Adsorption mechanism of rare earth elements in Laminaria ochroleuca and Porphyra haitanensis

Practical applications The binding species of rare earth elements (REEs) in Laminaria ochroleuca and Porphyra haitanensis were analyzed by ICP-MS. Results showed that REEs were mainly associated with cellulose, followed by polysaccharides. Content of REEs in Laminaria ochroleuca polysaccharide was higher than that in Porphyra haitanensis polysaccharide due to its particular structure. The binding mechanism of REEs to algae was determined by desorption with three different solutions and it showed most REEs were associated with ion exchange and surface complexation. After desorption, almost all of the absorption peaks in two samples had shifted and the intensity of them had increased. Furthermore, new absorption peaks were found in Laminaria ochroleuca material after dealt with EDTA (1,334 cm(-1)) and HCl (1,735, 1,527cm(-1)), which shown that the major functional group were carboxyl, amino, sulfate, and hydroxyl in the biosorption process. All the results could be used as references to the safety evaluation of REEs in seafood. With the large-scale application of REEs, the growing release of REEs to environment is becoming a concern due to their hazard to the health of human beings. Considering the strong bioaccumulation of elements by marine organisms, it is crucial to carry out systematic safety evaluation of REEs in seafood. This work was to provide information on the characteristic of interaction between algae and REEs and illuminate the binding properties and mechanisms. This study may provide reference data for assessing potential environmental risks in seafood. Furthermore, these data would provide a basis for recycling REEs in aquatic systems.