Eco-Friendly Activated Eggshell Adsorbent for Acid Red 87 Dye Removal: A Kinetic Study

This study investigates the synthesis and application of activated eggshell adsorbent (AESA) for the effective removal of Acid Red 87 (AR 87) dye from simulated wastewater, offering a sustainable alternative for wastewater treatment. The AESA was characterized using physicochemical analysis alongside advanced techniques including Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and Energy Dispersive Spectroscopy (EDS). The influence of adsorbent dosage on dye removal efficiency was evaluated. Kinetic adsorption data were analyzed using both linear and non-linear forms of Pseudo-First-Order (PFO) and Pseudo-Second-Order (PSO). The AESA exhibited favorable properties, including a neutral pH (7.80), moisture content (12.90%), ash content (5.80%), volatile matter (9.90%), fixed carbon (71.40%), bulk density (1.33 g/cm³), particle size (300 µm), and a high surface area (800 m²/g). These properties, particularly the high carbon content and large surface area in addition to surface functional groups, contributed to the material’s strong adsorption capacity. Dye removal was found to increase with adsorbent dosage, achieving a maximum recovery efficiency of 87.33% at an optimal contact time of 60 minutes. The adsorption kinetic was best described by the Pseudo-Second-Order model, with high correlation coefficients in both linear (R² = 0.9952) and non-linear (R² = 0.9914) regressions. Overall, the findings highlight AESA as an effective, environmentally friendly, and cost-efficient adsorbent for the remediation of dye-contaminated wastewater, promoting water reuse and environmental sustainability.