Eco-Friendly Eggshell/Silver Nanocomposite for Catalysis and Antimicrobial Use

Introduction: The increasing demand for sustainable and efficient materials has led to the synthesis of environmentally friendly nanocomposites for numerous applications. This research addresses environmental pollution and multi-drug resistant pathogens (MDR) by transforming readily available eggshell waste into a green silver-based nanocomposite. Methods: A plant-mediated synthesis was utilized to integrate the beneficial properties of eggshells with the potent antimicrobial properties of silver nanoparticles, creating a novel dualpurpose nanocomposite with improved catalytic properties and biofilm inhibitory activity. Results: This study presents a new strategy in sustainable waste management through the development of a novel dual-purpose nanocomposite. The efficient incorporation of silver nanoparticles (27.77 wt%) into the calcium carbonate structure of eggshell was confirmed using Xray diffraction analysis (XRD) and energy-dispersive spectroscopy (EDX). The nanocomposite synthesized has demonstrated excellent catalytic activity towards the reduction of 4- nitrophenol, an environmental pollutant. Moreover, it has maintained its catalytic performance through consecutive reuse cycles. In addition, the eggshell/Ag nanocomposite has demonstrated excellent antimicrobial and antibiofilm properties towards multidrug-resistant Klebsiella pneumoniae. The MIC of eggshell/Ag ranged from 18-31 μg/mL, which is much lower than that of eggshell (20-38 μg/mL). Furthermore, the eggshell/Ag nanocomposite has been found to inhibit biofilm formation effectively, with biomass values of 0.0913-0.3423 compared to 0.2917–1.16 in the control group. Discussion: Calcium carbonate matrix provides structural stability/recyclability of the resultant silver nanoparticles, with reduced susceptibility to cytotoxicity via controlled ion release. The developed material offers sustainability, dual functionality, high catalytic activity, and antimicrobial activity against drug-resistant microorganisms. Conclusion: Silver nanoparticles and eggshell integrate waste valorization with highperformance nanotechnology, resulting in excellent catalytic, antimicrobial, and antibiofilm properties. Therefore, eggshell/Ag nanocomposite has been found to be a sustainable, green nanocomposite with excellent potential for environmental cleanup and treatment of drugresistant bacteria.