Dielectric barrier discharge (DBD) has emerged in recent years as a highly promising technology for
advanced water treatment. Its efficacy stems from the generation of a rich reactive oxygen species
(ROS), which drive essential processes including chemical oxidation, microbial sterilization, and the
degradation of recalcitrant pollutants. Despite its potential, a fundamental mechanistic understanding
of DBD-based water treatment remains incomplete. Key knowledge gaps persist concerning the
formation pathways of ROS within the gas phase plasma, the complex physicochemical phenomena
governing their transfer across the dynamic plasma-liquid interface, reaction kinetics, and the reaction
within the aqueous phase. Addressing these gaps necessitates the development of a comprehensive,
predictive model that rigorously integrates plasma discharge physics, interfacial transport phenomena,
and detailed liquid-phase reaction chemistry. Such a physics-based framework is critical for
elucidating the underlying mechanisms and enabling the rational design and optimization of high
efficiency plasma reactors.
This PhD project aims to bridge this knowledge gap by developing and experimentally validating a
complex multiphysics simulation framework using COMSOL. The main objectives are:
– To simulate the non-equilibrium plasma chemistry within a DBD reactor operating in water,
predicting the formation kinetics and concentrations of key reactive species (e.g., ·OH, O₃,
H₂O₂).
– To model the dynamic processes governing the transfer of these ROS across the plasma-liquid
interface, incorporating effects of plasma filaments, gas-liquid hydrodynamics, and interfacial
reactions.
– To simulate the dissolution, diffusion, reaction kinetics, and evolution of ROS and their
reaction products within the aqueous phase.
The computational modelling will be tightly integrated with targeted experimental investigations to
ensure model fidelity. Experimental techniques will include:
– Optical Emission Spectroscopy (OES): For quantifying transient gas-phase species
concentrations.
– High-Speed/High-Resolution Imaging: To characterize plasma filament dynamics,
morphology, and interface interactions.
Liquid phase Chemical Analysis: Utilizing UV-Vis spectrophotometry, and potentially mass
spectrometry (MS), HPLC to identify and quantify stable reaction products (e.g., O3, H₂O₂) and
measure oxidant concentrations under varying conditions.
These experiments will provide essential data for calibrating kinetic parameters and rigorously
validating the simulation model across a range of operational parameters (applied voltage, frequency,
gas composition, flow rate).
By synergistically combining advanced multiphysics modelling with targeted experimental validation,
this project will deliver a deeper mechanistic understanding of the coupled interfacial physics and
chemistry in plasma-liquid systems for water treatment. A validated computational framework capable
of simulating DBD reactor performance under diverse operating conditions. Essential knowledge and
tools to guide the rational design, optimization, and future scale-up of DBD reactors for industrial
water treatment applications.