Photocatalytic degradation of Rhodamine B by zinc oxide nanoparticles synthesized using the leaf extract of Cyanometra ramiflora

In the current study, the green synthesis of zinc oxide nanoparticles (ZnONPs) using the leaf extract of Cyanometra ramiflora and zinc acetate precursor is presented. The phyto-components of the extract aided the reduction and the formation of nanoparticles. The purified ZnONPs were characterized by UV–Vis spectroscopy, SEM, EDS, XRD, BET, and FTIR techniques. A sharp absorption maximum at 360 nm in the UV–Vis data affirmed the formation of ZnONPs. SEM image revealed the nanoflower morphology and EDS showed strong signals for zinc and oxygen elements. XRD spectrum confirmed the hexagonal wurtzite crystalline structure of size 13.33 nm. A significant large surface area of 16.27 m²/g with mesopores, was affirmed using BET analysis. FTIR substantiated the existence of the characteristic zinc and oxygen bonding vibrations at 557 cm⁻¹, 511 cm⁻¹ and 433 cm⁻¹. The photocatalytic activity of the ZnONPs was examined using the pollutant dye, Rhodamine B. A remarkable degradation efficiency of 98% within 200 min was achieved under sunlight irradiation and a degradation constant of 0.017 min⁻¹ was obtained. Therefore, ZnONPs synthesized using a cheap and abundant source – the leaf extract of C.ramiflora possibly will play a promising part in the degradation of toxic dyes present in the wastewater.