High-performance catalytic degradation of rhodamine 6G dye by NiO/Reduced graphene oxide nanocomposite from the wastewater system

Organic dyes have been serious concern for the environment from last few decades which pose several health hazards. Amongst the organic dyes rhodamine 6G (Rh 6G) is a synthetic dye and known to be carcinogenic for human and other organism. This research has been carried out to prepare an effective photocatalyst NiO-rGO nanocomposite and used for the degradation of Rh 6G. The as prepared NiO-rGO nanocomposite was characterised through X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and atomic force microscope (AFM) instruments to evaluate its crystalline structure, elemental composition, 3D texture and morphology. The prepared material exhibited nanometric size of 43.8 nm with excellent crystalline structure and phase purity. Moreover, SEM and AFM analysis revealed nanocube like texture which are imbedded in rGO sheets. The NiO-rGO photocatalyst was applied for degradation of Rh 6G. Under the optimised condition of 7.0 mg catalyst dose, 5 min reaction time under the sunlight and 25 µL of reducing agent, the NiO-rGO photocatalyst manifested exceptional degradation up to 97.8%. Moreover, for the reusability study the experiment under optimised parameters was repeated for seven times. After 7th cycle the degradation efficiency prepared catalyst was reduced from 97 to 68 % which highlighted that prepared catalyst can be exploited for several time for degradation of Rh 6G. The overall research suggested that the Rh 6G NiO-rGO photocatalyst can be a promising candidate for removal of organic economically at large scale with high efficiency and minimal dose.