Bionanocomposite hydrogel based on carboxymethyl cellulose/xanthan gum/ZnO reinforced with Arundo donax biomass: Production, characterization, swelling study and bacterial disinfection properties in water.

Recently, the use of bionanocomposites based on polymer matrixes as a new approach for the disinfection of bacterially contaminated water has emerged as a promising alternative. Carboxymetyl cellulose (CMC) and xanthan gum (XG), natural biopolymers, were used in the present study as a semi-interpenetrating matrix reinforced with Arundo donax biomass (ADB) for the encapsulation of antibacterial ZnO nanoparticles. Hydrogel swelling decreased after ZnO nanoparticle formation, while an opposite effect was noticed for water-holding capacity of the material. The antibacterial activity of the engineered bionanocomposite was studied in dynamic mode using water samples contaminated with synthetic bacteria (gram-positive and negative). The effect of bionanocomposite dose and contact time was investigated. The results revealed that the bionanocomposite effectively neutralized all the tested bacteria, albeit with a preference for S. aureus over E. coli and P. aeruginosa. By using 1 g of bionanocomposite, a bactericidal effect was observed after 12 h for an initial bacterial concentration of 105 CFU mL-1. It should be noted that this bacterial concentration is well above the levels expected in environmental water. Hence, the CMC/XG/ADB-ZnO bionanocomposite can be considered as a potential alternative antibacterial agent for controlled water disinfection.