器皿材料对水中全氟化合物的吸附特征研究

Adsorption of Perfluoroalkyl Substances in Aqueous Solution by Containers Made from Different Materials

  • 摘要: 全氟化合物(PFAS)因其理化性质容易吸附到固定表面,从而造成不可忽视的测量误差。研究10种PFAS(C4~C10)在7种常用的不同材质(不锈钢(Stainless steel, SS)、氧化铝(Alumina)、玻璃(Glass)、陶瓷(Ceramic)、聚苯乙烯(Polystyrene, PS)、聚丙烯(Polypropylene, PP)、聚乙烯(Polyethene, PE))容器上的吸附损失情况。结果表明:3种长链PFAS(PFOS、PFNA和PFDA)在氧化铝和PP材质容器上具有显著吸附,其在PP材料中至少7 d内可被持续累积吸附,其他材质容器对PFAS无显著吸附。不同材质容器对短链PFAS(链长 < C7)的吸附率在5 μg/L和50 μg/L条件下不显著(P>0.05),而对长链PFAS(链长≥C7)呈现显著吸附(P < 0.05)且具有浓度依赖性, 即溶液浓度越低吸附率越高。吸附机理可能涉及疏水相互作用和静电相互作用(特别是在氧化铝表面)。PFAS在不同材质容器表面的吸附随碳链长度和lg Kow的增加而增大。这些结果表明常用的PP材质容器并不适合保存环境水样品,特别是涉及长链PFAS的相关研究。本研究结果可为PFAS相关研究中实验容器的选择提供重要参考,在开展PFAS的相关研究中有必要考虑实验容器对PFAS的吸附损失。

     

    Abstract: Perfluoroalkyl substances (PFAS) have been demonstrated to be easily adsorbed on surfaces, which may result in unneglectable measurement error. The adsorption of 10 PFAS with carbon chain lengths varying from 4 to 10 onto 7 types of containers, i.e., stainless steel (SS), alumina, glass, ceramic, polystyrene (PP), polypropylene (PS), and polyethylene (PE), was investigated. The results showed that alumina and PP containers exhibited the strongest adsorption for PFAS but only for longer chain length ones (PFOS, PFNA and PFDA), and the PP containers can continuously accumulate them for at least 7 days; while no significant adsorption was observed for PS and PE containers, suggesting that they can be served as the suitable experimental materials for PFAS. Furthermore, the short-chain PFAS (chain length <C7) had no significant adsorption on container surfaces (P>0.05), regardless of the solution concentrations investigated (5 and 50 g/L), whereas the long-chain PFAS (chain length C7) showed significantly adsorption at the lower experiment concentration (P < 0.05). The underlying adsorption mechanism might be hydrophobicity and electrostatic interaction (particularly for alumina). In addition, the adsorption of PFAS on these containers increased with the increasing of chain lengths and lg Kow. These results could be helpful for selecting suitable experimental materials for PFAS and it is very essential to pay attention to the adsorption of PFAS on experimental containers in aqueous solution in the future.

     

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