Sustainable green-synthesized hematite nanocatalysts and their efficient reduction of aromatic nitro pollutants

Abstract

Aromatic nitro compounds (ANCs) are extremely harmful environmental pollutants that cause severe threats to the environment and human life. This is why the development of effective and non-polluting methods for their elimination is extremely significant. In this study, hematite nanoparticles (HNPs) were prepared using a green and eco-friendly method involving the leaf extract of Sesbania grandiflora. The extract of the plant acted as a reducing and stabilizing agent in the formation of the nanoparticles, making it a cost-effective and sustainable synthesis pathway. The obtained HNPs were identified by UV-vis spectroscopy, FTIR spectroscopy, PXRD, HRTEM and EDAX analysis to ascertain the structural and morphological characteristics of the synthesized nanoparticles. The prepared HNPs were tested as catalysts towards the reduction of different aromatic nitro compounds. Kinetic measurements showed that the reduction followed pseudo-first-order kinetics and that mono-nitro compounds reduced much faster in this system than in traditional reduction systems. Moreover, the catalyst was very stable and recyclable and could sustain high catalytic activity for up to six consecutive reaction cycles. The results prove that green-synthesized HNPs can act as effective nanocatalysts for the removal of nitroaromatic pollutants from contaminated water systems.