Preparation of magnetic Janus microparticles for the rapid removal of microplastics from water

The continuous spread of microplastics in aquatic environments poses a growing concern and a potential risk to human health. To address this concern, this paper presents a novel approach using magnetic Janus microparticles (MJMs) synthesized via a modified Pickering emulsion method with aminated Fe₃O₄@SiO₂ as the raw material. The effectiveness of these MJMs in removing polystyrene (PS) and polyethylene (PE) microplastics from water was investigated. Paraffin was employed as the masking agent, while N-Octadecylphosphosphonic acid (PAC₁₈) was used as the graft material for MJM preparation. The resulting particles exhibited a distinctive asymmetric flower-shaped structure on the surface, which was confirmed through various analytical techniques including FTIR, TGA, SEM, and water phase contact angle analysis. The MJMs demonstrated exceptional efficiency in adsorbing microplastics. With a microplastic suspension concentration of 2 mg/mL and an adsorbent dosage of 1 mg/mL, the MJMs can attain removal efficiencies of 92.08 % for PS and 60.67 % for PE in just 20 min of contact time. The effectiveness of the adsorption process was attributed to several factors, including hydrophobic interactions, cation-π interactions, electrostatic attraction, and the efficient dispersion of particles in water, as revealed by size distribution and zeta potential analysis. Additionally, kinetic and thermodynamic studies confirmed the remarkable adsorption rate and capacity of the MJMs (0.759 min^-1 and 2.72 mg/mg for PS, 0.539 min^-1 and 2.42 mg/mg for PE), highlighting their potential as a promising method for rapidly removing microplastics from water. This work provides valuable insights into the development of effective strategies for addressing microplastic pollution in aquatic environments.