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 Hg0. 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 Hg0 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 Hg0, 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 Hg0 and generating HgO on the adsorbent surface. Following six cycles of adsorption and desorption, the adsorption capacity of Mn0.5Co0.5Fe2O4 nanoparticles for Hg0 retained 71% of the first adsorption capacity, which indicated that magnetic Mn0.5Co0.5Fe2O4 nanoparticles held great promise as an adsorbent for mercury removal.

Adsorption of magnetic manganese ferrites to simulated monomeric mercury in flue gases

“…Among them, magnetic ferrite nanomaterials are a new type of material that offers the advantages of easy separation, recyclability, and environmental friendliness, so they have been widely applied in organic and biological separations. Especially, they are excellent adsorbents due to their large specific surface area, abundant active sites, and interfacial effect [17][18][19]. Simultaneously, manganese oxides can impact the mercury cycle by adsorbing it, influencing the ambient redox potential and regulating microorganism activity.…”

Regulating coordination environment around transition metal (Fe, Co) single atom catalysts for efficient Hg0 adsorption

“…Mercury (Hg) is a highly toxic heavy metal that exists in liquid form at room temperature and is easily vaporized, which can cause environmental pollution [1]. It is one of the main pollutants in coal combustion, including: elemental mercury (Hg 0 ), oxidized mercury (Hg 2+ ), and particle mercury (H g P ) [2]. Among them, Hg 2+ and H g P can be easily removed by wet flue gas desulfurization (WFGD) and electrostatic precipitator [3].…”