4 research outputs found
An integrated microfluidic chip for generation and transfer of reactive species using gas plasma
Reactive species produced by atmospheric pressure
plasma (APP) are useful in many applications including disinfection, pretreatment,
catalysis, detection and chemical synthesis. Most highly reactive species produced
by plasma, such as ·OH, 1O2 and
, are
short-lived; therefore, in-situ generation is essential to transfer plasma
products to the liquid phase efficiently. A novel microfluidic device that
generates a dielectric barrier discharge (DBD) plasma at the gas-liquid
interface and disperses the reactive species generated using microbubbles of ca.
200 µm in diameter has been developed and tested. As the bubble size affects the
mass transfer performance of the device, the effect of operating parameters and
plasma discharge on generated bubbles size has been studied. The mass transfer
performance of the device was evaluated by transferring the reactive species generated
to an aqueous solution containing dye and measuring percentage degradation of
the dye. Monodisperse microbubbles (polydispersity index between 2 - 7%) were
generated under all examined conditions but for gas flow rate exceeding a
critical value, a secondary break-up event occurred after bubble formation leading
to multiple monodisperse bubble populations. The generated microbubble size
increased by up to ~ 8% when the device was operated with the gas plasma in the
dispersed phase compared to the case without the plasma due to thermal
expansion of the feed gas. At the optimal operating conditions, initial dye
concentration was reduced by ~60% in a single pass with a residence time of 5-10
s. This microfluidic chip has the potential to play a significant role in
lab-on-a-chip devices where highly reactive species are essential for the
process. </p
Microfluidic plasma reactor for organic synthesis
Microfluidic plasma reactor for organic synthesi
Epoxidation of trans-stilbene in a microfluidic plasma reactor
Novel organic synthesis routes that circumvent the need for a catalyst and reduce unwanted by-products are highly sought
by industry. A novel microfluidic plasma reactor that generates a dielectric barrier discharge (DBD) plasma in the vicinity
of the gas-liquid interface and facilitate a chemical reaction at the interface of microbubbles has been used for transstilbene epoxidation. Three different operating strategies were implemented to optimise the transfer of species selectivity:
single pass, multi-pass and continuous recirculation. The effect of initial trans-stilbene concentration, oxygen content in
the feed gas mixture and reaction time on the epoxide formation was studied to optimise the chemical reaction. The
optimum operating conditions were found to be short bubble-liquid contact times (~2 s) with frequent exposure to freshly
generated microbubbles containing reactive species by continuous liquid recirculation, and under these conditions the
overall epoxide yield was ~94% with an overall epoxide selectivity of 10:1
Supplementary Information Files for 'An integrated microfluidic chip for generation and transfer of reactive species using gas plasma'
Supplementary Information Files for 'An integrated microfluidic chip for generation and transfer of reactive species using gas plasma'Abstract:Reactive species produced by atmospheric pressure plasma (APP) are useful in many applications including disinfection, pretreatment, catalysis, detection and chemical synthesis. Most highly reactive species produced by plasma, such as ·OH, 1O2 and , are short-lived; therefore, in-situ generation is essential to transfer plasma products to the liquid phase efficiently. A novel microfluidic device that generates a dielectric barrier discharge (DBD) plasma at the gas-liquid interface and disperses the reactive species generated using microbubbles of ca. 200 µm in diameter has been developed and tested. As the bubble size affects the mass transfer performance of the device, the effect of operating parameters and plasma discharge on generated bubbles size has been studied. The mass transfer performance of the device was evaluated by transferring the reactive species generated to an aqueous solution containing dye and measuring percentage degradation of the dye. Monodisperse microbubbles (polydispersity index between 2 - 7%) were generated under all examined conditions but for gas flow rate exceeding a critical value, a secondary break-up event occurred after bubble formation leading to multiple monodisperse bubble populations. The generated microbubble size increased by up to ~ 8% when the device was operated with the gas plasma in the dispersed phase compared to the case without the plasma due to thermal expansion of the feed gas. At the optimal operating conditions, initial dye concentration was reduced by ~60% in a single pass with a residence time of 5-10 s. This microfluidic chip has the potential to play a significant role in lab-on-a-chip devices where highly reactive species are essential for the process.</div