Towards understanding plasma formation in liquid water via single bubble studies

Abstract

Plasma-in-water based technological approaches offer great potential to addressing a wide range of contaminants threatening the safety of freshwater reserves. Widespread application of plasma-based technologies, however require a better understanding of plasma formation processes in water and the nature of the plasma-driven chemistry in solution. In this paper, we survey the scope of the threat to freshwater via contamination from a variety of sources, the status of conventional treatment technologies, the promise of plasma-based water purification, and the pathway to understanding plasma formation in water through the study of single bubble breakdown physics. Plasma formation in bubbles lie at the heart of plasma formation in liquid water. We present findings from ongoing research at the University of Michigan aimed at understanding the nature of plasma formation in bubbles, which provides an avenue for not only understanding breakdown conditions, but also insight in reducing the magnitude of the breakdown voltage. These experiments also establish an approach to a standardized apparatus for the study of plasma discharges in bubbles. We also discuss approaches to controlling plasma-induced chemistry in liquid water.

Discharge phenomena in a cavitation bubble induced by liquid-phase laser ablation

“…This is completely different from the experimental results reported by Foster and Gucker [26,27]. They observed the discharge in a cavitation bubble produced by applying an ultrasonic power to water.…”

“…The experimental results suggest that the cavitation bubble is conductive and it has free charges. This may be a unique feature of the cavitation bubble induced by liquid-phase laser ablation, since the deformation of the cavitation bubble is not observed when it is produced by an ultrasonic power [26,27]. Since it has been found that the growth field of nanoparticles in liquid-phase laser ablation is the inside of the cavitation bubble [36][37][38][39][40], the present experimental results may explain the origin of the high zeta potential of the colloidal solution synthesized by liquid-phase laser ablation.…”

“…However, just depositing the power into the liquid has difficulty in fundamental investigations on discharge mechanisms in bubbles, since the thermal production of bubbles occurs randomly. A bubble produced at a fixed position and a fixed timing is useful to carry out the efficient investigation on the discharge phenomena in a bubble [24][25][26][27].…”

Liquid Phase Pulsed Discharge as a Chemical-Free Green Method for α-Alumina Synthesis

“…Negative charge starts to build up and results in arc discharges which penetrate through and destruct the aluminum flakes (2) . Hydroxide and aluminum ions are then bonded to form Al(OH) 3 with hydrogen bubbles being liberated (3) . No sign of erosion‐corrosion was observed on the electrodes after reactions (data not shown).…”

“…[41] Hydroxide and aluminum ions are then bonded to form Al(OH) 3 with hydrogen bubbles being liberated (3). [42] No sign of erosion-corrosion was observed on the electrodes after reactions (data not shown). FE-SEM and EDS analysis result shows that submicron sized Al(OH) 3 crystallite with high purity is synthesized (Figure 2).…”