Mass-production of iron nanopowders by liquid-phase reductive precipitation in a rotating packed bed with blade packings

Abstract

Iron nanopowders were mass-produced using liquid-phase reductive precipitation and a rotating packed bed (RPB) with blade packings. The effects of the concentration of the reactants, iron valence, iron source, rotational speed, and flow rates of the reactants on the characteristics of the iron nanopowders were studied. The highest mass-production rate was around 13 kg/day, which was obtained using an FeCl2 concentration of 0.2 mol/L, an NaBH4 concentration of 0.4 mol/L, a rotational speed of 1800 rpm, a flow rate of aqueous FeCl2 of 0.9 L/min, and a flow rate of aqueous NaBH4 of 0.9 L/min. The mean size of the iron nanopowders that were mass-produced using this process was 42 nm, as determined by TEM. Therefore, an RPB with blade packings can be effectively used in the commercial production of iron nanopowders. The degradation of sulfamethazine (SMT) by persulfate in water was used to evaluate the activity of the iron nanopowders in the activation of persulfate. At 25 °C, a degradation time of 30 min, an initial SMT concentration of 10 mg/L, an iron nanopowders dosage of 0.028 g/L, and an Na2S2O8 concentration of 0.24 g/L, the efficiency of degradation of SMT by the mass-produced iron nanopowders was 97%, which greatly exceeded the 9% that was achieved using commercial iron nanopowders that had been purchased from Alfa Aesar. The results herein indicate that the mass-produced iron nanopowders with persulfate is highly effective for degrading SMT in water.