Highly Enriched Metal Elements in Marine Biological Shells as New Resources for the Sustainable Extraction of Metals

Marine biological shell waste, as a representative renewable resource, can lead to serious environmental problems and resource waste if effective utilization methods are not developed. Therefore, there is an urgent need for innovative solutions to enable the effective recycling and reuse of marine biological shell waste. Although previous studies have explored the applications of marine biological shells in chitin extraction and animal feed production, this study is the first to reveal the possibility of obtaining metal resources from marine biological shells, which is a renewable resource available in large quantities. An analysis of the metal element concentrations in marine biological shells shows that several valuable or important metal elements are present at concentrations that are hundreds of thousands of times higher than in seawater. CaCO3 was identified as the main component for enriching metal elements in marine biological shells. The recovery efficiency of most metal elements from oyster shells could exceed 80%. This study highlights the potential of marine biological shells as a valuable metal resource, offering a sustainable approach to waste management and utilization while alleviating the risk of heavy metal accumulation and environmental pollution associated with traditional composting.