Agricultural wastes have shown to be efficient adsorbents for the treatment of dissolved pollutants.In this research, the adsorption of the indigo blue dye (IB) on rice husk (RH) was evaluated and RH bromatological and structural characterizations were carried out.A 2 3 full factorial design allowed to achieve a 90.0%IB removal at pH = 2.0, initial IB concentration of 30 mg/L, RH dosage of 8.0 g/L, contact time of 4 h and at 65°C.Further optimization of the process through a central composite surface design led to a minimal increase in efficiency, with a maximum removal of 92.0%.As for the adsorbent characterization, the infrared spectrum showed that the most important bands correspond to the associated hydroxyl group (3,300 cm -1 ) and silicon oxide (750 and 1,020 cm -1 ), whereas scanning electron microscopy indicates a uniform surface composed of concave cells.These results suggest that RH is an effective adsorbent for the removal of IB, whose treatment is recognized as difficult due to its poor solubility.