Graphene/polyacrylamide interpenetrating structure hydrogels for wastewater treatment

Developing efficient, cost-effective, and environmentally friendly wastewater treatment technologies is of great significance due to the increasingly serious global environmental issue. The direct discharge of wastewater containing a large amount of harmful substances from industrial activities and daily life has severe impacts on ecosystems and human health. Therefore, this study aims to address this issue by developing a novel graphene/polyacrylamide interpenetrating network hydrogel for wastewater adsorption. By interpenetrating graphene and polyacrylamide, the advantages of both materials can be fully utilized to enhance the efficiency and performance of hydrogel wastewater adsorption. In addition, tannic acid is innovatively used as a reducing agent, not only connecting the dispersed graphene layers but also acting as a reducing agent. The hydrogel was characterized by infrared spectroscopy, surface morphology, and adsorption performance in this study. It was found that the thermal decomposition temperature of the composite hydrogel was improved with increasing the graphene content. The equilibrium water absorption capacity of the composite hydrogel was approximately 300%, and the adsorption capacity for NiCl2 was approximately 110.25 mg/g, demonstrating promising potential for practical applications. The reaction kinetics also conformed closely to the pseudo-second-order adsorption model, indicating an intraparticle diffusion model. This study provides an alternative hydrogel for treating wastewater.