Wastewater
remediation toward heavy metal pollutants has attracted
considerable attention, and various adsorption-based materials were
employed in recent years. However, it is still challenging to explore
low-cost and high-efficient adsorbents with superior removal performance,
nontoxicity, flexible operation, and good reusability. Herein, Fe3O4- and MnO2-loaded biohybrid magnetic
helical microrobots (BMHMs) based on Spirulina cells
were presented for the first time, and their performance on Pb(II)
removal was studied in detail. Intracellular synthesis of Fe3O4 and MnO2 nanoparticles into Spirulina cells was successively conducted to obtain the BMHMs with superparamagnetism
and high surface activity. The BMHMs could be flexibly propelled under
magnetic actuation, and collective cork-screw spinning was performed
to enhance fluidic diffusion with intensive adsorption. Rapid and
significant removal of Pb(II) in wastewater was achieved using the
swarming microrobots, and a high adsorption capacity could be reached
at 245.1 mg/g. Moreover, the BMHMs could be cyclically reutilized
after simple regeneration, and good specificity toward Pb(II) was
verified. The adsorption mechanism was further studied, which revealed
that the pseudo-second-order kinetics dominated in the adsorption
process, and the Langmuir isothermal model also fitted the experimental
results well. The intriguing properties of the BMHMs enable them to
be versatile platforms with significant potentials in wastewater remediation.