Biosynthesis of Silver Nanoparticles from Achillea Tenuifolia Aqueous Flower Extract and Its Application for the Efficient Removal of Acid Red 18 and Methyl Orange from Aqueous Media: Isotherm and Kinetics Studies

In this study, the ability of Achillea tenuifolia aqueous flower extract was studied to synthesize silver nanoparticles (AgNPs) for the removal of Acid Red 18 (AR18) and Methyl Orange (MO) from aqueous media. UV-Vis spectroscopy, Scanning Electron Microscopy (SEM), energy-dispersive X-ray (EDX), Transmission Electron Microscopy (TEM), Fourier Transform InfraRed (FT-IR), spectroscopy and X-Ray Diffraction (XRD) analysis were used for the characterization of the prepared AgNPs. The effect of different experimental factors, including pH (3-12), adsorbent dosage (0.1-0.9 g), contact time (5-35 min), and initial concentration of dye (30-50 mg/L) was surveyed. Approximately 94% removal of dye was obtained at a pH of 3 for AR18 and 8 for MO, an adsorbent dosage of 0.9 g, a contact time of 25, and an initial concentration of 30 mg/L. The experimental data were better described by the Langmuir isotherm with the coefficient of determination (R2) of 0.9998 and 0.9995 for AR18 and MO, respectively. The maximum adsorption capacity (qmax) of 112.35 mg/g and 90.90 mg/g was obtained for AR18 and MO, respectively. The kinetic study revealed that the system fitted well with the pseudo-second-order kinetic model (R2=0.9992 for AR18, R2=0.9962 for MO). The results of this study demonstrated that synthesized adsorbent is low-cost and eco-friendly, which can be powerfully used for the removal of AR18 and MO dyes from wastewater.