Fig. 11

a Surface functionalization of the GO sheet by covalent and non-covalent interactions. b Membrane performance of laminated GO and GO-COOH under the equal condition [99]. Adapted with permission from ref [99]. Copyright 2017 for Elsevier. c Na⁺ ion permeation through 0.9 μm-thick EDTA-GO and EDTA-rGO membranes (insert: 1 μm-thick EDTA-GO membrane) [101]. Adapted with permission from ref [101]. Copyright 2016 for Nature Publishing Group