Visible-Light-Driven Reduced Graphite Oxide as a Metal-Free Catalyst for Degradation of Colored Wastewater

Reduced graphite oxide (rGO)-based materials have demonstrated promising potential for advanced oxidation processes. Along with its distinctive 2D characteristics, rGO offers the prospect of catalytic degradation of various kinds of organic pollutants from aqueous environments. The practical application of rGO as a metal-free catalyst material to promote the Fenton reaction depends on the degree of rGO reduction. In this regard, the rGO was prepared according to oxidation by modified Hummers' method and two-step reduction via hydrothermal and calcination in the N-2 atmosphere. The as-prepared rGO was characterized in terms of X-ray diffraction, Fourier-transform infrared spectroscopy, thermal gravimetric analysis, scanning electron microscopy, UV-vis absorption spectroscopy, and transmission electron microscopy. The effectiveness of as-prepared rGO as a photocatalyst and the metal-free catalyst to decolorize different textile dyes, including basic red 46, basic red 18, and methylene blue, was investigated in visible/rGO and visible/rGO/H2O2 systems. The impact of operational factors such as catalyst dose, pH, and initial dye concentration was examined. The dye degradation process was investigated by the pseudo-first-order kinetic model. In addition, the recyclability of rGO in the visible/rGO/H2O2 system was examined.

Automated summary

Reduced graphite oxide (rGO) materials have shown great potential in advanced oxidation processes for the catalytic degradation of organic pollutants in water. The application of rGO as a metal-free catalyst in the Fenton reaction depends on its degree of reduction. This study prepared rGO using the modified Hummers' method and two-step reduction via hydrothermal and calcination processes. The effectiveness of as-prepared rGO as a photocatalyst and metal-free catalyst for decolorization of various textile dyes was investigated, and factors such as catalyst dose, pH, and initial dye concentration were examined. The recyclability of rGO in the photocatalytic system was also examined.