Selective encapsulation of cesium ions using the cyclic peptide moiety of surfactin: Highly efficient removal based on an aqueous giant micellar system

•SF showed high affinity for Cs+ and formed their inclusion complex.•SF selectively encapsulated Cs+ even in the presence of other alkali metal ions.•A highly efficient removal of Cs+ from water using giant SF micelles was achieved through centrifugal ultrafiltration.