Green synthesis of Ag2O nanoparticles using Punica granatum leaf extract for sulfamethoxazole antibiotic adsorption: characterization, experimental study, modeling, and DFT calculation

Abstract

<title>Abstract</title> In this study, silver oxide nanoparticles (Ag₂O NPs) were generated by synthesizing green leaf extract of <italic>Punica granatum</italic> and used as adsorbent and used as adsorbent to remove the antibiotic additive sulfamethoxazole (SMX) from an aqueous solution. The chemical composition, surface morphology, and textural properties of the Ag₂O NPs were identified using XRD, FTIR, BET/BJH, SEM-EDX, and TEM analyses. For 100 mg L^{− 1} SMX antibiotic concentration, Ag₂O NPs achieved almost complete removal of 98.93% within 90 min by using 0.8 g L^{− 1} of adsorbent dose and initial solution pH of 4 at a temperature of 308 K. Langmuir model efficiently elucidates the experimental data, which amounts to homogeneous nature of antibiotic adsorption onto the Ag₂O NPs. The maximum uptake capacity was 277.85 mg g^{− 1}. Kinetic studies promise a PSO model. The <italic>ΔGº</italic> and <italic>ΔHº</italic> values confirm the spontaneity and endothermicity of the adsorption process. The regeneration study shows that the Ag₂O NPs can be efficiently reused for up to five cycles. The geometric structures have been optimized and quantum chemical parameters were calculated for the SMX unprotonated (SMX^+/−) and protonated (SMX⁺) using density functional theory (DFT) calculation, indicating that the SMX^+/− is reacting more favorably on the surface of Ag₂O NPs compared to the SMX⁺. According to this study, the Ag₂O NPs as an excellent potential the adsorbent will be able to have remarkable effects in the treatment of pharmaceutical wastewater.