LAUSR

Nanoparticle synthesis from plant resources has recently gained significant impact due to its low cost, simple equipment requirements, and ease of availability. In this work, DR-AgNPs were synthesized using bark extract of Delonix regia (D. regia) plant under microwave irradiation. The formation of DR-AgNPs has been confirmed with UV-Vis, XRD, FTIR, FESEM, HRTEM, EDS, DLS, and zeta potential analysis. Catalytic and antioxidant activities were tested on synthesized spherical nanoparticles with a size range of 10-48 nm. The effects of pH and catalyst dosage on the methylene blue (MB) dye degradation were carried out. It was observed from the treatment results that 95% MB dye degradation efficiency was achieved within 4 min with a degradation rate constant of 0.772 min-1 . The synthesized nanoparticles showed a strong antioxidant property when analyzed by a 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. The calculated IC50 value for DR-AgNPs was 37.1 ± 0.12 μg mL-1 . Therefore, DR-AgNPs are excellent in both catalytic and antioxidant activities when compared to previously reported works. HIGHLIGHTS: Green synthesis of silver nanoparticles (DR-AgNPs) using Delonix regia bark extract. The catalytic activity of DR-AgNPs is remarkable against Methylene Blue. DR-AgNPs also have a strong DPPH radical antioxidant effect. Short degradation time, high degradation rate constant, and a good scavenging activity are key features of this study compared to previously reported works.