Investigation of Adsorption Capacity of Acid Yellow Dye onto Activated Ermenek (Karaman-Turkey) Region Lignite

Abstract

All materials such as coal, lignite, wood, bone, coconut shells, nut shells, rice husks and various fruits seeds could be used in water treatment as an adsorbent. Activated carbon is obtained by the process of carbonization fallowed by activation of the initially carbonaceous material. The product of the carbonization process, i.e. of pyrolysis of the carbon containing material, conducted in the absence of air and any chemicals, is a material virtually inactive with regards to adsorption, with a specific surface area of several m²/g. In this study, The activated Ermenek lignite (EAC) was used to adsorption experiments at different conditions (pH, initial dye concentration, mass of adsorbent, shaking speed, contact time). The aim of this work is to investigate acid yellow 194 dye adsorption capacity of the natural lignite found around Konya. The sorption capacities of EAC were obtained as 10.9 mg/g for acid yellow 194.

Freundlich and Langmuir isotherms for the adsorption of methylene blue dye on EAC were measured to establish the mechanism for dye adsorption. Freundlich isotherm constants, n (Freundlich exponent related to adsorption intensity) and  (Freundlich constant related to adsorption capacity of adsorbent) were determined as 9.34 and 6.85 (mg/L) (L/mg)ⁿ, respectively. Langmuir isotherm constants, (maximum possible amount of component per unit weight of adsorbent to form a complete monolayer on the surface bound) and (constant related to the affinity of the binding sites) were determined as 10.44 mg/g and 0.71 L/mg, respectively. R² values of Freundlich and Langmuir isotherms were determined as 89% and 98%, respectively.