Removal efficiency of textile dyes from aqueous solutions using calcined waste of eggshells as eco-friendly adsorbent: Kinetic and thermodynamic studies

Abstract

This research investigates the removal of textile dyes (Rhodamine B and Alizarin Red S) from aqueous solution by a low-cost adsorbent prepared from eggshell waste. Batch adsorption experiments were conducted in order to determine the effect of different parameters such as pH, dye concentration, contact time, adsorbent dosage, particle size, and temperature. The best correlation was found by Langmuir model, and the maximum adsorption capacity was 175.58 mg g-1 for Rhodamine B and 156.56 mg g-1 for Alizarin Red S. Thermodynamic studies showed that the adsorption of Rhodamine B and Alizarin Red S were feasible, spontaneous, and exothermic in nature. Regeneration study conducted to test the reusability (five cycles) and comparison of adsorption capacities of Rhodamine B and Alizarin Red S showed that calcined eggshell adsorbent could potentially be used for the removal of dyes from aqueous solutions.