Green synthesis of silver nickel bimetallic nanoparticles using plant extract of Salvadora persica and evaluation of their various biological activities

Abstract

Metallic nanoparticles play vital role in the field of science, medicine, food and technology. Various strategies have been used for the synthesis of bimetallic nanoparticles to improve the physical and chemical properties of monometallic nanoparticles. The present study describes synthesis of Ag-Ni bimetallic nanoparticles, using aqueous extract of Salvadora persica. Silver and nickel ions were reduced by secondary metabolites within the extract which act as reducing as well as capping agents. UV–visible spectrum produced an absorbance band in the range of 400 nm to 450 nm due to electronic transitions associated with resonance of surface electrons that was an indication of the formation of nanoparticles. Scanning Electron Microscopy (SEM) and x-ray diffraction spectroscopy (XRD) were used for the determination of morphology and dimension of nanoparticles. Particle dimension of synthesized nanoparticles was 23.67 nm. Energy dispersive x-ray spectroscopy (EDX) was used for the elemental analysis that showed the presence of silver and nickel in elemental form. Fourier Transform Infrared Microscopy (FTIR) was used for the functional group analysis. Synthesized Ag-Ni bimetallic nanoparticles were assessed for the estimation of their antioxidant potential by three methods i.e. DPPH free radical scavenging mechanism, phosphomolybdenum complex method and determination of phenolic contents. Percent scavenging activity of synthesized Ag-Ni bimetallic nanoparticles was observed as 70.5% at 1500 μg ml−1 concentration. Total antioxidant activity calculated for synthesized nanoparticles was 0.6479 against BHT as a reference. Total phenolic contents of green synthesized nanoparticles were calculated to be 74.5 mg g−1 GAE. Different parameters like temperature, pH, effect of adsorbent concentration, time of contact, and concentration of adsorbate, were optimized for the utmost removal of congo red dye and chromium (VI).