The biomass derived from pecan nut processing (Carya illinoinensis) for alimentary purpose, specifically the pecan shells were used in this work as a biosorbent of acid blue 74 (AB74), acid blue 25 (AB25) and reactive blue 4 (RB4). This biomass was characterized by ultimate and proximate analysis, FT-IR spectroscopy, X-ray diffraction and SEM/EDX. Adsorption studies were performed in batch and continuous systems and adsorption kinetics, isotherms and breakthrough curves were experimentally determined. Results obtained suggest that the calcium compounds occurring in pecan shells are responsible of the favorable adsorption of anionic dyes, specifically for the removal of AB74. Biosorption results showed that pecan shell is a more suitable adsorbent in dye removal processes using batch configuration rather than packed-bed columns.