Catalytic reduction of p-nitrophenol and methylene blue by microbiologically synthesized silver nanoparticles.

Abstract Catalytic Reduction of p-nitrophenol and Methylene blue by Microbiologically Synthesized Silver Nanoparticles was studied in the present investigation. Catalytic reduction of 4-Nitophenol/p-nitrophenol (PNP) and methylene blue (MB) was assessed using both intra and extracellular silver nanoparticles (AgNP) with and without immobilization. Both intracellular and extracellular AgNP were synthesized from actinomycetes. Antimicrobial activity of AgNP was also assessed and it was found that, intracellular AgNP have significant antibacterial activity against E. coli , S. typhi and B. subtilis. Synthesized biogenic silver nanoparticles were characterized by UV–visible spectrophotometry, FTIR, XRD, and TEM-EDS. It was found that, extracellular AgNP are efficient as compared to intracellular AgNP in terms of PNP reduction. Graphical abstract Unlabelled Image Highlights • Extracellular silver nanoparticles have excellent catalytic activity in reduction of p-nitrophenol. • Immobilized intra and extracellular AgNPs have good methylene blue reduction ability. • The XRD pattern confirms the face centered cubic (fcc) structure of nano silver. • TEM images reveal the presence of multidispersive nanosilver with varying size 4.7 nm, 6.8 nm and 18.8 nm with mean particle size 10.1 nm and exhibiting roughly spherical morphology. [ABSTRACT FROM AUTHOR]