Fabrication of amorphous carbon-based zinc oxide for efficient capture of intact Microcystis aeruginosa: Lysis in sedimentation process

The membrane integrity of harmful algae remains a major challenge for the safe and effective control of cyanobacterial blooms in drinking water sources. In this study, we used novel amorphous carbon-based ZnO (C@ZnO) nanoparticles to efficiently remove intact Microcystis aeruginosa cells. Different carbon-based ZnO composites were compared and characterized using XRD, Raman spectra , SEM, TEM, EDS, XPS and N 2 adsorption/desorption. The results revealed that a high cyanobacterial cell capture efficiency was obtained by C@ZnO nanoparticles without damaging membrane integrity. The removal efficiency for cell density, OD680, and chlorophyll-a reached 98.4 ± 0.87%, 90.9 ± 1.04%, and 99.5 ± 0.39%, respectively, with the addition of 4.0 g L −1 C@ZnO in 19 min. The viability of algal cells was observed through K + release, dissolved organic carbon release, and extracellular organic matrices during the removal process, thereby revealing the integrity of the cell structure. The optimal conditions (ZnO quantity of 333.80 mg and C@ZnO dosage of 3.48 g L −1 ) were verified via response surface methodology . The intracellular organic matter was released on day 2, although the floc could effectively adsorb part of the algal organic matter (AOM) released. This study developed novel amorphous C@ZnO nanoparticles materials for rapidly capturing intact cyanobacterial blooms to avoid secondary pollution and rovided theoretical guidance that the sludge should be quickly treated during cell removal using C@ZnO.