Amphiphilic core–shell magnetic adsorbents for efficient removal and detection of phthalate esters

A new class of amphiphilic magnetic adsorbents (denoted as Fe 3 O 4 -GPS-A) is fabricated by functionalization of the Fe 3 O 4 surface with six different amphiphilic silanizing agents that are specifically tailor-made to the chemical structure of PAEs. The resulting Fe 3 O 4 -GPS-A exhibit different contact angles due to the significant changes in functional groups, as revealed by 1 H NMR and FTIR spectroscopy. Among six Fe 3 O 4 -GPS-A, Fe 3 O 4 -DOA and Fe 3 O 4 -OAN exhibit a fast adsorption process (within 60 min) and high adsorption capacity for dibutyl phthalate (DBP) and dioctyl phthalate (DOP), two commonly used phthalate esters (173.7 mg g −1 for DOP and 104.4 mg g −1 for DBP), in conjunction with fast magnetic responsiveness and good thermal stability. The adsorption performance of Fe 3 O 4 -DOA and Fe 3 O 4 -OAN were well-maintained even after ten cycles. Besides, the adsorption mechanism was investigated through adsorption fitting models and theoretical calculations, which inferred that the interactions between adsorbent and adsorbate are mainly based on hydrophobic interactions along with secondary non-covalent contacts. Finally, the adsorbents combined with GC–MS analyses were applied to monitor DBP and DOP in the lake water samples. This work not only opens up a strategy for amphiphilic modification of magnetic adsorbents, but also provides a new avenue in their application for phthalate esters detection.