Investigating the Efficiency of Magnetized Biopolymer Beads in Extracting Small Plastics from Low-Flow Water Systems

Small kinds of plastics, such as micro- or macroplastics, are common environmental pollutants that threaten ecosystems and human health, with an estimated 10–40 million metric tons entering the environment annually and projected to double by 2040 (Thompson et al., 2024). Due to their synthetic and non-degradable nature, small plastics persist in aquatic environments and accumulate in food chains, posing risks of endocrine disruption, inflammation, and bioaccumulation of toxic chemicals (Ziani et al., 2023). This study investigates whether magnetized biopolymer beads, sodium alginate beads embedded with iron-oxide nanoparticles, can serve as a low-cost and scalable method for extracting small plastics from low-flow water systems. A quasi-experimental design was used to test four bead concentrations (10, 20, 30, and 40 beads) in a simulated low-flow water system. Small plastic extraction efficiency was measured through filtration and manual particle counting, while bead stability was evaluated across eight reuse cycles. Results showed that extraction efficiency increased with bead concentration, rising from 0.33% with 10 beads to 7.67% with 40 beads. Statistical analysis indicated that only the increase from 10 beads to higher concentrations was significant (p = 0.019–0.001), while additional increases beyond 20 beads showed no statistically significant differences. The beads maintained magnetic responsiveness and structural integrity throughout repeated reuse cycles. These findings demonstrate that magnetized alginate beads can capture small plastics in low-flow water systems, confirming the concept's feasibility. However, the relatively low removal efficiency suggests that further improvements, such as surface modification or polymer functionalization, are necessary to enhance adsorption and support practical environmental applications.