Synergistic effect of porphyrin and NiO in chitosan/graphene oxide aerogels for enhanced photocatalytic degradation of cationic and anionic dyes

Abstract

The need for clean water has driven the search towards better ways to remove pollutants from wastewater, especially dyes from industrial sources. In this study, we introduce a novel multifunctional aerogel composite CPGNiO(5%)PyP(1%), that brings together five carefully selected components: chitosan, polyvinyl alcohol, graphene oxide, nickel oxide nanoparticles, and a porphyrin-based photosensitizer. By combining these materials, we created a porous, light-responsive system that works exceptionally well under visible light. Using a range of techniques (FT-IR, XRD, SEM/TEM, UV-vis, and XPS), we confirmed the structure and interactions within the hybrid network. When tested against two common dyes, Victoria Blue R (cationic) and Reactive Black 5 (anionic), the composite achieved impressive removal efficiencies of 96.3% and 90.5%, respectively. Further analysis showed that different reactive species (such as holes, hydroxyl, and superoxide radicals) play important roles in the breakdown process. Notably, the material could be reused across multiple cycles without significant loss of performance, and it remained effective even in mixtures of dyes. These results suggest that this composite offers a promising, scalable solution for eco-friendly water purification using visible light, an important step toward more sustainable environmental technologies.