Silica-Silver Nanocomposites as Regenerable Sorbents for Hg⁰Removal from Flue Gases

Abstract

Silica-silver nanocomposites (Ag-SBA-15) are a novel class of multifunctional materials with potential applications as sorbents, catalysts, sensors, and disinfectants. In this work, an innovative yet simple and robust method of depositing silver nanoparticles on a mesoporous silica (SBA-15) was developed. The synthesized Ag-SBA-15 was found to achieve a complete capture of Hg at temperatures up to 200 °C. Silver nanoparticles on the SBA-15 were shown to be the critical active sites for the capture of Hg by the Ag-Hg amalgamation mechanism. An Hg capture capacity as high as 13.2 mg·g was achieved by Ag(10)-SBA-15, which is much higher than that achievable by existing Ag-based sorbents and comparable with that achieved by commercial activated carbon. Even after exposure to more complex simulated flue gas flow for 1 h, the Ag(10)-SBA-15 could still achieve an Hg removal efficiency as high as 91.6% with a Hg capture capacity of 457.3 μg·g. More importantly, the spent sorbent could be effectively regenerated and reused without noticeable performance degradation over five cycles. The excellent Hg removal efficiency combined with a simple synthesis procedure, strong tolerance to complex flue gas environment, great thermal stability, and outstanding regeneration capability make the Ag-SBA-15 a promising sorbent for practical applications to Hg capture from coal-fired flue gases.

Thioether-Functionalized Covalent Triazine Nanospheres: A Robust Adsorbent for Mercury Removal

“…IR spectrum was recorded on ATR mode by using Shimadzu FTIR Spectrometer. Solid-state 13 C CP-MAS NMR study was performed using a Bruker Advanced II spectrometer at 500 MHz with a MAS frequency of 8 kHz. Ultra-High resolution transmission electron microscopic (FEG-TEM) images were recorded in a JEOL JEM 2010 transmission electron microscope with operating voltage 200 kV equipped with a FEG.…”

“…The final solid was air-dried to obtain 85% pure product. 1 H NMR (400 MHz, CDCl 3 ) δ = 3.4 (s, 8 H); 13 C NMR (100 MHz, CDCl 3 /DMSO-d 6 ) δ = 134.17, 113. 21, 112.55, 28.43.…”

“…Several strategies have been developed over the years to reduce the concentration of toxic mercury. The popular processes for the Hg­(II) removal include complexation by reduced sulfur-containing ligands, membrane filtration, coagulation, adsorption, − chemical reduction, etc. Compared with other traditional separation technologies, adsorption is considered as the best technique due to the simplicity in setup and cost efficiency.…”

A novel nano-sized Co3O4@C catalyst derived from Co-MOF template for efficient Hg0 removal at low temperatures with outstanding SO2 resistance

“…(Bisson and Xu, 2015;Xu et al, 2018) Activated carbon can adsorb Hg 0 , but its low efficiency leads to high operation costs. (Cao et al, 2017) Therefore, the desire for more efficient and low-cost Hg 0 removal agents has focused research on catalysts.…”

Effect of Molybdenum on the Activity Temperature Enlarging of Mn-Based Catalyst for Mercury Oxidation

“…However, Hg 0 is difficult to capture by existing air pollution control devices due to its water insolubility and volatility. In the past 20 years, the methods of mercury removal, such as adsorption by sorbents [6,7] and oxidization by oxidants [8] or catalysts [9,10], have been widely investigated. Catalytic oxidation of Hg 0 was in the spotlight when the selective catalytic reduction (SCR) system in coal-fired power plants was found to be beneficial for elemental mercury oxidation [11,12].…”