Tailoring of Ag3PO4-Anchored Hydroxyapatite Nanophotocatalyst with Tunable Particle Size by a Facile Ion-Exchange Method for Organic Textile Dyes Photodegradation

Abstract

Silver phosphate (Ag3PO4) exhibits excellent photocatalytic performance but has limitation in its stability and reusability. To overcome the issue of reusability, composites of silver phosphate nanostructures are tailored. This paper elucidates the photocatalytic study of silver phosphate-anchored hydroxyapatite (HA) (Ca10(PO4)6(OH)2) on the degradation of commercial textile dye, Sunfix Red (SR) S3B 150% by changing the experimental parameters such as catalyst concentration, dye concentration, and pH of the dye solution under the sunlight. Silver phosphate-anchored HA (HA_Ag3PO4(x)) was prepared via a two-step process. HA was synthesized by a simple wet chemical precipitation and silver phosphate-anchored HA (HA_Ag3PO4(x)) via in situ ion-exchange method. The synthesized photocatalysts were subjected to characterization studies such as X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), ultraviolet-visible spectroscopy, and X-ray photoelectron spectroscopy (XPS). All the synthesized composites exhibited the bandgap of 2.34 eV and degraded SR in 45 min with the rate constant 0.07168 min-1 under sunlight. The trapping tests for radicals were done to study the role of free radicals in the degradation of the dye, SR, and the possible degradation mechanism was proposed. The postphotocatalytic analysis of XRD showed that the structure of Ag3PO4 remained intact declaring its structural stability. It was observed that the concentration of AgNO3 precursor influenced the number of nucleation over the surface of HA and the particle size of Ag3PO4. The applicability of the synthesized material was extended to other organic dyes such as Sunzol Black (SB) DN conc., methylene blue (MB), and rhodamine B (RhB) by the prepared composite and the findings were presented.