2012 Volume 53 Issue 4 Pages 739-744
Nano-sized iron oxide particles were prepared by electrical wire explosion (EWE) for As(III) removal. The electrical explosion of Fe wire in Ar–5%O2, Ar–10%O2, and Ar–30%O2 produced a wide spectrum of iron–oxide phases from wüstite to hematite depending on the oxygen partial pressure in the chamber. An increase in oxygen partial pressure tended to shift the iron oxides towards higher oxidation states. The major phase of the explosion product was verified as the magnetite (Fe3O4)–maghemite (γ-Fe2O3) mixture through the step scan of (511) and (440) peaks. The As(III) removal capacity and saturation magnetization were found to be proportional to the amount of zero-valent iron (ZVI) in the particles. The As(III) adsorption capacity (qmax, mg/g) calculated from the Langmuir isotherm was 19.7, 9.46, and 3.55 mg/g for particles synthesized in Ar–5%O2, Ar–10%O2, and Ar–30%O2, respectively. The EWE process could be utilized to produce nano-sized adsorbent particles with a wide range of As(III) removal capability simply by varying the gas mixture. The eco-friendly nature of EWE process combined with the magnetic separation option would add to the list of the successful As(III) removal adsorbents.