Facile synthesis of a biopolymer/biomass-based nanocomposite hydrogel encapsulating silver nanoparticles for water disinfection
摘要
Controlled disinfection of genetically tolerant micro-organisms has been a challenging task, although microorganisms have been widely claimed to be one of the most common trace contaminants in drinking and surface water. In response to this challenge, our research described in the present paper a novel disinfection procedure whereby silver nanoparticles (AgNPs) were synthesized in-situ within a cross-linked matrix based on a mixture of biopolymers (carboxymethyl cellulose and xanthan gum) and Arundo donax biomass waste (CXB@AgNPs). The antimicrobial action of this material against three model bacteria (Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa) were revealed to be highly effective, achieving elimination degrees of 93.3%, 85.1% and 88.4%, respectively, at a microbial concentration of 105 CFU mL−1 over 6 h. The disinfecting performances of CXB@AgNPs nanocomposite was improved both by increasing the contact time (2 h to 12 h) and the nanocomposite quantity (0.25, 0.5, 1.0 and 2.0 g). The main mechanism implicated the release of the active agent, Ag+, and the subsequent generation of reactive oxygen species (•OH, •O2− and H2O2). Compared with free AgNPs, the CXB@AgNPs hydrogel provides distinct advantages for water purification: the cross-linked biopolymeric network reduces nanoparticle aggregation, ensures controlled Ag+ release, and minimizes secondary contamination. In addition, the use of renewable biopolymers and agricultural biomass waste makes the material low-cost, sustainable, and environmentally friendly. Owing to its effective antimicrobial performance, stability of immobilized nanoparticles, and eco-safe design, CXB@AgNPs emerges as a highly promising candidate for practical and sustainable water disinfection applications.