Characteristics of iron oxide rust prepared by peracetic acid and its removal of heavy metals in water

Abstract

Fe2O3 is an especially promising material for water purification as it shows high heavy metal adsorption capacity. However, the high cost of commercial Fe2O3 makes it difficult to be widely used in developing countries. Herein, we probe the heavy metal removal performance of iron oxide rust. Rust was grown on iron nails in a controlled manner using peracetic acid (CH3CO3H), a safe and environment-friendly oxidizer. Arsenic was selected as an example of a heavy metal contaminant in this study. XRD and EDS analysis revealed that the iron oxide prepared with peracetic acid was nearly amorphous Fe2O3. Amorphous iron oxide is reported to show higher reactivity than crystalline iron oxide. The BET specific surface area of prepared Fe2O3 is 71 m2/g, which is larger than that of commercial Fe2O3, and the average pore diameter is 73 Å. Oxidized nails are highly effective for removing heavy metals: about 90% of 1ppm arsenic in water was removed at the residence time of 20 minutes, and the removal rate of 90% is maintained after 10 back-to-back arsenic removal experiments at the same residence time. Iron oxide prepared in this study can remove, per 1 cm2, up to 0.114 mg of arsenic.