One step green synthesis of larvicidal, and azo dye degrading antibacterial nanoparticles by response surface methodology.

The present study explored the one step extracellular green synthesis of Iron oxide (Fe_xO_y) and manganese oxide nanoparticles (MnNPs) using aqueous extract of Acorus calamus rhizome. The organic chemicals including polyphenol compounds responsible for bio-reduction and stabilization from the polyphenol enriched microwave irradiated aqueous extract of Acorus calamus were studied using GC-MS analysis. Further, their synthesis conditions were optimized using response surface methodology (RSM) and central composite design (CCD) using three variables. The green synthesized Iron oxide and Manganese oxide NPs were characterized by UV, FTIR, XRD, TEM and SEM. Results indicated that the Iron oxide NPs and mixture of iron and manganese NPs showed photocatalytic excellent activities in reducing dyes like methylene blue (0.1%) and Congo red (0.25%) at 0.03% NPs. However, Mn NPs showed moderate activity. On a contrary, manganese showed better larvicidal activity compared to Iron oxide NPs against the phytopathogens commonly affecting the vegetable crops. The present finding showed that high mortality rate at 30 μg/ml concentration of manganese NPs was comparatively interesting. In addition, NPs overall had appreciable activity with P. aeruginosa being more sensitive to Iron oxide NPs (22 ± 2 mm zone of inhibition) and manganese NPs (13 ± 2 mm zone of inhibition) and Iron oxide NPs completely inhibited the growth of A. flavus at 40 μg/ml concentration.