Solid-state synthesis of green mussels (Perna viridis)-derived hydroxyapatite and perovskite nanocomposite for the photocatalytic degradation of acetaminophen

ABSTRACT: Acetaminophen (ACT) stands out as a significant emerging contaminant due to its widespread availability and global overuse. In the aquatic environment of the Philippines, ACT emerged as the second most prevalent pharmaceutical contaminant in natural waters reaching alarming levels, with readings as high as 289.17 ppb and 253.39 ppb, respectively. This study investigates the efficacy of a single-sourced hydroxyapatite-calcium titanate (Hap-CaTiO3) nanocomposite derived from waste Perna viridis (green mussel) shells for the photocatalytic degradation of acetaminophen (ACT). The waste mussel shells were utilized as a precursor for the synthesis for Hap via coprecipitation and CaTiO3 via solid state method. Subsequently, the synthesized Hap and CaTiO3 were combined to form Hap-CaTiO3 nanocomposite using solid-state synthesis. The photocatalysts were characterized using SEM-EDX, XRD and FTIR. It was observed that CaTiO3, Hap, and Hap-CaTiO3 have an average particle size of 81.78 nm, 533 nm, and 73 nm, respectively. Additionally, the FTIR analysis revealed the essential functional groups attached within the Hap and CaTiO3, while the nanocomposite has retained these functional groups from the pristine catalysts correlating to the effective formation of the heterojunction. Lastly, the XRD analysis of the Hap-CaTiO3 nanocomposite reveals the presence of both hydroxyapatite (HAp) and calcium titanate (CaTiO3) phases, with diffraction peaks matching the hexagonal structure of Hap and orthorhombic structure of CaTiO3. Average crystallite sizes of 76.05 nm for Hap, 63.54 nm for CaTiO3 and 90.17 nm for the nanocomposite provide further structural insights, collectively demonstrating successful synthesis and characterization of the Hap-CaTiO3 nanocomposite with specific phase composition and crystalline properties. Furthermore, the highest degradation efficiency for ACT was achieved at a catalyst loading of 2.5 g/L and an exposure time of 120 minutes obtaining values of 98.47%, 94.10%, and 90.96% for Hap, CaTiO3, respectively. This study presents a novel approach for utilizing waste Perna viridis shells as a precursor for a single-sourced photocatalyst. The successful synthesis and characterization of the Hap, CaTiO3, and HAp-CaTiO3, nanocomposite demonstrate their potential as a sustainable and efficient material for ACT degradation.

Filipiniana