Experimental study of the effect of salinity and surfactant on mass transfer characteristics of oxygen micro-nano bubbles

The application of micro-nano bubbles (MNBs) in water treatment technology has been gaining more and more attention recently. In order to investigate the effect of salinity and surfactant on mass transfer characteristics of oxygen MNBs, a series of laboratory experiments conducted on oxygen MNBs water with different salinities and surfactant concentrations. The test results showed that two ranges obtained for oxygen MNBs size and the main parts were 0.026-0.172 μm and 1.635-6.540 μm. With the salinity of 0 g/L, the peak value of dissolved oxygen (DO) in oxygen MNBs water was 44.13 mg/L and the saturation time of DO was 11400 min. But when the salinity was 3 g/L, the peak value of DO increased by 7.68% and the saturation time of DO was extended by 9.32%. When the salinity was between 0 g/L and 2 g/L, the mass transfer efficiency of oxygen MNBs was adversely affected by salinity. In addition, sodium dodecyl benzene sulfonate (SDBS) reduced the peak value of DO and extended the saturation time of DO by changing the interface potential of oxygen MNBs.