Green synthesized licorice-root-based SiNH₂@FeNP nanocomposite for efficient removal of priority pollutant atrazine:...

The widespread agricultural use of atrazine (ATRZ), a persistent triazine herbicide, poses significant ecological and human health risks, classifying it as a priority substance under the EU Water Framework Directive. In this study, an eco-friendly SiNH₂@FeNP nanocomposite was synthesized via a green chemistry approach utilizing licorice root (Glycyrrhiza glabra) extract as a reducing and stabilizing agent. The structural layout of the synthesized nanocomposite was verified based on established FTIR, XRD, SEM-EDX, and BET benchmarks from our previous baseline reports, confirming a porous matrix with a specific surface area of 256.1 m² g^-1. The adsorptive removal of ATRZ from aqueous solutions was systematically optimized using the Response Surface Methodology (RSM) based on a Box-Behnken design, evaluating the interactive effects of pH (4-8), initial ATRZ concentration (2-10 mg L^-1), and adsorbent dosage (0.5-4 g L^-1). Analysis of variance (ANOVA) validated a significant quadratic model (F-value = 8.23) for ATRZ removal. The optimal operational conditions were determined as pH 6.06, an initial ATRZ concentration of 9.49 mg L^-1, and an adsorbent dosage of 0.65 g L^-1. Equilibrium data were well described by the Freundlich isotherm model, and the adsorption kinetics followed pseudo-second-order dynamics (R ² > 0.98), indicating a chemisorption controlled process. These findings provide a foundational proof-of-concept, demonstrating that the green-synthesized SiNH₂@FeNP nanocomposite is a promising laboratory-scale material for the targeted removal of priority pesticide contamination. Under these optimum coordinates, the predicted atrazine removal efficiency and equilibrium adsorption capacity were fully corroborated by independent experimental validations, achieving a maximum experimental capacity of ∼14.8 mg g^-1.