The first and cost-effective nano-biocomposite ZnPor/rGO/TiO2 as efficient UV photocatalysts for ethylparaben decomposition

Abstract

Organic micropollutants are considered as dangerous wastes to aquatic environments, which threaten the life of living beings. The efficacious removal of these pollutants from surrounding aquatic ecosystems has been taken into consideration in water refinery technologies. In this study, a bio-nanocomposite was developed through a green approach involving self-assembly of reduced graphene oxide (rGO) with zinc [5,10,15,20-tetrakis(2,6-dichlorophenyl) porphyrin] complex (ZnPor) and TiO₂ nanoparticles using reflux method. This organic/inorganic hybrid material was characterized using FE-SEM, XRD, EIS, RAMAN, and UV–Vis spectroscopy. The band-gap energies were found to range from 3.32 eV for GO to 2.35 eV for ZnPor/rGO/TiO₂, indicating the composites behave as semiconductor materials. The photocatalytic activity was highest for the ZnPor/rGO/TiO₂ composite based on 200 mL ZnPor addition during the synthesis process, achieving 98.1 % degradation of the model pollutant ethylparaben after only 20 min of UV treatment. The rGO facilitates electron-hole separation and transportation, while the ZnPor broadens the light absorption range and improves charge transfer. The TiO₂ nanoparticles provide the primary photocatalytic sites. These synergistic effects enhanced the photocatalytic activity of the ZnPor/rGO/TiO₂ system. This green-synthesized, eco-friendly, and highly efficient photocatalyst shows great promise for the removal of organic micropollutants from wastewater.