Synthesis of hydroxyapatite (HAp) from eggshells via thermal decomposition method for the application of dye adsorption

Abstract

The study aims to synthesize hydroxyapatite (HAp) from eggshells and explore its potential for dye removal from wastewater streams. Calcium was derived from the disposed eggshells, through which CaO was acquired using the thermal decomposition technique. HAp synthesis was conducted via the direct precipitation method with the addition of diammonium hydrogen phosphate as the phosphorus source. The synthesized HAp was characterized using various techniques including XRD, SEM, FTIR, BET and UV–Vis Analysis. HAp appeared to be in a large form with tightly agglomerated rod-like nanometric particles with a surface area of 16.700 m2/g and pore volume of approximately 0.137 cm³/g, from which HAp was confirmed to have a porous structure. The synthesized hydroxyapatite showed a pure crystalline phase with a particle size in the nanometer range, according to the test results. The effectiveness of hydroxyapatite (HAp) in adsorbing methylene blue dye from wastewater was assessed using methylene blue as a representative dye. The results demonstrated that HAp exhibited a high adsorption capacity for methylene blue, indicating that the synthesized HAp was an effective adsorbent. Based on the studies conducted, it is evident that the hydroxyapatite synthesized from eggshells exhibits great potential as a cost-effective and efficient adsorbent for removing dyes from wastewater.