Hydrogen chloride

(-)-Epicatechin (EC), quercetin (Quer), ampicillin sodium salt, nistatine, agar, yeast extract, cholesterol, 5-fluoro-2′-deoxyuridine (FUdR), and bovine serum albumin were purchased from Sigma-Aldrich (Madrid, Spain). Sodium chloride, calcium chloride, 10% w/v sodium hypochlorite solution, hydrogen chloride, sodium hydroxide and dimethyl sulfoxide (DMSO) were obtained from Panreac (Barcelona, Spain). Potassium dihydrogen phosphate, potassium monohydrogen phosphate, sodium monohydrogen phosphate, acetic acid and magnesium sulfate were from Merck (Darmstadt, Germany). Petri plates Ø 35 and 60 mm were from Brand GMBH (Wertheim, Germany) and Petri plates Ø 90 mm from Francisco Soria Melguizo (Valdemoro, Madrid). MRS Broth was from Fisher Scientific (Madrid, Spain) and tryptone medium from Fluka Analytical (Madrid, Spain).

The organic pollutant OG
(7-hydroxy-8-[(E)-phenyldiazenyl] naphthalene-1,3-disulfonic
acid, C₁₆H₁₀N₂Na₂O₇S₂, azo dye) (Figure 1) and titanium dioxide (TiO₂)
were purchased from Biochem, Germany, with purity >98%. To prepare
γ-Fe₂O₃, iron(II) chloride (FeCl₂·4H₂O, 99%) and iron(III) chloride (FeCl₃, 97%) were purchased from Fluka and Sigma-Aldrich, Spain. Sodium
hydroxide (NaOH, 98%) and hydrogen chloride (HCl, 37%) were obtained
from Panreac, Germany. tert-Butanol (TBA), benzoquinone
(BQ), and ethylenediaminetetraacetic acid disodium salt (EDTA-2Na)
were purchased from Sigma-Aldrich. Hydrogen peroxide (H₂O₂, 30%) was purchased from SialChim Reagent Ltd., and
ethanol at 96.3% in analytical grade was obtained from VWR Chemicals.
Experimental solutions were prepared with doubly distilled water,
and all reagents were used without further purification.