Green gamma-irradiated chitosan/PVA–silver hydrogel for efficient methylene blue removal

Abstract In the context of increasing water pollution by organic dyes, the development of environmentally friendly materials with effective treatment capabilities is urgently needed. This study aimed to synthesize a biodegradable nAg-CS/PVA hydrogel with high compatibility for dye adsorption applications. The dual gamma irradiation technique successfully synthesized nAg-CS/PVA hydrogel material from the immobilization of nAg-CS particles (particle size of 24.95 nm, a polydispersity index of 0.202, and zeta potential of + 20.7 mV) into the PVA polymer network. The formation of nAg-CS/PVA was confirmed by FTIR, DSC, and FESEM analyses, which showed that the strong interaction between the functional groups of chitosan and PVA, combined with the superior complexation ability of Ag, contributed to the enhancement of gelation and swelling properties. The synthesized hydrogel was applied to remove methylene blue (MB) with a maximum adsorption capacity (q m ) of 285.71 mg g −1 under optimal conditions (PVA solution 150 g l −1 , PVA:nAg-CS volume ratio of 8:2 and irradiation dose of 30 kGy). The neutron activation confirmed the successful immobilization of Ag nanoparticles, ensuring the minimal release of silver ions into the environment. These findings highlight the potential of nAg-CS/PVA hydrogel as an efficient and environmentally friendly material for the treatment of dye-contaminated wastewater.