Another aspect to be considered is recyclability of the adsorbent. Again, with the same surrogate SPION system repeated water treatments of biphenyl and PCB mixtures were conducted. As ATR-FTIR spectra and thermogravimetric analyses show, no degradation of the binary SAM on the SPIONs can be observed after three cycles, nor do any pollutants remain on the particle surface after hexane washing (see Figure , supplementary information). In terms of removal performance, the removed amount of 15.34 ± 0.82 nmol in the first cycle drops by about 38% for the second and another 12 % for third cycle mostly by decrease in the removed amount of PCB 77 (see Figure , supplementary information). This could be due to remaining traces of hexane in the shell from the washing process that compete with adsorption of PCB 77. Nevertheless, the surrogate SPIONs are found to be recyclable.