The synthesis of sustainable nanomaterials for water remediation is vital for overcoming the toxic byproducts associated with conventional disinfection. Silver nanoparticles (AgNPs), and alginate-silver nanoparticles nanocomposites (Alg-AgNc) in the form of beads were synthesized by a green approach using the aqueous extract of green spinach leaves. The rich phytochemicals present in the extract played a dual role as reducing and capping agents producing stable nanoparticles with a strong surface plasmon resonance (SPR) peak at 387 nm. The kinetics of formation was monitored by ultraviolet-visible (UV-Vis) spectroscopy, and the spectra were analysed using Lorentzian function. Structural and morphological characterization by Transmission Electron Microscopy (TEM) and Selected Area Electron Diffraction (SAED) confirmed the formation of crystalline AgNPs. The synthesized nanoparticles were immobilized into alginate beads through ionotropic crosslinking, resulting in nearly spherical composites with an average diameter of 1.22 mm. Energy Dispersive X-ray (EDX) spectroscopy revealed a AgNPs loading of 4.2 wt% on the surface and 7.4 wt% in the interior of the beads. The Alg-AgNc beads demonstrated exceptional catalytic efficiency achieving more than 90% degradation of Congo red dye and 2-nitrophenol within 30 minutes. The beads exhibited robust reusability with no significant loss in performance over five consecutive cycles. The beads exhibited potent, dose-dependent antibacterial disinfection against Escherichia coli , Pseudomonas aeruginosa , and Staphylococcus aureus .
Zakwani et al. (Sun,) studied this question.