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The presence of synthetic dyes in the aquatic environment is due to industries that use dyestuffs such as textiles. Various physical and chemical techniques have been used to remove dyes. Among the methods, adsorption is a conventional process for dye removal from contaminated water. Solid waste management is also a challenge for environmental science. In the present study, plant tissues of Opuntia ficus indica cladodes were used for the removal of methylene blue (MB) from its aqueous solutions as a model compound. The plant was chosen as a cheap and abundant material in nature. The plant tissues were acid treated with HNO3 and H3PO4 to study adsorption on cactus-raw material and chemically modified (cactus-HNO3, cactus-H3PO4). The sorbents were characterized by infrared spectroscopy and ζ-potential measurements were performed to obtain the necessary information for the surface charge of the sorbents. Batch experiments were performed to construct the sorption isotherms. The experimental data were modeled by the Langmuir and Freundlich equations. The fitting was evaluated according to the correlation coefficient, R 2 . A kinetic study of adsorption was conducted to examine the effect of contact time. The influence of parameters such as the initial pH value, the sorbent dosage and the presence of inhibitory substances with the addition of NaNO3, was also studied. MB concentration was measured by UV-Vis spectrophotometry. It was found that the three adsorbents are suitable for the removal of ΜΒ from aqueous solutions with sorption capacities 67.8 mg/g, 70.2 mg/g και 68.8 mg/g for cactus-raw, cactus-H3PO4 and cactus-HNO3 respectively