Aerosil a 380

The following metal precursors and solvents were used: Titanium (IV) isopropoxide (Sigma-Aldrich, 97%), hafnium (IV) isopropoxide isopropanol adduct (Alfa Aesar, 99%), ammonium (meta)tungstate hydrate (Sigma-Aldrich, ≥85.0%), 2-ethylhexanoic acid (2-EHA) (Sigma-Aldrich, 99%), xylene (Sigma-Aldrich, ≥98.5%), ethanol absolute (VWR chemicals, ≥99.8%), diethylene glycol monobutyl ether (Sigma-Aldrich, ≥98.0%). 50 nm Au nanospheres (Citrate, BioPure^TM) in USP purified water (1 mg/mL) were purchased from nanoComposix Inc (San Diego, USA). Hydrophilic fumed silicon dioxide nanoparticles (Aerosil^®, A380) were obtained from Evonik Industries AG (Essen, Germany).

Terpolymer PAN 316020 (93.9% acrylonitrile, 5.8% methyl acrylate, 0.3% methyl sulfonate, M_w 85 kg/mol, polydispersity index 2.1) was supplied by Good Fellow, Huntingdon, UK. DMSO (99.5%, produced by Ecos-1, Moscow, Russia) was used as a solvent for PAN and a dispersion medium for silica. Hydrophilic fumed silica was used without surface modification (Aerosil A-380) (average size of individual particles ~7 nm, specific surface according to BET 380 ± 30 m²/g produced by Evonik, Essen, Germany).
PAN and silica were dried on a rotary evaporator under a vacuum of 0.05 bar at 100 °C for 4 h to constant weight before the experiments. DMSO was additionally dried over A4 molecular sieves manufactured by Sigma Aldrich (Darmstadt, Germany).

Aerosil A-380 (Evonik Degussa GmbH, Essen, Germany), magnesium acetate tetrahydrate, Mg(CH₃COO)₂·4H₂O (ACS reagent, ≥98%, Merck, KGaA, Darmstadt, Germany), manganese(II) acetate tetrahydrate, Mn(CH₃COO)₂·4H₂O, (99.99%, Sigma-Aldrich, KGaA, Darmstadt, Germany), nickel(II) acetate tetrahydrate, Ni(CH₃COO)₂·4H₂O (98%, Sigma-Aldrich), copper(II) acetate hydrate, Cu(CH₃COO)₂·H₂O, zinc acetate dehydrate, Zn(CH₃COO)₂·2H₂O (ACS reagent, ≥98%, Sigma-Aldrich), resorcinol (99.9%, Chimlaborreativ, Brovary, Ukraine) and a 37% aqueous solution of formaldehyde ((stabilized with about 10% methanol) for synthesis, Sigma-Aldrich) were used in the synthesis of composites. Double-distilled water was used as the solvent. In the adsorption experiment, 4-nitrophenol and 4-chlorophenol, delivered by Merck (Darmstadt, Germany), were used as adsorbates.