Biosorption of Sr2+ and Cs+ onto Undaria pinnatifida: Isothermal titration calorimetry and molecular dynamics simulation

• Published in: Journal of molecular liquids 2020-12, Vol.319, p.114146, Article 114146
• Main Authors: Hu, Yuming, Guo, Xuan, Wang, Jianlong
• Format: Article
• Language: English
• Subjects: Algal sorbent; Biosorption; Cesium; Molecular stimulation; Radionuclide; Strontium
• ISSN: 0167-7322; 1873-3166
• DOI: 10.1016/j.molliq.2020.114146

In this paper, the biosorption of strontium and cesium ions onto a marine brown alga Undaria pinnatifida (also known as wakame), was studied using isothermal titration calorimetry and molecular dynamics simulation. Different adsorption performance of cesium and strontium ions was evaluated. The adsorption kinetics of cesium and strontium ions followed to pseudo second-order and pseudo first-order models, respectively. The maximum adsorption capacity was 1.10 and 2.17 mmol g−1 for cesium and strontium ions, respectively, calculated by the Sips isotherm. The main active sites for metal ion adsorption were carboxyl, sulfate, amine and amide. The isothermal titration calorimetry indicated that strontium ion was more competitive than cesium ion for binding sodium alginate. The molecular dynamics simulation revealed a stronger interaction energy between sodium alginate and strontium ion than that of cesium ion. This study revealed underlying mechanisms of different performances of cesium and strontium adsorptions by both experimental and computational approaches, suggesting the potential application of Undaria pinnatifida for adsorptive removal of cesium and strontium ions from aqueous solution. [Display omitted] •The biosorption of Cs+ and Sr2+ by a marine algae U. pinnatifida was evaluated.•Carboxyl, sulfate, amine groups were involved in the adsorption process.•Isothermal titration calorimetry showed that Sr2+ was more competitive to binding alginate.•Molecular dynamics simulation revealed a stronger interaction between alginate and Sr(II).