OICC Press Journal of Nanostructure in Chemistry 2193-8865 11 4 (December 2021) 2021 03 08 Biosynthesis and characterization of silver nanoparticles for the removal of amoxicillin from aqueous solutions using Oenothera biennis water extract 10.1007/s40097-021-00393-x EN Robab Lotfollahzadeh Department of Chemistry, College of Science, Islamshahr Branch, Islamic Azad University, Islamshahr, IR Mohammad Yari Department of Chemistry, College of Science, Islamshahr Branch, Islamic Azad University, Islamshahr, IR Sajjad Sedaghat Department of Chemistry, College of Science, Shahr-E-Qods Branch, Islamic Azad University, Shahr-e-Qods, IR Akram Sadat Delbari Department of Chemistry, College of Science, Islamshahr Branch, Islamic Azad University, Islamshahr, IR Journal Article 2021 03 08 Abstract Oenothera biennis water extract was used to perform green nano-biosynthesis of silver nanoparticles (AgNPs) for the removal of amoxicillin (AMX) from water. Scanning electron microscopy, transmission electron microscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, and energy-dispersive analysis of X-rays were used to approve the synthesis of AgNPs. The average size of AgNPs was determined as 8.10 nm. Antibacterial activities of Staphylococcus aureus and Escherichia coli were also assessed, and the maximum inhibition zones for them were obtained as 19 and 16 mm, respectively. Experimental factors, including contact time, pH, AgNPs dosage, and initial concentration of AMX were investigated. AMX removal efficiency of 97.27% was achieved under the contact time of 30 min, pH 4, adsorbent dosage of 0.5 g, and drug concentration of 30 mg L −1 . Evaluation of the isotherm models showed that the adsorption process followed the Langmuir model ( R 2  = 0.9944) with q max  = 101.01 mg g −1 . Moreover, the kinetic studies indicated that the adsorption procedure fitted the pseudo-second-order model with R 2  = 0.9997. Graphic abstract