Green synthesis of Ag nanoparticles from Argemone mexicana L. leaf extract coated with MOF-5 for the removal of metronidazole antibiotics from aqueous solution.

There are growing concerns about the toxicity of metronidazole (MNZ) antibiotics in wastewater, which must be removed. This study used AgN/MOF-5 (1:3) to investigate the adsorptive removal of MNZ antibiotics from wastewater. Green synthesis of Ag-nanoparticles was from Argemone mexicana leaf aqueous extract blended with the synthesized MOF-5 in 1:3 by proportion. The adsorption materials were characterized by scanning electron microscope (SEM), N adsorption-desorption analysis, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The surface area increased due to the appearance of micropores. Besides, the efficiency of AgN/MOF-5 (1:3) for MNZ removal was evaluated by adsorption properties, including key influential parameters (adsorbent dosage, pH, contact time, etc.) and adsorption mechanism, kinetics/isotherms. The results from the adsorption process conformed to pseudo-second-order kinetics (R = 0.998) and well fitted with the Langmuir isotherm having 191.1 mg/g maximum adsorption capacity. The adsorption mechanism of AgN/MOF-5 (1:3) was due to the interactions of π-π stacking, Ag-N-MOF covalent bonding and hydrogen bonding. Thus, AgN/MOF-5 (1:3) is a potential adsorbent for the removal of aqueous MNZ. The adsorption process is endothermic, spontaneous, and feasible based on the obtained thermodynamic parameter of ΔH and ΔS having 14.72 and 0.129 kJ/mol respectively.