Removal of Sr, Co, and Mn from seawater by Sargassum horneri in mono- and multi-nuclide contamination scenarios
The radionuclides released from the nuclear power plants (NPPs) during nuclear accidents can cause severe damage to the marine ecosystems. Strontium (Sr), cobalt (Co), and manganese (Mn) are among the main metal elements in the radionuclide wastes. Living macroalgae have been regarded as efficient materials to scavenge metal ions from polluted water bodies. Given the enormous amount of harvested Sargassum horneri biomass due to the outbreak of “golden tide” along the China’s coastline, this study aimed to evaluate its potential in removing Sr, Co, and Mn from seawater. The process, kinetics, and mechanisms of scavenging these metal elements were investigated in the present study. The interaction among these three nuclides during the removal process was also explored. The results showed that living S. horneri biomass was effective at scavenging Sr, Co, and Mn from seawater in both mono- and multi-nuclide contamination scenarios. Notably, the removal efficiency of S. horneri was found to be in the following order: Mn > Co > Sr. Furthermore, the biosorption kinetic data of living S. horneri for Sr, Co, and Mn removal were well described by both pseudo-first-order and pseudo-second-order kinetic models. The removal efficiency of S. horneri on any single nuclide could be influenced by the co-existence with other two nuclides and their concentrations.