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

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 K_ow. 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.