Removal of strontium from aqueous solutions using scallop shell powder

Abstract

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 Sr 2+ , but there are currently no inexpensive Sr 2+ adsorbents with low environmental burden. We found that scallop shell powder adsorbs Sr 2+ in aqueous solutions at various initial concentrations. In this study, to obtain fundamental knowledge of the mechanism of Sr 2+ removal using waste scallop shell, we analyzed the removability of Sr 2+ . Scallop shell showed the same capacity to remove Sr 2+ at a high initial concentration ( 2 0.50 g/dm 3 ) as the reagent CaCO 3 , but a clear difference in removability appeared at a low initial concentration (0.010 g/dm 3 ), where scallop shell proved to be superior. In addition, scallop shell powder had slit-shaped pores and a specific surface area of 4.3 m 2 /g. Measurement of the adsorption isotherm in the low concentration aqueous solution showed that Sr 2+ removal occurred by chemisorption; the adsorbed Sr is present on the surface of the scallop shell powder particles.