Adsorption of cationic basic fuchsin dye from aqueous solution using green synthesized zinc oxide coated on reduced graphene oxide nanocomposite (ZnO-rGO NC)

The removal of basic fuchsin (BF) from wastewater samples was achieved using a green synthesized zinc oxide-reduced graphene oxide nanocomposite (ZnO-rGO NC) derived from Carica papaya leaf (CPL) extract. Three adsorbents were developed and tested: zinc oxide nanoparticles (ZnO NPs), reduced graphene oxide nanoparticles (rGO NPs), and ZnO-rGO NC, across a temperature range of 50-45 degrees C. The adsorbents' performance was evaluated through batch adsorption experiments, with ZnO-rGO NC demonstrating superior efficacy among the tested materials. Key variables such as pH, adsorbent dose, dye concentration, and stirring time were investigated. The materials were characterized using Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), and transmission electron microscopy (TEM) to examine their morphological and vibrational properties. The ZnO-rGO NC achieved an 83.72% removal of BF dye, with an adsorption capacity of 110.64 mg/g, with equilibrium reached within 60 min. The adsorption process conformed to the Langmuir isotherm model and followed pseudo-second-order kinetics, indicating that the rate of adsorption controlled the process. These findings suggest that ZnO-rGO NPs hold significant potential for addressing pollution from textile dyes in wastewater. This study presents a novel approach by leveraging the synergistic effects between ZnO NPs and rGO NPs to create a ZnO-rGO NC with enhanced adsorption capabilities for the removal of BF dye from aqueous solutions.