Nonmagnetic nanocomposite of strontium, copper, and manganese oxide in rapid degradation of industrial organic dyes under assistance of sunlight

Green synthesis of metal oxide nanoparticles has played a significant role in modernizing technology. In the present work, Carica papaya fruit extract has been used to synthesize a mixed metal nano composite of Sr/Cu/MnO via the coprecipitation method. The synthesized material is washed, dried, and calcined at 530 °C. The composite is analyzed using XRD, SEM, TEM, and EDS. The particle sizes are determined from XRD data, and the crystallite strain is calculated using the Willamson–Hall plot. The crystallinity index is calculated from the TEM images. The particles seem to have polycrystalline nature and hexagonal texture with surface agglomeration. The elemental presence is confirmed by EDS data. The nano-oxide mixture in catalytic amount is then used to degrade aniline blue and malachite green without the addition of any acid. Aniline blue is 74.21% degraded and malachite green is 91.07% degraded in 150 min, representing its potential as a photocatalyst. The theoretical calculation on the degradation data reveals the estimated time for 100% degradation of both dyes. Graphical Abstract