Study on Fixed Salt Removal Effect by Fine Bubbles

Abstract

In recent years, it has become clear that 1 μm or less sized fine air bubbles have different properties from those of mm or cm sized air bubbles. This study examined the effect of fine bubbles on the removal of salt fixed in the gap of aluminum plate as a verification of cleaning action by fine bubbles. As a result, it was confirmed that the removal effect of fixed salt is higher in fine bubble water than in control water, and that the degree of effect depends on the concentration of fine bubbles. It was also confirmed that less than 1 μm sized ultrafine bubble water has a higher removal effect than the control water. As a mechanism of removing fixed salt, it is conceivable that peeling effect, like lifting up part of fixed salt, in which fine bubbles are dissolved by pressure change around the fixed salt to become supersaturated, causing further bubbling around there, and/or physical collision effect of microbubbles. In addition, it was confirmed that the removal effect of a system in which fine bubbles were regularly introduced was much higher than the one that does not introduce fine bubbles regularly. In addition, even when the gap between fixed salt and aluminum plate was narrowed, the superiority of fine bubble cleaning was confirmed.

Pretreatment with fine bubbles for effective zinc ion precipitation and removal from zinc electroplating wastewater

“…This effect accelerates the cleaning of solid salts adhered to a plate. [ 27 ] These effects may have influenced the cleaning of the oil in this study; however, their contributions are difficult to determine. The results indicate that the FB concentration affects the oil cleaning effectiveness.…”

Effective Purification of Eutrophic Wastewater from the Beverage Industry by Microbubbles

“…Each container held 30 L of test solution which was circulated by a water pump, with the substrate liquid flowing in 15 cm above the bottom of the container and out 5 cm above the bottom. Microbubbles (MiBs) were generated via a gas-liquid shear system (FB-S15AI, Sakamoto-Giken Inc., Nankoku, Kochi, Japan) in which a gas shear field was created by swirling a liquid [41]. Output from the MiB generator was incorporated into the water circulation line of each container.…”

“…Air MiBs with an average diameter of 50 µm were generated in this way and supplied to the systems (Figure 2). Details of the determination of the distribution of bubble sizes are as described by Mikasa et al [41]. To compare the effect of MiBs versus macrobubbles (MaBs), MaBs were generated by an aquarium air pump (Super Silent Air Pump Pulse 4000, Kotobuki, Nara, Japan).…”