2.6.1 Determination method
See Supporting Information for the determination of microbubble size and microbubble-algal size. The content of chlorophyll a was determined by spectrophotometry.
Algal recovery (%) = (C1-C2) /C1*100
C1: Chla concentration before air flotation (since the ratio of algal water to dissolved air water is 1:2, the Chla concentration before air flotation is 1/3 of the Chla concentration of the original water sample); C2: Chla concentration after air flotation.