This study provides a full characterization of ashes generated from the combustion of bagasse at two different sugarcane ethanol plants, one in the state of Pernambuco, Brazil (SBA1), and the other in Villa Clara, Cuba (SBA2), with a view to examining their usage as adsorbing agents for the removal of heavy metals and various organic impurities. The ash samples were analyzed for both chemical composition and for structural features that would aid their use. Chemical characterization was done spectrally, through the examination of X-ray fluorescence and diffraction, Fourier transform infrared spectroscopy, and thermally, through thermogravimetric and differential thermal analysis. Structural and surface characterization was carried out by examining N2-physisorption, helium pycnometry, and scanning electron microscopy. The results of each analysis were compared to those of recognized or potential adsorbent materials. Both ashes have structural similarities, heterogeneous morphologies, irregular surfaces, and a prevalence of superficial polar groups (carbonyl, carboxyl, and hydroxyl). Based on their physical and chemical characteristics, ashes could be used as adsorbent for both, organic (e.g., dyes, phenols, etc.) and inorganic (e.g., heavy metals) compounds.