PHOTOCATALYTIC DECOMPOSITION OF RHODAMINE B DYE USING GO/PANI/CEO2 NANOCOMPOSITE

Abstract

The synthesis of efficient photocatalytic materials for the degradation of rhodamine B is important for the treatment of dye-contaminated water, as rhodamine B is a persistent synthetic dye. In this study, a GO/PANI/CeO₂ nanocomposite has been synthesized and characterized via the co-precipitation method, and its photocatalytic activity for the degradation of the Rhodamine B dye has been assessed under UV and visible-light illumination. The synthesis of the nanocomposite GO/PANI/CeO₂ was achieved by precipitation with NaOH and thermal treatment of graphene oxide, polyaniline, and cerium nitrate hexahydrate. The synthesized material was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and UV–visible spectroscopy. The photocatalytic activity was tested by using a solution of Rhodamine B under UV and visible light irradiation. The effect of the amount of catalyst and initial dye concentration was explored, and a pseudo-first-order model was used to determine the degradation kinetics. The crystallite size of the synthesized nanocomposite was estimated to be 13.75 nm, and exhibited characteristic structural features and functional properties of GO, PANI, and CeO₂. In comparison of the irradiation sources, in the process of the degradation of Rhodamine B under the condition of ultraviolet irradiation, the optimum dosage of the catalyst was 0.04 g/100 mL, and the degradation rate was about 81% after 60 min. Under the condition of visible-light, the optimum dosage of the catalyst was 0.03 g/100 mL, and the degradation rate was about 12.5% after 60 min. The degradation efficiency decreased with the progressive increase of the initial Rhodamine B concentration from 10 ppm to 30 ppm. The pseudo-first-order kinetic analysis gave an R2 = 0.99 in both UV and visible-light conditions, with reported rate constants of 2.8 × 10⁻³ min⁻¹ and 1.3 × 10⁻³ min⁻¹, respectively. The GO/PANI / CeO₂ nanocomposite exhibited significant photocatalytic activity towards Rhodamine B, especially under UV irradiation, suggesting its application for lab-scale degradation of the dye.