Biofluorescence of Mussel Shells and its Applications in Water Purification

Mussels are a widely consumed seafood; yet, most of their shells are discarded as waste. At the same time, pollution of water sources by industrial dyes like Rhodamine B (RhB) poses severe health risks. Our research addresses both issues by upcycling green mussel (Perna viridis) shells into cost-effective, reusable, and eco-friendly adsorbents for RhB removal. Using fluorescence microscopy, we characterised the interaction of RhB with the shell layers and found rapid adsorption accompanied by distinctive fluorescence. Further analysis confirmed a combined physisorption and chemisorption mechanism, with calcium carbonate as the primary adsorptive component. Sonication experiments demonstrated the reversibility of adsorption and potential for reuse. Owing to the distinctive fluorescence of RhB-adsorbed shells, our research highlights their applications as RhB biosorbents, visual biosensors, and steganographic materials. Future work will further characterise adsorption dynamics and investigate other pollutants.