SUSTAINABLE FABRICATION OF MULTIFUNCTIONAL MAGNETIC SCHIFF BASE NANOHYBRIDS FOR HEAVY METAL REMOVAL AND ANTIBACTERIAL APPLICATIONS

Abstract

With the growing incidence of heavy metal contamination and multidrug-resistant bacterial 
infections, materials with multiple functionalities and those that are friendly to the environment 
are required to solve both problems together. A green and sustainable method was used to 
prepare magnetic Schiff base nanohybrids, via the functionalization of Fe₃O₄ magnetic 
nanoparticles with bioactive Schiff base ligands, synthesized by condensation of naturally 
occurring aldehydes and amines. Successful surface functionalization, high crystallinity, 
excellent magnetic recoverability, and a large number of active adsorption sites were confirmed 
by UV–Visible spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR), X-ray 
Diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy 
(TEM), Energy-Dispersive X-ray Spectroscopy (EDS), Vibrating Sample Magnetometry 
(VSM), Brunauer–Emmett–Teller (BET) surface area analysis, and X-ray Photoelectron 
Spectroscopy (XPS).The adsorption efficiency of the magnetic Schiff base nanohybrids was 
systematically investigated for the adsorption of toxic heavy metal ions (Pb(II), Cd(II), Cr(VI) 
and Cu(II)) under various experimental conditions. Based on the synergistic effect of magnetic 
separation and the Schiff base metal-chelation functionality, the nanohybrids showed fast 
adsorption rate, high adsorption capacities and good removal efficiencies. Langmuir isotherm 
and pseudo-second-order kinetic model were applied to the adsorption behavior, which was 
found to be closely followed, suggesting that the dominant monolayer chemisorption process 
was predominant. At the same time, the nanohybrids showed excellent antimicrobial activity 
against Staphylococcus aureus and Escherichia coli, creating zones of inhibition, low minimum 
inhibitory concentration (MIC) and effectiveness against biofilm formation by inducing the 
production of reactive oxygen species (ROS) which caused disruption of the bacterial cell 
membranes and intracellular oxidative stress. In addition, the nanohybrids showed very high 
structural stability, magnetic recyclability and remained over 90% active towards the 
adsorption and antibacterial activity after multiple regeneration cycles, which indicated their 
long term operational stability. Efficient removal of heavy metals, strong antibacterial 
properties, environmental-friendly synthesis, and easy magnetic recovery make these 
multifunctional magnetic Schiff base nanohybrids highly promising materials in integrated 
environmental remediation, wastewater purification, antimicrobial coatings, and sustainable 
biomedical applications. The results represent a good alternative design for next generation 
multifunctional magnetic nanomaterials that can help simultaneously solve both environmental 
pollution and microbial contamination problems. 

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