Extraction of pomegranate peel tannins and flocculant for Microcystis aeruginosa removal

Cyanobacteria blooms have received increasing attention due to their role in causing serious economic losses and endangering human health, leading to illnesses or even death. Thus, their removal by effective means is very important. A new botanical flocculating agent, tannin, was prepared from pomegranate peel. The influence factor of pomegranate peel tannin on Microcystis aeruginosa removal, including volume fraction of acetone aqueous solution, ratios of material to solvent, extraction temperature, extraction time and the addition of pomegranate peel tannin, was also investigated to determine the best preparation condition. Under the optimal conditions, the removal efficiency of pomegranate peel tannin flocculant on M. aeruginosa cells was 94.22%, and the removal efficiency of the same concentration chemical tannin on M. aeruginosa cells was 95.95%. According to these results, tannin could effectively flocculate and remove M. aeruginosa cells.