Contribution of different sulfamethoxazole species to their overall adsorption on functionalized carbon nanotubes.
Contribution of different sulfamethoxazole species to their overall adsorption on functionalized carbon nanotubes.
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DOI：
10.1021/es903851q
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发表时间：
2010-04
影响因子：
11.4
通讯作者：
Di Zhang;B. Pan;Huang Zhang;P. Ning;B. Xing
中科院分区：
文献类型：
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作者：
Di Zhang;B. Pan;Huang Zhang;P. Ning;B. Xing
抗生素具有环境风险，但其吸附机制仍不清楚。确定不同机制的贡献对于预测抗生素的环境行为，从而了解其环境风险至关重要。本研究以功能化碳纳米管(CNTs)为吸附剂，以磺胺甲恶唑(SMX)为吸附剂，研究了可电离有机污染物在固体颗粒上的吸附机理。在pH值为3.7时，SMX对不同碳纳米管的吸附效果最好，吸附顺序为：MH>；MG>；MC。结合SMX物种分析的结果，pH依赖的吸附可以很好地解释为疏水作用和电子供体-受体相互作用。中性SMX的吸附始终占主导地位，一般占总吸附的80%以上。阳离子SMX在pH和lt；3.5时的显著贡献表明氢键对SMX吸附有显著贡献。双酚A(BPA)抑制SMX吸附的强度依赖于BPA与中性SMX的浓度比，而不是SMX的总浓度。这一结果强调了确定抗生素吸附的主要机制或物种的重要性。
Antibiotics pose environmental risks, but their adsorption mechanisms are still unclear. Identifying the contributions of different mechanisms is vital in predicting antibiotic environmental behavior and consequently understanding their environmental risks. This study used functionalized carbon nanotubes (CNTs), namely hydroxylized (MH), carboxylized (MC), and graphitized (MG) multiwalled CNTs, as adsorbents and sulfamethoxazole (SMX) as an adsorbate to study the adsorption mechanisms of ionizable organic contaminants on solid particles. At pH around 3.7, SMX always showed the highest adsorption on different CNTs and the adsorption followed the order of MH > MG > MC. Combining the results on SMX specie analysis, the pH-dependent adsorption is well-explained by hydrophobic and electron-donor-acceptor interactions. The adsorption of neutral SMX is always dominant by contributing generally over 80% to the overall adsorption. A significant contribution of cationic SMX at pH < 3.5 suggested significant contribution of hydrogen bonds to SMX adsorption. The strength of bisphenol A (BPA) inhibiting SMX adsorption was dependent on the concentration ratio of BPA to neutral SMX, instead of to the overall SMX concentration. This result emphasized the importance of identifying the dominant mechanisms or species for the adsorption of antibiotics.