Phytoremediation Potential of Saccharina japonica and Sargassum horneri (Phaeophyceae): Biosorption Study of Strontium

Strontium (Sr) is an important nuclide in nuclear polluted seawater. Algal biosorption is regarded as an efficient and cost-effective way to scavenge detrimental metal ions of low concentration from polluted waters. In this study, we selected two algal species (Saccharina japonica and Sargassum horneri) through comparing background Sr contents in six algal species and explored their potential to scavenge Sr of low concentration from seawater in culture conditions. It was found that biosorption of Sr in S. japonica and S. horneri increased in response to increased Sr concentrations in the seawater and S. horneri adsorbed more Sr than S. japonica. The equilibrium established in their biosorption process follows both Langmiur and Freundlich equations well. The Sr biosorption process of S. horneri fits the pseudo-second-order kinetic model well, implying that adsorption was the rate-limiting step of the biosorption process. Results suggest S. japonica and S. horneri could become efficient biosorbents for in situ scavenging Sr from nuclear polluted seawater.