Determination of the Efficiency, Isotherm, and Kinetics of Color Absorption of Sunset Yellow FCF from Aqueous Solution by Granular Activated Carbon

Introduction and purpose: Sunset yellow FCF is a hazardous azo dye pollutant found in food processing effluent. In this study, the efficiency of granular activated carbon on the absorption of sunset yellow FCF from aqueous solution, as well as isotherm and absorption kinetics were evaluated.Methods: This experimental laboratory study was conducted to investigate the effect of independent parameters such as pH, contact time, adsorbent dose, and initial concentration on the removal percent of sunset yellow FCF. The absorbance of the specimens was read three times by a spectrophotometer apparatus at the wavelength of 480 nm. In this study, the Langmuir and Freundlich adsorption isotherm models were used for mathematical modeling of the sunset yellow color adsorption process. Additionally, the pseudo-first- and pseudo-second-order kinetics equations were used for data analysis.Results: The contact time played a greater role in the adsorption process than either pH or initial dye concentration. By increasing contact time from 5 min to 50 min, the dye removal efficiency increased from 62% to 85%. When the weight of the adsorbent increased from 1 g to 8 g, the dye removal efficiency increased from 65% to 82%. Freundlich isotherm models could describe the adsorption equilibrium of the dye onto the granular activated carbon. Freundlich isotherm represented a better correlation compared to other isotherms (R2>0.9998). Moreover, pseudofirst- order models fit well with the experimental data (R2>0.9975)