Spontaneous Microalgae Dewatering Directed by Retrievable, Recyclable, and Reusable Nanoparticle-Pinched Polymer Brushes

Selective capture and separation of solution-borne planktonic cells is a ubiquitous challenge in diverse fields ranging from biofilm mitigation, cancer diagnostics, water treatment, to microalgae biofuels. Microalgae are promising feedstocks for carbon-neutral biofuels that will alleviate our repentant dependency on fossil fuels, but current technologies for dewatering microalgae add a prohibitive cost to the final products. We report here a nanoparticle-pinched polymer brush (NPPB) design that transforms ordinary polymer flocculants into super-coagulants by mimicking bacterial outer membrane vesicles in promoting bacteria coaggregation. Importantly, the NPPBs are retrievable via cost-effective magnetophoretic separation, recyclable after algae oil extraction and residual biomass removal, and reusable for repeated cycles of operations that significantly reduces the endless materials cost of flocculants and their potential contamination of downstream processes and the environment. Using DLVO and self-consi...