2020, Vol. 8, Issue 1, Part A

author(s)
Afrina Ara Ahmed and Pranab Dutta

abstract
Silver nanoparticles (Ag NPs) were synthesized using culture filtrate of fungal antagonist Trichoderma asperellum for which silver nitrate was used as the precursor. The Ag NPs thus formed were then characterized by using UV-Vis spectrophotometer, Dynamic Light Scattering (DLS), Zetasizer, Transmission Electron Microscope (TEM) and Energy Dispersive X-Ray Analysis (EDX). The UV-Vis spectroscopy showed a characteristic Surface Absorption Band at 420 nm which confirmed the formation of silver nanoparticles. DLS and TEM study revealed the uniform and well-dispersed nature of the biosynthesized nanoparticles with a spherical shape. The average particle size recorded was 8.26 nm with polydispersity index of 0.857. The charge of silver nanoparticles determined by zeta sizer had a negative potential value of -1.34 mV which indicated stability on dispersion. EDX results showed biosynthesized material contained 32.18% silver, 10.16% oxygen, and 57.66% carbon. The silver nanoparticles were applied at 100% concentration to the collected soil samples from tea garden and a few soil parameters viz. soil pH, soil microbial count, soil organic carbon and soil microbial biomass carbon were evaluated in both treated and untreated soil samples. All the parameters showed increased values, except, the soil microbial count which was seen decreased, in the Ag NPs treated soil samples.