Energy-efficient low-power LED-mediated effective photodegradation of cationic and anionic dyes by phthalocyanine-based COF sensitized ZnO photoactive material

Abstract

The present work involves the synthesis of 2D covalent organic framework involving zinc phthalocyanine and perylene systems (2DZnPc) as low-power LED visible-light sensitizer for ZnO nanomaterial. The synthesized materials and their composites (2DZnPc@ZnO) were characterized by Fourier transform infrared spectroscopy (FTIR), powder X-ray diffraction (XRD), Scanning electron microscopy (SEM), and Solid-state diffuse reflectance spectrophotometer to understand the structure, size, morphology, and optical properties. To examine the photodegradation competence of ZnO alone and its four different composites (2DZnPc@ZnO5, 2DZnPc@ZnO10, 2DZnPc@ZnO15, and 2DZnPc@ZnO20) in the presence of the energy-efficient low-power white LED (16 W) as source of visible light, and as modular pollutants, cationic methylene violet (MV) and anionic Eosin Y (EY) dyes were employed. The effect of different parameters on photocatalytic activity such as photocatalyst dosage, interaction time, pH of dye solution, and photocatalyst re-usage is examined. The results indicate that photosensitizing ZnO with 2DZnPc improved photocatalytic performance for the photodegradation of MV and EY dyes substantially. In an optimized environment, the removal efficiency of MV and EY was found to be 98 and 92 % respectively in 90 min.