Plasmonic Photothermal‐Assisted Marangoni Convection for Efficient Microplastic Removal

Microplastics (MPs) are an emerging pollutant with long‐term ecological and health risks, yet conventional removal methods often suffer from fouling, high cost, or secondary contamination. In this work, a plasmonic photothermal‐assisted convection reactor was developed to achieve efficient and membrane‐free microplastic capture. Simulations showed that hemispherical plasmonic nanostructures exhibited the highest heating performance, and the maximum temperature increased linearly with solar irradiation intensity. Parametric studies identified the optimal conditions for adhesion efficiency, including a plate spacing of 0.06 cm, a plate length of 0.04 cm, an inlet velocity of 0.35 m/s, and a particle size of 100–150 μm, under which adhesion exceeded 85%. When structural flexibility was introduced, elastic deformation enhanced local Marangoni shear and stabilized vortex structures, enabling comparable or higher adhesion efficiencies above 90% at much lower temperature differences. The analysis revealed that adhesion efficiency closely correlates with the recirculation area and vorticity integral, confirming that vortex stability and strength together govern particle trapping. These findings demonstrate that coupling plasmonic heating with thermoelastic flow control provides a scalable and energy‐efficient approach for solar‐driven removal of MPs from water.