Synthesis and characterization of HAp/MgPO₄ Nanocomposites from Green Mussel Shell as potential adsorbent

Universitas Negeri Malang, Chemistry Department, 65145, Malang, Indonesia

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Abstract

This study aimed to synthesis and characterization material HAp/MgPO4 as an adsorbent for wastewater analysis using the precipitation method on green mussel shell waste (biogenic Ca source) and characterized by XRD, FTIR, SEM-EDX, UV-Vis and AAS. Calcination at 800-1000 °C yielded a pure HAp phase (COD 9011091) with increasing crystallinity at higher temperature (95.86 %). FTIR confirmed HAp characteristic bands (PO ^3-, OH⁻) and some carbonate inclusion, indicating successful HAp formation. SEM-EDX revealed porous aggregates (4-100 nm) with a dominant Ca, P, Mg, O composition. XRF of raw shells showed Ca 96.3 %, rising to 98.6 % CaO after calcination. AAS measurements of filtrate showed Ca²⁺ release of 56.7, 154.1, and 50.1 ppm for samples calcined at 800, 900, and 1000 °C (highest at 900 °C). The results of UV-Vis measurements showed that the absorbance (A) and concentration (ppm) values changed with increasing temperature. At 800°C, the highest absorbance value was 1.28 with a concentration of 0.332 ppm, while at 900°C the absorbance value decreased to 1.11 with a concentration of 0.287 ppm. At 1000 °C, the absorbance value increased slightly to 1.12 with a concentration of 0.290 ppm. These structural features suggest effective adsorption of Fe²⁺/Ni²⁺. Green mussel-derived HAp/MgPO4 thus offers an eco-friendly, high-purity adsorbent.