Novelty g-C₃N₄/HAp composite as highly effective photocatalyst for Cr (VI) photoreduction

A novelty g-C₃N₄/HAp composite photocatalyst was synthetized by precipitation and thermal condensation methods. The composite photocatalyst was studied by XRD technique confirming the presence of both phases in the composite. By FTIR and XPS techniques, the chemical bonds present in the photocatalyst and its components were analyzed. Electron microscopy shows a fine mixture of phases, preserving the lamellar structure of hydroxyapatite. The change in the optical properties of the photocatalyst was investigated by means of UV–vis spectroscopy and its photocatalytic behavior was evaluated for the photoreduction of Cr (VI) in presence of UV and visible light irradiation. g-C₃N₄/HAp composite showed an increase in its ability to reduce Cr (VI), reaching a total reduction (40 ppm solution) after 25 and 210 min for UV and visible irradiation, respectively. The increase in the photocatalytic activity can be attributed to a synergistic effect produced by the interaction between g-C₃N₄ and hydroxyapatite.