*4.2. Treatment Process*

Zero-valent iron (Ferox Target, 325 mesh) was supplied by Hepure (Hillsborough, NJ, USA). Hematite (10 µm) was supplied by Kremer (Aichstetten, Germany); magnetite (10 µm) was supplied by Kremer (Aichstetten, Germany); 30% H2O<sup>2</sup> solution was supplied by Stanlab (Lublin, Poland).

Doses of H2O2, Fe<sup>0</sup> , magnetite, and hematite were selected in preliminary tests. Treatment processes were carried out in a 1.5 L reactor filled with 1 L of the sample, stirred at 300 rpm (Heidolph MR3000, Schwabach, Germany). pH in the treatment processes was set to 3.0, unless otherwise stated. The experiment on the influence of pH on the efficiency of the process was carried out at pH 2.0, 3.0, 4.0, 5.0 and 6.0. Samples were taken after 15, 30, 60 and 120 min of the process. The process was stopped as a result of alkalization to pH 9.0 with 3M NaOH (POCh, Gliwice, Poland).

The source of radiation was medium-pressure Fe/Co 400W lamp type HPA 400/30 SDC with 94W UVA power (Philips, Amsterdam, The Netherlands). The lamp spectrum is shown in Figure S3. Details of the experiment setup are shown in Table S1.
