Exploring the Adsorption Performance of Eggshell Powder for Methylene Blue Removal from Wastewater

This study investigates the potential of eggshell (ES) powder as a sustainable and low-cost adsorbent for the removal of methylene blue (MB) dye from aqueous solutions. Batch adsorption experiments were conducted to evaluate the effects of pH (2, 7, and 12), contact time (0–45 minutes), and adsorbent dosage (0–40 g/L) on MB removal efficiency. The ES powder was prepared through drying, grinding, and ball milling, and characterized using SEM, FTIR, and particle size analysis. UV–Vis spectrophotometric measurements indicated that MB adsorption was highly pH-dependent, with maximum removal observed under alkaline conditions (pH 12), achieving nearly complete dye removal within 45 minutes. The adsorption efficiency increased rapidly in the first 5 minutes, followed by a gradual plateau as equilibrium was approached. Increasing ES dosage enhanced dye removal up to a saturation point around 10 g/L. FTIR spectra confirmed interactions between MB and ES, particularly under alkaline conditions, supporting the role of electrostatic attraction. Overall, the findings demonstrate that ES is an effective, eco-friendly adsorbent for MB removal, especially under basic pH, making it a promising candidate for wastewater treatment applications.