We report a detailed analysis of single-walled carbon nanotubes (SWCNTs) functionalized with Dimethyl Acetylenedicarboxylate (DMAD) using a large range of techniques, involving different spectroscopic analysis, transmission electron microscopy, thermogravimetric analysis, and X-ray diffraction. SWCNT functionalization is based on a simple protocol associating ultrasonication and moderate heating under endogenous pressure of the molecules to be grafted. The complete and careful characterization of the resulting grafted SWCNTs revealed that a grafting rate of more than 1 molecule per nanometer of tube length is achieved. Furthermore an original quantification of the grafting homogeneity is developed using the micro-Raman mapping technique. Sorption experiments of Cs+ ions onto grafted SWCNTs resulted in a high loading capacity, i.e. about 250 mg of Cs+ per gram of grafted carbon nanotubes, opening exciting opportunities towards the design of carbon nanotube based materials for liquid treatment applications. (C) 2014 Elsevier B.V. All rights reserved.