NOx attenuation in flue gas by •OH/SO4•--based advanced oxidation processes

Advanced Oxidant Process with Fe(II)-Catalyzed Alkaline H2O2 Systems for Highly Efficient Concurrent Scavenging of NO and SO2 in High Gravitational Fields

“…A significant BMPO− OH adduct signal was observed in the H 2 O 2 solution to which FeSO 4 was added. The characteristic peaks (1:2:2:1) were determined to be the spectrum shape of the BMPO−OH adduct because constants of hyperfine splitting of N and H atom (aN = aH = 15 Gs) were consistent with data in the literature, 33 indicating that ȮH has been produced. Furthermore, a weak BMPO−OH adduct signal appears in the alkaline H 2 O 2 solution, indicating that OH − prompted ̇OH generation.…”

“…RPB, also known as a high gravity (HiGee) reactor, is an effective intensification technology featuring efficient mass transfer by allowing for rapid liquid-film renewal. − Because of the high-speed rotation of the packing in RPB, the shearing and breaking effects on droplets and liquid films could enhance liquid–liquid micromixing, , gas–liquid mass-transfer areas, and high-frequency liquid-film renewal . The enlarged mass-transfer areas increase the potential of NO and ROS reactions on the surface of the liquid film . High-frequency liquid-film renewal dramatically increases the concentration gradient of ROS in the liquid film, causing ROS to diffuse from the liquid bulk to the phase interface. , Therefore, ROS may be utilized while being produced in the RPB, resulting in increased ROS utilization and efficient NO and SO 2 removal.…”

“…The enlarged mass-transfer areas increase the potential of NO and ROS reactions on the surface of the liquid film . High-frequency liquid-film renewal dramatically increases the concentration gradient of ROS in the liquid film, causing ROS to diffuse from the liquid bulk to the phase interface. , Therefore, ROS may be utilized while being produced in the RPB, resulting in increased ROS utilization and efficient NO and SO 2 removal. Zheng et al had previously utilized HiGee-enhanced AOP to remove NO via ̇OH from a typical Fenton reagent and achieved considerable NO removal.…”

Mechanism and Kinetic Study of Cyclodextrin Use to Facilitate NO2 Absorption in Sulfite Solutions

“…NO comprises 90% of NO x compounds at least in flue gases, resists aqueous absorption due to its poor dissolution behavior in water (Henry’s law constants at T θ , H cp = 1.9 × 10 –5 mol·m –3 ·Pa –1 ) . In contrast, high-valence NO x always possess satisfactory water solubility, for example, NO 2 , N 2 O 4 , NO 3 , and N 2 O 5 ( H cp of 1.4 × 10 –4 . , 4 × 10 –2 . , 8 × 10 –2 , and 2.1 × 10 –2 , respectively).…”

“…4 Furthermore, WFGD processes always realize the favorable desulfurization in treating flue gases that contain high concentrations of sulfur species. 5 NO comprises 90% of NO x compounds at least in flue gases, 6 resists aqueous absorption due to its poor dissolution behavior in water (Henry's law constants at T θ , H cp = 1.9 × 10 −5 mol•m −3 •Pa −1 ). 7 In contrast, high-valence NO x always possess satisfactory water solubility, for example, NO 2 , N 2 O 4 , NO 3 , and N 2 O 5 (H cp of 1.4 × 10 −4 .…”