Efficient harvesting of wet blue-green microalgal biomass by two-aminoclay [AC]-mixture systems

[Display omitted] •Flocculation-based harvesting (precipitation) method as an alternative.•Mixtures of [MgAC] and [CeAC] to harvest cyanobacteria.•Compact networks of the ACs mixture for efficient bridging between microalgal cells.•Evolutions of MgOx and CeOx nanoparticles on the biochar matrixes.•Utilization of environmental adsorbents and bioenergy catalysts. Blue-green microalgal blooms have been caused concerns about environmental problems and human-health dangers. For removal of such cyanobacteria, many mechanical and chemical treatments have been trialled. Among various technologies, the flocculation-based harvesting (precipitation) method can be an alternative if the problem of the low yield of recovered biomass at low concentrations of cyanobacteria is solved. In the present study, it was utilized mixtures of magnesium aminoclay [MgAC] and cerium aminoclay [CeAC] with different particle sizes to harvest cyanobacteria feedstocks with ∼100% efficiency within 1h by ten-fold lower loading of ACs compared with single treatments of [MgAC] or [CeAC]. This success was owed to the compact networks of the different-sized-ACs mixture for efficient bridging between microalgal cells. In order to determine the usage potential of biomass harvested with AC, the mass was heat treated under the reduction condition. This system is expected to be profitably utilizable in adsorbents and catalysts.