Abstract:

This study investigates the adsorption of neutral red (NR) on the natural clayey material of Adilcevaz/ Bitlis located the northwest of Van Lake in Eastern Anatolia (Turkey). The adsorbent used was characterized by XRD, XRF, FTIR, SEM and TG-DTA analyzes. The effect of various parameters such as pH, contact time, initial concentration and temperature on NR removal was investigated using a batch process to optimize the maximum adsorption conditions. Equilibrium data for NR adsorption were analyzed using nonlinear two-parameter isotherms such as Langmuir, Freundlich, Dubinin-Radushkevich, and Tempkin, and three-parameter isotherm models, such as nonlinear Redlich-Peterson, Sips, and Koble-Corrigan. The modelling results showed that it was best adapted to the Freundlich isotherm model for the NR dye, with relatively higher R2 values and smaller S.E. The maximum adsorption capacity obtained from the experimental data was determined to be 4.2810 mg g-1. The adsorption process follows pseudo-second-order kinetics with a rate constant of 0.0110 g mg-1 min-1. The thermodynamic parameters indicate that a physical mechanism controls the NR adsorption on the natural clay and spontaneously occurs.

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