10 undecylenic acid

The materials used in the presented work were used without supplementary purification. The following materials were purchased from Merck (Merck KGaA, Darmstadt, Germany): osmium tetroxide (OsO₄), sodium borohydride (NaBH₄, 96%), sodium hydroxide, and hydrochloric acid. The rest were purchased from Sigma-Aldrich (Merck KGaA, Darmstadt, Germany): p–nitrophenol, tert-butanol, i–propanol, n–decyl alcohol (n–decanol) (molar mass: 158.28 g/mol; density: 830 kg/m³; solubility in water: 0.037 mg/L), 10–undecylenic acid (1–undecenoic acid; molar mass: 184.28 g/mol, density: 912 kg/m³; solubility in water: 0.074 mg/mL).
The purified water characterized by 18.2 μS/cm conductivity was obtained with an RO Millipore system (MilliQ^® Direct 8 RO Water Purification System, Merck KGaA, Darmstadt, Germany).

Hydrochloric acid (37%), sodium borohydride (NaBH₄, 37.83 g/mol, pH value of 11 (10 g/L solution in water)), i–propanol, t–butanol and n–decanol were used without additional purification as supplied by the manufacturer (Merck KGaA, Darmstadt, Germany).
Osmium tetroxide (OsO₄), undecylenyl alcohol (11–hydroxy–1–undecene or 10–undecen–1–ol), 10–undecylenic acid or 10–undecenoic acid (>95%), and p–nitrophenol, are from Sigma-Aldrich (Merck KGaA, Darmstadt, Germany).
The pure water used for the preparation of all the solutions used in the experiments was obtained with a standard system MilliQ^® Direct 8 RO Water Purification System (Merck, Darmstadt, Germany). The characteristic conductivity of the water obtained through the reverse osmosis system is 18.2 μs/cm.
As a membrane support material, a bundle of polypropylene fibers (surface 1 m²/bundle) was purchased from GOST Ltd. (GOST Ltd., Perugia, Italy). To maintain the fibers’ characteristics, they were conditioned with polyols. Their morphological, structural and process characteristics were previously presented in detail [36 ,37 (link),38 (link)].

All reagents used in the presented work were of analytical grade. They were purchased from Merck (Merck KGaA, Darmstadt, Germany): silver nitrate, sodium chloride, sodium hydroxide, sodium chloride, sodium nitrate, hydrochloric acid, nitric acid and p-nitrophenol.
The membrane components were purchased from Sigma-Aldrich (Merck KGaA, Darmstadt, Germany): n-hexanol, n-octanol, n-decanol, n-dodecanol, 10–undecylenic acid (undecenoic acid) and undecylenic alcohol (10–undecen–1–ol or 11–hydroxy–1–undecene), and they have the characteristics presented in Table 1 [44 (link)].
The purified water characterized by 18.2 μS/cm conductivity was obtained with an RO Millipore system (MilliQ^® Direct 8 RO Water Purification System, Merck, Darmstadt, Germany).
The iron-based magnetic nanoparticles were obtained by the electrochemical method, previously presented in detail [40 (link),41 (link),42 (link)]. In this case, the electrolysis with iron electrodes was performed in pure water (to obtain magnetic nanoparticles of iron oxides) and in a silver nitrate electrolyte of 10⁻¹ mol/L (to obtain magnetic nanoparticles based on silver and iron oxides).
The obtained magnetic nanoparticles’ characteristics are presented in Table 2.