Biogenic synthesis of Agricultural Waste-Derived ZnO/Ag Nanocomposites for Bifunctional Applications in Antimicrobial and Wastewater Remediation

Abstract

The development of advanced nanomaterials through the value-adding of agricultural waste has gained interest due to the increasing need for sustainable solutions to environmental pollution and microbial resistance. The synthesis of multifunctional nanocomposites from agricultural waste, specifically banana peel biochar, is studied in this work. It is incorporated with zinc oxide (ZnO) and silver nanoparticles (AgNPs) to develop a hybrid nanocomposite (BPB-ZnO/Ag). Through intensive characterisation employing FTIR, XRD, SEM-EDX, and BET analyses, the synthesised material was found to have a mesoporous structure, a large surface area (128.7 m²/g), and a uniform distribution of nanoparticles—all of which contribute to its increased reactivity. The nanocomposite performed quite well in both functions. BPB-ZnO/Ag's broad-spectrum antibacterial efficacy was confirmed in antimicrobial testing by showing notable inhibition zones against Staphylococcus aureus (19.5 mm) and Escherichia coli (21.3 mm). Under visible light irradiation, the nanocomposite demonstrated a 97.8% photodegradation efficiency of methylene blue dye in 80 minutes for wastewater remediation. Additionally, textile effluent samples showed a significant 83.4% decrease in COD. Its operational stability was demonstrated by reusability tests, which showed over 85% efficiency after five consecutive cycles. The potential of agricultural waste-derived nanocomposites as inexpensive, eco-friendly acceptable materials for multipurpose environmental applications is highlighted by this work. By turning agricultural waste into high-performance nanomaterials, this research promotes waste circularity, reduces pollution, and the improvement of sustainable nanotechnology.