Removal of strontium from aqueous solutions using scallop shell powder

抄録

It is important to efficiently remove radioactive substances contained in polluted waters before they are discharged from nuclear power plants. In particular, there is an urgent need for the development of technology that can adsorb radioactive Sr²⁺, but there are currently no inexpensive Sr²⁺ adsorbents with low environmental burden. We found that scallop shell powder adsorbs Sr²⁺ in aqueous solutions at various initial concentrations. In this study, to obtain fundamental knowledge of the mechanism of Sr²⁺ removal using waste scallop shell, we analyzed the removability of Sr²⁺. Scallop shell showed the same capacity to remove Sr²⁺ at a high initial concentration (≥0.50 g/dm³) as the reagent CaCO₃, but a clear difference in removability appeared at a low initial concentration (0.010 g/dm³), where scallop shell proved to be superior. In addition, scallop shell powder had slit-shaped pores and a specific surface area of 4.3 m²/g. Measurement of the adsorption isotherm in the low concentration aqueous solution showed that Sr²⁺ removal occurred by chemisorption; the adsorbed Sr is present on the surface of the scallop shell powder particles.