Green synthesis of hydroxyapatite cocooned nonmagnetic (Sr-Cu-MnO) nanocomposite for rapid degradation of colored organic dyes

Overviewing the ongoing increase in the demand for the environmental benign material or composite for degradation of organic dyes, we report a strategic synthesis of mixed metal nanocomposite of strontium copper and manganese oxide using Carica papaya fruit extract and encapsulating it with hydroxyapatite obtained from the fish bones (food waste). The nanocomposite was encapsulated with hydroxyapatite via using probe sonication and was characterized using XRD, SEM, TEM-EDS, FT-IR, and XPS-mapping studies. The formed encapsulated composites were subjected to photodegradation of two organic dyes viz, malachite green and aniline blue under sunlight with H₂O₂, and hydroxyapatite-encapsulated composite in catalytic amount. The degradation occurs through the Fenton process, and the surface-decorated hydroxyapatite provides surface for adsorption of the dyes and the metal oxide accompanies the degradation process. The photodegradation process is monitored using UV spectrophotometer. Theoretical mechanism has been explained considering the adsorption and individual contribution of Sr, Cu, and MnO in the composite. Rapid degradation of dyes reveals the fact that the encapsulated material has the potential to be a photocatalyst.