Biocompatible Dual-Functional NiO-rGO@CMC Composite Hydrogel for Pathogen Disinfection and Dye Degradation During Wastewater Remediation

In this study, a hydrogel materials incorporating nickel oxide (NiO) nanoparticles and reduced graphene oxide (rGO) into carboxymethyl cellulose (CMC) were developed and evaluated for its dual-functional efficacy in bacterial disinfection and methylene blue (MB) dye degradation. The hydrogel materials were investigated by FTIR, XRD, SEM, TEM, XPS and TGA, which revealed that the CMC matrix displayed effectively incorporated NiO nanoparticles and rGO. Under visible light irradiation, MB dye was photocatalytically degraded to 100% elimination in 120 min, with rGO facilitating improved electron transport and reduced charge recombination. We evaluated the antibacterial characteristics of NiO-rGO@CMC hydrogel through the Well diffusion experiment and assays for bacterial inactivation. The findings indicated its significant efficacy against certain pathogenic microorganisms. The hydrogel completely killed all bacteria in 75 to 120 min, with Gram-negative bacteria being inactivated faster than Gram-positive bacteria. The hydrogel's effectiveness under real-world wastewater conditions was confirmed by disinfection trials performed with a laboratory-scale reactor. These trials led to a significant reduction in bacterial populations over time, and ultimately in complete disinfection for all tested strains. In a toxicological evaluation, the Microtox 500 analyzer confirmed that the hydrogel was biocompatible, had no toxic properties, and produced no harmful degradation products. In conclusion, this research proves that the NiO-rGO@CMC hydrogel is a reliable, efficient, and green alternative to wastewater treatment and remediation since it eliminates dyes and disinfects the water without harming the environment.