optimization of ferrofluid based microplastics removal: a case study of kibangu river, tanzania

Microplastics (mps) pollution has become a major global environmental concern, significantly affecting aquatic ecosystems. this study assessed mp contamination in the kibangu river and developed a novel ferrofluid-based method for mp removal. mp abundance in the river ranges from 9 to 21 particles/l, with an average of 15 particles/l. the highest abundance was recorded at the riverside interchange (21 particles/l), while nida textiles exhibited the lowest (9 particles/l). optimization experiments identified 3.2 g/l ferrofluid concentration and a 25-minute contact time as the most effective conditions for removal, beyond which no significant improvement was observed. removal efficiency varied with mp size and polymer type; smaller particles (38 µm) exhibited higher removal rates due to their larger surface area to volume ratio. polyethylene (pe) achieved a 93% removal rate, while polypropylene (pp) reached 88%. fresh vegetable and castor oils significantly enhanced ferrofluid performance at lower concentrations (1–1.5 ml), with fresh vegetable oil showing the highest efficiency. however, higher oil concentrations and used oils were less effective. these findings underscore the importance of optimizing oil selection and operational parameters to enhance mp removal. this study presents a scalable, environmentally friendly solution to mitigate mp pollution, providing a foundation for further research and potential applications in water treatment and environmental management.