Active Treatment of Oily Emulsion Wastewater by Bio-Derived Tubular Micromotors

Ziming Wang; Mengyin Tan; Hong Wang

Abstract

The treatment of oil-in-water emulsion wastewater remains a challenge due to the presence of finely dispersed oil droplets stabilized by surfactants. Herein, an active demulsifier based on the bio-templated tubular micromotor was designed. The hollow architecture of naturally abundant kapok fibers facilitates generation of micro/nanobubbles catalyzed by MnO₂ immobilized on the surface and enables efficient propulsion of the tubular structure in H₂O₂ solution, while the integrated Fe₃O₄ nanoparticles endow the micromotors with facile magnetic recyclability. To enhance interaction with oil droplets, a polydopamine interlayer is introduced for subsequent fluorinated thiol grafting. The tailored surface properties of micromotors together with the bubble-driven propulsion greatly facilitated the demulsification process. Comparison between the static control experiments and the self-propelled micromotors corroborated the contribution of bubble propulsion. Under optimized conditions, a demulsification efficiency of 98.19% was achieved within 27 min, markedly superior to that obtained in the static system. The self-propelled micromotors effectively accelerated emulsion destabilization through autonomous locomotion and bubble-assisted flotation effects. This proposed micromotor provides a promising platform for the remediation of emulsified oily wastewater.

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