Effect of Mixed Nanobubble and Microbubble Liquids on the Washing Rate of Cloth in an Alternating Flow

Abstract

AbstractIt is well‐known that laundry waste water contributes to water pollution, and the need to reduce the amount of detergent used is widely recognized. Predominantly, research has focused on the washing effects of microbubbles and nanobubbles, and mechanical work was found to account for about 50 % of the washing effect on the cloth. In the present research, mixed nanobubble and microbubble water and four types of surfactants (including a commercial cleaning liquid) were investigated in an alternating flow system. The nanobubble water achieved a washing rate greater than that of ion‐exchanged water. However, the microbubble water had the same washing rate as ion‐exchanged water. Moreover, nanobubbles mixed with an aqueous solution of surfactant exhibited a washing rate that depended on the ionization of the surfactant: the mixture with nanobubbles and anionic surfactant exhibited a washing rate that was higher than that of aqueous anionic surfactant solution without nanobubbles. The surface tensions of nanobubble water and mixed nanobubble anionic surfactant were lower than those without nanobubble, respectively. Also, there was no advantage in mixed microbubble liquids. These results provide evidence of an enhanced washing effect by nanobubble mixtures in liquids.