Ternary adsorption of food dyes Acid Yellow 6 (AY-6), Acid Yellow 23 (AY-23), and Acid Red 18 (AR-18) onto activated carbon AC(op) produced from flamboyant pods (Delonix regia) was performed in this work. Derivative spectrophotometry was used for simultaneous determination of the dyes, and the response surface methodology (RSM) was applied to analyze the adsorption behavior of the three dyes onto ACop. The RSM revealed the parameters that influence the ternary adsorption of each dye: pH for AY-23, adsorption time for AR-18, and initial concentration for AY-6 and AR-18. The best experimental condition showed Q(eAY-6), Q(e.AY-23). and Q(e.AR-18) values equal to 254.493, 199.584, and 164.438 mg g(-1), respectively. AC(op) was shown to be a fast and effective adsorbent for the ternary adsorption of AY-6, AY-23, and AR-18 from aqueous solutions. (c) 2012 Elsevier B.V. All rights reserved.