Adsorption of basic yellow 28 (by 28) and acid yellow 23 (ay 23) dyes onto chitin

The present study investigated the sorption of Basic Yellow 28 (BY 28) and Acid Yellow 23 (AY 23) by chitin flakes. The study determined the influence of pH value on adsorption effectiveness and the adsorption capacity of chitin flakes. The results were described with Freundlich, Langmuir, Sips and double Langmuir isotherms. Similar values of adsorption capacities were achieved for both tested dyes using Langmuir, Sips and Langmuir2 models, i.e. 16.804, 17.740 and 18687 mg/g d.m. for BY28 as well as 24.195, 27.930 and 24.196 mg/g d.m. for AY23, respectively. The isotherms were compared with the use of average relative error (ARE) of approximation. In the case of both dyes, the best fit to experimental data was achieved with the use of tri-parametric Sips equilibrium isotherm, which was indicated by ARE values of 3.10% (BY 28) and 5.26% (AY 23).