Toward a Sustainable Solution for Ocean Cleanup: Reusable Ferrofluid System for Microplastic Extraction and Separation
Roy Seoyul Son
Hong Kong International School, Tai Tam, Hong Kong SAR
Publication date: November 20, 2025
Hong Kong International School, Tai Tam, Hong Kong SAR
Publication date: November 20, 2025
DOI: http://doi.org/10.34614/JIYRC2025II52
ABSTRACT
Microplastic pollution poses a critical global challenge due to its persistence, toxicity, and ability to enter marine food webs. Existing separation methods suffer from inefficiencies, environmental risks, or limited scalability. This study explores a reusable ferrofluid-based system for sustainable microplastic removal and regeneration. Dose–response tests revealed optimal capture efficiency (~95%) at ~300 µL ferrofluid per 50 mL water, with a linear binding capacity of ~2.0 mg plastic per µL under non-limiting conditions. Comparable results in seawater without ethanol confirmed applicability in realistic marine environments. Reusability assays demonstrated that canola oil preserved >90% removal efficiency across five cycles, while untreated ferrofluid rapidly lost performance. Recovery trials showed heat-drying retained ~92% ferrofluid mass and ~95% magnetic responsiveness, outperforming detergent rinses. Fluorescence microscopy further verified that canola oil reduced plastic–ferrofluid co-localization from ~82% to ~21%, enabling clean regeneration. Together, these findings establish ferrofluid as a cost-effective, scalable, and sustainable approach for ocean cleanup.
Microplastic pollution poses a critical global challenge due to its persistence, toxicity, and ability to enter marine food webs. Existing separation methods suffer from inefficiencies, environmental risks, or limited scalability. This study explores a reusable ferrofluid-based system for sustainable microplastic removal and regeneration. Dose–response tests revealed optimal capture efficiency (~95%) at ~300 µL ferrofluid per 50 mL water, with a linear binding capacity of ~2.0 mg plastic per µL under non-limiting conditions. Comparable results in seawater without ethanol confirmed applicability in realistic marine environments. Reusability assays demonstrated that canola oil preserved >90% removal efficiency across five cycles, while untreated ferrofluid rapidly lost performance. Recovery trials showed heat-drying retained ~92% ferrofluid mass and ~95% magnetic responsiveness, outperforming detergent rinses. Fluorescence microscopy further verified that canola oil reduced plastic–ferrofluid co-localization from ~82% to ~21%, enabling clean regeneration. Together, these findings establish ferrofluid as a cost-effective, scalable, and sustainable approach for ocean cleanup.
