A Study of Dissolved Gas Dynamics in Mixed Stream Electrolyzed Water

Abstract

Supersaturated hydrogen and oxygen solutions of pH-neutral tap water were created through electrolysis and subsequently blended back together. The blended solution was monitored as a function of time with dissolved gas meters and time-lapse photography. While the pH of the blended anodic and cathodic electrolysis streams returned to neutral pH within seconds, the blended solution was observed to retain significantly elevated dissolved gas concentrations on a timescale of hours. The analysis of dynamic bubble formation along the surfaces of the container, along with dissolved gas measurements, indicates that exsolution of dissolved hydrogen gas takes place on a very similar timescale. The measured total mass balance of gas produced electrolytically suggests that while a significant fraction of gas is exsoluted immediately before mixing of the anodic and cathodic streams, there are dissolved gases that take hours to exsolute completely from an undisturbed solution. Additionally, these signatures were studied as a function of electrolysis current.

Physics of Electrolytic Gas Evolution

“…Electrolytic gas evolution has been an interesting field for researchers and great progress has been achieved, but there are still challenging questions to be answered [83][84][85][86][87][88][89][90][91][92][93]. The majority of the studies have focused on miniature or micrometer-sized bubbles that are formed at the electrodes' surface and subsequently detach from it.…”

Electrosynthesis of hydrogen peroxide sustained by anodic oxygen evolution in a flow-through reactor

“…Furthermore, the dependence of the reactor performance on the flow rate also confirms that reaction (1) is mass-transport controlled, i.e., it is a function of the arrival of the dissolved O2 and the protons to the RVC cathode surface [15,17]. Not all the O2 evolving at the anode via reaction ( 2) is completed dissolved [30], which is a drawback because O 2 in gas form is not adequate to be reduced. However, RVC is a suitable material, since its porous structure can act as a gas diffusor that breaks the gas bubbles and yields smaller microbubbles that can be finally dissolved to undergo the cathodic reduction [17,28].…”