Error analysis of adsorption isotherm models for acid dyes onto bamboo derived activated carbon

High surface area activated carbons were produced by thermal activation of waste bamboo scaffolding with phosphoric acid. Single component equilibrium dye adsorption was conducted on the carbons produced and compared with a commercially available carbon. Two acid dyes with different molecular sizes, namely Acid Yellow 117 (AY117) and Acid Blue 25 (AB25), were used to evaluate the adsorption capacity of the produced carbons. It was found that the dye with smaller molecular size, AB 25, was readily adsorbed onto the produced carbon, nearly three times higher than a commercially available carbon, while the larger size dye, AY117, showed little adsorption. The experimental data were analyzed using isotherm equations including Langmuir, Freundlich, Tempkin, Toth, Redlich-Peterson and Sips equations. The equilibrium data were then analyzed using five different non-linear error analysis methods.