Green Synthesis of Silver Nanoparticles using Delonix regia Extract, Characterization and its Application as Adsorbent for Removal of Cu (II) Ions from Aqueous Solution

Abstract

In this research synthesis of silver nanoparticles by a green method is studied. The high importance of silver nanoparticles using extract of Delonix regia (DREAgNs) is due to their unique properties, such as non-expensive, easily available and have application in water treatment. Synthesized silver nanoparticles AgNPs were characterized using UV-Visible Spectrophotometer to indicate the synthesis of AgNPs by green methods. The maximum absorbance of UV-Vis. analysis at wavelength 464 nm. (FT-IR) spectra to indicate the functional groups of phytochemical compounds at Delonix regia extract (DRE) and the silver nanoparticles (DREAgNPs) and also shows the role of active chemical constituents in stabilization and reduction of (DREAgNPs). Based on the transmission electron microscopy image analyses (TEM) confirmed the formation of spherical DREAgNPs with a particle size range of 20-50 nm with an average particle size of 35 nm. The Cu2+ ion adsorption process was studied by (DREAgNPs). The Cu2+ ions removal efficiency (R. E.) is 88.4 %   at an initial concentration 15 ppm. Removal efficiency (R. E.) decreases as the Cu2+ ion concentration increases.  Furthermore, thermodynamic studies confirmed that the biosorption process was endothermic and the positive value of ΔG° is quite common when an ion-exchange mechanism applies in the biosorption. The Positive value of ΔS◦ suggested an increase in randomness during the biosorption. The Freundlich isotherm has a good fit with the experimental data (R2 =0.99) compared to Langmuir isotherm (R2 = 0.90). This study shows that DREAgNPs are available, low cost, effective and environment friendlly biosorbent for the removal of Cu2+ ions from aqueous environment.