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Title: HCOO − aq degradation in droplets by OH aq in an atmospheric pressure glow discharge

Plasmas in contact with liquids can degrade organic molecules in a solution, as reactive oxygen and nitrogen species produced in the plasma solvate into the liquid. Immersing small droplets (tens of microns in diameter) in the plasma can more rapidly activate the liquid compared to treating a large volume of liquid with a smaller surface-to-volume ratio. The interactions between a radio frequency glow discharge sustained in He/H2O and a water droplet containing formate (HCOOaq) immersed in and flowing through the plasma were modeled using a zero-dimensional global plasma chemistry model to investigate these activation processes. HCOOaqinteracts with OHaq, which is produced from the solvation of OH from the gas phase. The resulting HCOOaqconcentrations were benchmarked with previously reported experimental measurements. The diameter of the droplet, initial HCOOaqconcentration, and gas flow rate affect only the HCOOaqconcentration and OHaqdensity, leaving the OH density in the gas phase unaffected. Power deposition and gas mixture (e.g. percentage of H2O) change both the gas and liquid phase chemistry. A general trend was observed: during the first portion of droplet exposure to the plasma, OHaqprimarily consumes HCOOaq. However, O2aq, a byproduct of HCOOaqconsumption, consumes OHaqonce O2aqreaches a critically large density. Using HCOOaqas a surrogate for OHaq-sensitive contaminants, combinations of residence time, droplet diameter, water vapor density, and power will determine the optimum remediation strategy.

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Award ID(s):
1902878 2032604
Author(s) / Creator(s):
; ; ;
Publisher / Repository:
IOP Publishing
Date Published:
Journal Name:
Journal of Physics D: Applied Physics
Page Range / eLocation ID:
Article No. 285202
Medium: X
Sponsoring Org:
National Science Foundation
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