Lab- and pilot-scale wet scrubber study on the redox-mediated simultaneous removal of NO and SO using a CaCO-based slurry with KI as a redox catalyst.

This study presents a novel approach that integrates ozone-driven chemical oxidation to convert NO into soluble NO, followed by the simultaneous absorption of NO and SO into a CaCO-based slurry using the redox catalyst potassium iodide (KI). Using cyclic voltammetry, we demonstrate the redox properties of the I/2I couple, which facilitates NO reduction into soluble NO and catalyst regeneration through sulfite (SO)-driven reduction, thus establishing a closed catalytic cycle within the components of flue gas. In lab-scale wet-scrubbing tests, we explore the effect of various operational parameters (i.

Gas-diffusion-electrode based direct electro-stripping system for gaseous ammonia recovery from livestock wastewater.

Livestock wastewater (LW) typically contains a substantial amount of NH that can potentially be recovered and used in fertilizers or chemicals. In an attempt to recover NH from LW, a novel electrochemical approach using a gas diffusion electrode (GDE) was developed and its efficacy was demonstrated in this study. The GDE-based electrochemical device, when operated at an air-flow rate of 20 mL/min, was free of back-diffusion flux, which is a fatal drawback of any membrane-based NH separation approach.

Electrochemical ammonia accumulation and recovery from ammonia-rich livestock wastewater.

High levels of ammonia inhibit microbial activities and lead to process instability of traditional wastewater treatment. Nitrogen recovery via ammonia stripping is the best developed method, but this approach requires large amounts of alkaline chemicals and substantial energy for stripping. In this study, we designed a simple electrochemical system that allows the facile accumulation of a neutral species of ammonia (NH), resulting in much lower overall stripping costs.