Equilibrium Kinetics and Thermodynamic Studies of the Adsorption of Tartrazine and Sunset Yellow

Batch adsorption experiment was carried out on freema (combination of Tartrazine and Sunset Yellow) an adsorbent prepared from moringa pod. The adsorption capacity of the adsorbent was determined. Effect of such factors as initial concentration of the adsorbate solution, contact time with the adsorbent, pH of the dye solution, and temperature of the dye solution on the adsorption capacity of the absorbent was determined. The result showed that the optimum adsorption was attained at pH of 3, adsorption equilibrium was attained within 60 min. The adsorption capacity increases with increase in initial concentration of the dye solution. The result of the kinetics study showed that the adsorption process was better described by the pseudo-second order rate equation. The adsorption process fitted well with both Freundlich (R2 = 0.983) and Langmuir (R2 = 0.933) models. Thermodynamic result showed ΔH and ΔS were all negative. Gibbs free energy change (ΔG) increases with increase in temperature of the dye solution.