Photocatalytic degradation of methylene blue dye using newly synthesized zirconia nanoparticles.

Zirconium oxide nanoparticles (ZrONPs) were prepared using the leaf extract of Muntingia calabura as a reductant. The absorption peak at 232 nm confirmed the signature peak for ZrONPs with band energy at 5.07 eV. The ZrONPs were tetragonal and highly crystalline, possessing a mean diameter of 14.83 nm as confirmed by XRD studies. The lattice constants (a = 0.362 nm and c = 0.511 nm) were consistent with the literature. Spherical nanoaggregates (29.25 nm) were seen in FESEM image and the specific signals for Zr and O were noticed in EDS image. The tetragonal phase of the ZrONPs were further confirmed from the XPS and Raman studies. PL spectrum had a sharp emission at 493 nm. The FTIR spectrum revealed the presence of various functional groups. ZrONPs were thermally stable with 5.76% total weight loss - as revealed from TGA profile. The photocatalytic breakdown of methylene blue (MB) dye under the influence of solar irradiation was performed using ZrONPs which exhibited 89.11% degradation within 5 h. Hence, the synthesized ZrONPs can be used as an alternate potential photocatalyst for the degradation of various dyes present in waste streams.