Improving oxidation efficiency through plasma coupled thin film processing

Abstract

A continuous flow vortex fluidic device (VFD) with a non-thermal plasma generated above a dynamic thin liquid film created in a rapidly rotating tube is effective in the oxidation of methylene blue. The VFD allows for the control of the film thickness by adjusting the rotational speed, and through this capability we demonstrate that reducing the film thickness enhances the ability for active oxidizing species produced in the plasma to process material contained within the film. These efficiencies inherent in the VFD technology have general applicability to flux-driven chemical processing, such as photo-and electrochemical transformations.

Neutron imaging and modelling inclined vortex driven thin films

“…The model takes into account gravity and the centripetal force, and is consistent with previous derivations for Liquid Mirror Telescopes, which use the reflective paraboloid produced by mercury in a rotating container as an astronomical telescope 11,12 , as well as other work performed investigating the film shape 13 . The model is further detailed in the Supplementary Information, with the resultant equation for the film heightwhich can be rearranged in the form for calculating the film thickness,Here, r is the radial distance from the rotation axis of the tube and z is the distance along this axis above the base of the tube.…”

Electron-impact electronic-state excitation of para-benzoquinone

“…[40][41][42] These computational simulations are important in extending dosimetry to the quantification of induced chemical processes within nanosized volumes and building predictive plasma models that can be used to optimise plasma-based technologies for medical therapies 43,44 or novel chemical processing. [45][46][47][48][49][50] The present investigation continues this rich vein of research, seeking to contribute to the cross section data base 51 that will ultimately be employed to study the behaviour of electrons in pBQbased swarm measurements, similar to what we undertook in Ref. 52, and to also simulate charged-particle track behaviour 53 in pBQ.…”

A Microfluidic Atmospheric-Pressure Plasma Reactor for Water Treatment

“…4 is 0.088 s −1 , 0.11 s −1 and 0.13 s −1 for air, argon and oxygen respectively. This model was used to show that using the microfluidic device allows high degradation efficacy to be achieved, with residence times in the order of seconds rather than the minutes or hours that have been reported in numerous studies [34][35][36][37]45]. The results show that maximising residence time leads to enhanced degradation.…”

“…These conditions produced a thin film of liquid on the walls of the microchannels, enabling control of two key parameters for PWT: liquid film thickness and residence time. In general, the microfluidic device operated with liquid films on the order of micrometres and residence times of seconds, compared to batch type plasma reactors reported in literature with residence times in the order of several minutes or hours and film thicknesses of several millimetres [12,[34][35][36][37]. The mean residence time of the solution in two-phase annular flow along the plasma discharge zone was estimated as the ratio of the inner volume of the reactor to the volumetric flow rate [38], ranging from 3 to 9 s and 1 to 5 s in 100 μm and 50 μm channel depths, respectively.…”