Abstract

GREEN SYNTHESIS OF SILVER NANOPARTICLES FROM TETLEY TEA WASTE FOR Fe³⁺ DETECTION, PHOTO CATALYTIC DYE DEGRADATION, AND ANTIBACTERIAL APPLICATIONS

K. Chandra Rekha*, Y. B. Nagamani

Abstract

Green synthesis of silver nanoparticles (Ag-NPs) has emerged as an environmentally sustainable alternative to conventional chemical methods due to its simplicity, safety, and cost-effectiveness. In the present study, silver nanoparticles were successfully synthesized using Tetley tea powder waste extract as a natural reducing and stabilizing agent without the use of any additional chemical reagents. The developed method is rapid, non-toxic, economical, and suitable for sustainable large-scale production while promoting the reutilization of tea waste. The formation of Ag-NPs was confirmed by the appearance of a characteristic surface plasmon resonance (SPR) absorption peak at approximately 420 nm in the UV–Visible spectrum. The synthesized nanoparticles were comprehensively characterized using FTIR, XRD, DLS, SEM, and TEM techniques. FTIR analysis confirmed the involvement of phytochemicals present in the tea extract during nanoparticle synthesis and stabilization, while XRD analysis established the crystalline nature of the Ag-NPs. SEM and TEM images revealed predominantly spherical nanoparticles with sizes ranging from 10 to 30 nm, and DLS analysis indicated good colloidal stability. The synthesized Ag-NPs exhibited selective colorimetric sensing toward Fe³⁺ ions, demonstrating their potential for monitoring iron contamination in water samples. In addition, the nanoparticles showed efficient photocatalytic degradation of crystal violet dye under irradiation and significant antibacterial activity against both Bacillus subtilis and Escherichia coli, with comparatively higher efficacy against the Gram-positive strain. These findings demonstrate that Tetley tea powder waste-derived AgNPs are multifunctional nanomaterials with promising applications in environmental monitoring, wastewater treatment, and antimicrobial technologies.

Keywords: Green synthesis; Silver nanoparticles; Tetley tea powder waste; Surface plasmon resonance; Fe³⁺ ion detection; Photocatalytic degradation; Crystal violet dye; Antibacterial activity; Environmental remediation.