Ternary adsorption of acid dyes onto activated carbon from flamboyant pods (Delonix regia): Analysis by derivative spectrophotometry and response surface methodology

Ternary adsorption of food dyes Acid Yellow 6 (AY-6), Acid Yellow 23 (AY-23), and Acid Red 18 (AR-18) onto activated carbon ACop 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 Qe,AY-6, Qe,AY-23, and Qe,AR-18 values equal to 254.493, 199.584, and 164.438 mg g−1, respectively. ACop was shown to be a fast and effective adsorbent for the ternary adsorption of AY-6, AY-23, and AR-18 from aqueous solutions.

► Ternary adsorption of food dyes on activated carbon obtained from flamboyant pods.
► Determination of dyes by derivative spectrophotometry.
► Studies of the adsorption factors by response surface methodology.