Hg0 chemisorption of magnetic manganese cobalt nano ferrite from simulated flue gas

Abstract

Mercury (Hg) emissions from the flue gas of coal-fired power plants constituted the primary source of atmospheric mercury pollution, manifesting in three distinct forms: granular mercury, oxidized mercury, and elemental mercury. This pollution posed significant threats to the ecological environment. There was an urgent demand for a more effective and economically viable mercury removal technology. The magnetic Mn0.5Co0.5Fe2O4 nanoparticles were prepared via a rapid combustion process. Their capacities for mercury adsorption and regeneration were scrutinized through a fixed-bed experimental system. The outcomes revealed that Mn0.5Co0.5Fe2O4 nanoparticles, prepared at a calcination temperature of 400 °C with 20 ml of anhydrous ethanol, exhibited the most proficient adsorption of Hg°. Under these specific conditions, the average particle size of the Mn0.5Co0.5Fe2O4 nanoparticles was approximately 26.8 nm. These nanoparticles demonstrated a superior adsorption capacity of 9.48 μg·g−1 for Hg° at an adsorption temperature of 30 °C under a space velocity of 2.4 × 104 h−1. Elevating the permeation temperature to 70 °C resulted in an impressive adsorption capacity for Hg°, reaching 560.59 μg·g−1. The Hg-TPD (Hg-Temperature Programmed Desorption) and XPS (X-ray photoelectron spectroscopy) analyses revealed the involvement of chemisorbed oxygen (Oads), Mn3+, and Fe3+ in the adsorbent, facilitating the oxidation of Hg° and generating HgO on the adsorbent surface. Following six cycles of adsorption and desorption, the adsorption capacity of Mn0.5Co0.5Fe2O4 nanoparticles for Hg° retained 71% of the first adsorption capacity, which indicated that magnetic Mn0.5Co0.5Fe2O4 nanoparticles held great promise as an adsorbent for mercury removal.