Fabrication of porous ceramic buoys (Ⅰ): preparation of porous ceramic beads for buoy manufacturing

Abstract This study presents the fabrication of porous ceramic buoys as an eco-friendly alternative to conventional expanded polystyrene (EPS) buoys, which are a major source of marine microplastics. Porous ceramic beads were synthesized using soda-lime glass waste as the base material through a foaming process involving a carbon-based blowing agent and CaCO₃. The optimized conditions—particle size below 25 μm, preheating at 600 °C, and foaming at 820–850 °C—produced lightweight beads with a bulk density of approximately 0.2 g cm⁻³. These beads were consolidated with white cement to form 40 L-class ceramic buoys exhibiting a buoyancy of 15 kgf and stable floating performance for more than 60 days. The results demonstrate that porous ceramic buoys not only achieve sufficient buoyancy and mechanical integrity but also offer a sustainable solution that can fundamentally mitigate marine microplastic pollution. Graphical abstract