Mixed Maghemite/Hematite Iron Oxide Nanoparticles Synthesis for Lead and Arsenic Removal from Aqueous Solution

This work focused on the synthesis of iron oxide nanoparticles by the coprecipitation method with three basic solutions, namely, NH4OH, KOH, and NaOH. The synthesized iron oxides were characterized by various techniques such as XRD, MET, BET, and a SQUID magnetometer. The results showed nanosized particles of 13.2, 9.17, and 8.42 nm and different phases associated to maghemite and maghemite/hematite. The surface areas were 113, 94, and 84 m2/g and the magnetization strength were 58, 61, and 75 emu/g to iron oxides synthesized with NaOH, KOH, and NH4OH, respectively. The magnetic iron oxides obtained using NaOH were more efficient in the removal of lead and arsenic by adsorption than iron oxides obtained with KOH and NH4OH. However, the magnetic strength decreases using NaOH and KOH. The highest adsorption capacities attained for lead and arsenic removal were 16.6 and 14 mg/g, respectively, using NaOH-based iron oxides.