High Gravity-Enhanced In Situ Goethite-Catalyzed Alkaline H₂O₂ Systems for Nitric Oxide Removal in a Rotating Packed Bed: Mass-Transfer and Reaction Mechanism

Abstract

It is a challenge to maintain Fenton's oxidizability under alkaline conditions to efficiently oxidize nitric oxide (NO). Here, we find that an efficient catalyst goethite (α-FeOOH) to generate • OH is formed in an alkaline Fenton system and propose an in situ reactive oxygen species (ROS, hydroxyl radical ( • OH) and hydroperoxyl anion ( − OOH)) utilization mechanism in the high-gravity-enhanced α-FeOOH-catalyzed oxidation of NO within a rotating packed bed (RPB). A mathematical model is derived to elucidate the mechanism and evaluate the synergistic effect of ROS. The simulation results show that the generation and utilization sites of • OH gradually overlap in the liquid film with the increase in rotating speed. Additionally, the formation and properties of α-FeOOH are characterized to show its high dispersity in the RPB. Based on the mechanism, an in situ HiGee-AOP NO removal process is developed. Experimentally, the NO removal efficiency of the process can exceed 95% under optimal conditions.

Intensified ClO2 Generation/Utilization Mechanism for the High-Gravity SO2/NOx Removal Process within a Rotating Packed Bed

“…20 This model captures the NO absorption behavior by − OOH, which has prediction accuracy of around 10%. Lu et al presented a model evaluating the intensified mass-transfer mechanism of HGFR, 21 which has prediction accuracy of around 20%. However, these models only consider the mass-transfer resistance of the liquid film; the effect of the gas film is neglected.…”