Colorimetric Sensing of Cd(II) Using 4-Fluorobenzohydrazide-Stabilized Silver Nanoparticles and Evaluation of Photodegradation and Antibacterial Properties.

Abstract

The alarming contamination of aquatic ecosystems with toxic heavy metals and persistent organic dyes demands innovative nanotechnological solutions for simultaneous detection and remediation. In this research, 4-fluorobenzohydrazide-stabilized silver nanoparticles (4-FBH@AgNPs) were synthesized to serve as a versatile nanoplatform for the colorimetric detection of Cd(II), photocatalytic degradation of the methylene blue (MB) dye, and antimicrobial applications. The synthesized nanoparticles were characterized using various techniques, including UV-Visible spectroscopy, FTIR, XRD, TEM, XPS, DLS, zeta potential, and SEM to assess their structural and optical properties. The UV-Vis analysis displayed a distinct localized surface plasmon resonance (LSPR) peak at 435 nm, confirming nanoparticle formation. Colorimetric sensing tests revealed notable color changes for Cd(II), showing a linear response in the nanomolar range with a low limit of detection (LOD) of 37 nM, demonstrating high sensitivity and selectivity towards Cd(II) ions. Additionally, the 4-FBH@AgNPs exhibited impressive photocatalytic efficiency, achieving over 95% degradation of methylene blue (MB) in 60 min under visible light, attributed to improved electron-hole separation and enhanced charge transfer due to plasmon effects. The nanoparticles also exhibited considerable antibacterial properties against Escherichia coli and Staphylococcus aureus. Statistical analysis affirmed the reproducibility and reliability of the photocatalytic and antimicrobial results by response surface methodology. Collectively, these findings demonstrate that 4-FBH@AgNPs possess excellent multifunctional capabilities, making them a promising candidate for environmental remediation and biosensing applications.