Preparation And Properties Of Bulk Nanobubbles By Mixing Alcohol And Water

In the past ten years,the research and development of nanobubbles has developed rapidly and has become a research hotspot in the field of interface science.Nanobubbles can be widely used in environmental,biological,pharmaceutical and health care fields,such as surface coating and cleaning,new energy systems,medical ultrasound imaging and bubble drug delivery,and promotion of animal and plant growth.The basic research of bulk nanobubbles will have important guiding significance for its application in more fields.The research content of this paper mainly includes three aspects:First,the bulk nanobubbles with different properties were prepared by changing the mixing mode of alcohol and water.The size and unit volume of the bubble were characterized by the Nanoparticle Tracking Analysis system（NTA）.The particle size of the nanobubble was uniform,and the number of units per volume was above 10⁹particles·mL^-1.It was found that the injection speed of ethanol in the vertical upward static injection dispersion method was the main disturbance factor,and should be controlled within the range of 0.17 mL·min^-10.50 mL·min^-1 under the experimental conditions.The stirring speed of the water in the downward stirring and injection dispersion method was the main disturbance factor,and should be controlled at 100r·min^-1 under the experimental conditions.Second,the stability of bulk nanobubbles in alcohol-water mixtures had been studied,which influencing factors were temperature,pressure,dissolved oxygen and mechanical disturbances.The stability of nanobubbles was measured by the change in bubble size and number of bubbles per unit volume.In addition,the amount of dissolved oxygen in ethanol was estimated.The fluorescence emission spectrum showed that it had fluorescence emission at 335 nm.It was preliminarily determined that there were special hydrogen bond structures around the nanobubbles.These hydrogen bond structures may be responsible for the stable existence of bulk nanobubbles.Third,ethanol-water mixture containing bulk nanobubbles was applied to seed germination and surface cleaning.The ethanol-water mixture containing nanobubbles had a certain promoting effect on the germination of mung bean,red bean and lettuce seeds,especially for legume seeds.Comparing the cleaning effect of pure water and ethanol-water mixture without bulk nanobubbles on the glass flakes adhered by sodium oleate,the cleaning effect containing the bulk nanobubbles was better,and the residual amount of sodium oleate was less.