Zinc phthalocyanine polyamide/PANI functionalized ZnO photocatalyst for the photodegradation of organic dyes using LED white light

Abstract

In this study, tetra-amine zinc phthalocyanine (TAZnPc) was polymerised with pyromellitic dianhydride, followed by treatment with zinc oxide nanoparticles (ZnO) and polyaniline (PANI) to form a zinc phthalocyanine polyamide/PANI functionalized ZnO nanohybrid (PolyZnPc/PANI@ZnO). Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and solid-state diffuse reflectance spectroscopy (SsDRS) were performed to analyse the structural, morphological, and optical characteristics of the synthesised materials. The photochemical efficiency of PolyZnPc/PANI@ZnO in the degradation of water pollutant dyes such as Methylene Blue (MB) and Eosin Yellow (EY) in the presence of a low-powered 16 W LED white light source. The efficiency of the photocatalyst was determined by varying parameters such as the effect of the pH of the dye solution, dosage of the photocatalyst, interaction time, and photocatalyst re-usage. The newly developed catalyst exhibited 14 times higher activity than the pristine ZnO photocatalyst. Under the irradiation of LED white light, 20 mg of PolyZnPc/PANI@ZnO could degrade 98.1 % of MB at pH 10 and 93.9 % of EY at pH 7 in 90 min. The photosystem followed pseudo-first-order kinetics in the photodegradation process, with superoxide and hydroxyl radicals as major reactive species, with a moderate influence of holes.