Eco-friendly copper nanoparticles embedded cellulose aerogel from corn husk with robust antibacterial and catalytic reduction performance

Abstract

This study aims to develop an efficient, sustainable, and cost-effective composite for antibacterial and catalytic applications. In this work, copper nanoparticles (CuNPs) was anchored onto the surface of cellulose aerogel (CA) derived from corn husk waste to create a multifunctional material. The deposition of CuNPs onto the surface of the CA is achieved using a straightforward wet reduction process of a precursor of copper (II) solution, employing glucose as both the reducing and stabilizing agent. In order to determine the characterization of the synthesized composite samples, several physicochemical analyses were investigated, including powder X-ray diffraction (XRD), Fourier transforms infrared (FT-IR) techniques, scanning electron microscopy (SEM) image, energy dispersive spectroscopy (EDS), high-resolution transmission electron microscopy (HR-TEM), and selected area diffraction (SAED). The result showed that the average size of CuNPs detected at approximately 10 ± 5 nm was immobilized and well dispersed on the CA fibers. Besides, antibacterial efficacy of cellulose aerogel decorated with CuNPs was evaluated against Escherichia coli, Bacillus cereus, Staphylococcus aureus, and Salmonella spp. using the absorption method, following the ISO 20743: 2013 standard. The results demonstrated that the antibacterial effectiveness of CuNPs varied among bacterial species, highlighting the influence of bacterial cell wall structure on CuNP susceptibility. The 2.5Cu/CA sample, containing 2.5 % CuNPs, exhibited high antibacterial activity against E. coli (99.6 %), B. cereus (99.98 %), and Salmonella spp. (88.00 %), confirming its strong potential for antimicrobial applications. In contrast, S. aureus exhibited higher resistance to CuNP treatment, with only 52.35 % bacterial reduction, likely due to its thick peptidoglycan layer, which may act as a barrier against CuNP penetration and ROS diffusion. In addition, the suitable composite 2.5Cu/CA was continually conducted to examine the catalytic activity in reducing p-nitrophenol with the presence of NaBH₄ as a reductant agent. After 5 min, the catalytic performance under the optimal condition recorded a conversion efficiency >95.0 % with an apparent rate constant of 0.789 min^-1. Therefore, these findings signify the opening of new avenues in fabricating innovative hybrid material with multiple applications in the biomedical and catalytic fields using a facile, cost-effective, and sustainable synthetic method.

Keywords: Antibacterial; Catalytic reduction; Cellulose aerogel; Dual-function material; Green synthesis; Nano‑copper.