Adsorption of reactive black 5 dye using eggshell waste supported by Fe2O3: An equilibrium isotherms study

Annually, the textile industry discharges thousands of tons of non-dissolved dyes into water bodies, presenting significant environmental challenges. Eggshell waste has emerged as a valuable, low-cost, and environmentally friendly adsorbent for addressing these issues. This study investigates the adsorption of Reactive Black 5 dye using eggshell waste supported by Fe2O3, focusing on equilibrium isotherms to evaluate the adsorption capacity. The synthesized adsorbent was characterized using SEM, XRD, FTIR and BET analyses, revealing the spherical morphology and substantial surface area of Fe2O3, which contributed to enhanced adsorption efficiency. XRD confirmed the crystalline structure of the eggshell waste. Adsorption data fit best with the Langmuir isotherm model, demonstrating a maximum adsorption capacity of 250 mg/g for the removal of Reactive Black 5 dye. The combination of eggshell waste with Fe2O3 presents an efficient and sustainable solution for dye removal from wastewater, promoting both environmental protection and the reutilization of waste materials. © 2025 The Authors