观察。氢键可能有助于整体吸附，这是支持减少吸附与离子强度增加，由于封闭的官能团。降低pH值减少了可电离化合物的吸附，这是由于在pH 3时吸附剂和山梨酸酯带正电的静电排斥。总之，柱色谱法成功地用于研究吸附杂环化合物的多壁碳纳米管，并可应用于其他碳基吸附剂。
Sorption is an important natural and technical process. Sorption coefficients are typically determined in batch experiments, but this may be challenging for weakly sorbing compounds. An alternative method enabling analysis of those compounds is column chromatography. A column packed with the sorbent is used and sorption data are determined by relating sorbate retention to that of a nonretarded tracer. In this study, column chromatography was applied for the first time to study sorption of previously hardly investigated heterocyclic organic compounds to multiwalled carbon nanotubes (MWCNTs). Sorption data for these compounds are very limited in literature, and weak sorption is expected from predictions. Deuterium oxide was used as nonretarded tracer. Sorption isotherms were well described by the Freundlich model and data showed reasonable agreement with predicted values. Sorption was exothermic and physisorption was observed. H-bonding may contribute to overall sorption, which is supported by reduced sorption with increasing ionic strength due to blocking of functional groups. Lowering pH reduced sorption of ionizable compounds, due to electrostatic repulsion at pH 3 where sorbent as well as sorbates were positively charged. Overall, column chromatography was successfully used to study sorption of heterocyclic compounds to MWCNTs and could be applied for other carbon-based sorbents.