Removal of Remazol Black B Textile Dye from Aqueous Solution by Adsorption: Equilibrium and Thermodynamic Studies

Abstract

The use of low-cost, easy obtained, high-efficiency, and eco-friendly adsorbents has been investigated as an ideal alternative to the current expensive methods of removing dyes from aqueous solution. This study investigates the potential use of activated carbon prepared from orange peel for the removal of Remazol Black B (RB) dye from aqueous solution. It was seen that the removal of RB increased with increasing solution pH (4–10), solution temperature (25–55°C) and adsorbent dose (0.1–1 g/20 mL). The maximum dye removal was reached at 90 minutes. Adsorption isotherms were analyzed by Langmuir and Freundlich models at different temperatures of 25°C, 35°C, 45°C, and 55°C, and the results were discussed in detail. Moreover, the thermodynamics of adsorption were also studied. It was found that the values of standard free energy (ΔG°) were negative for activated carbon. The values of standard enthalpy (ΔH°) and entropy (ΔS°) were found to be positive, and the obtained results were interpreted in detail. Activated carbon developed from orange peel can be attractive options for dye removal from diluted industrial effluents since test reaction made on simulated dyeing aqueous solution show better removal percentage of RB.