g-C3N4/MnO2 coated cotton fabric as effective dip-catalyst for organic dyes degradation via persulfate activation

Abstract

The purpose of this study is to assess the catalytic efficiency of a new catalyst, MnO₂@g-C₃N₄-CF, for the advanced oxidation-based degradation of organic pollutants. Manganese oxide (MnO₂) and graphitic carbon nitride (g-C₃N₄) make up the active catalyst, while cotton fabric (CF) serves as an inert support. The catalyst was prepared by sonicating g-C₃N₄ onto the CF, followed by deposition of MnO₂ nanoparticles, resulting in the effective and sustainable “dip catalyst” MnO₂@g-C₃N₄-CF. The synthetized materials, including g-C₃N₄, MnO₂, and MnO₂@g-C₃N₄-CF were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS). The composite was tested for its ability to oxidize organic dyes, including methyl orange (MO), congo red (CR), malachite green (MG) and rhodamineB (RhB), using an enhanced oxidation process with persulfate acting as an oxidant. Furthermore, the effects of a several parameters on the degradation kinetics were carefully investigated, including pH, composite surface, MnO₂ loading (%), persulfate, and MO concentration. After 60 min of the reaction, a removal efficiency of 84 % of MO was achieved, using a (3 cm × 3 cm) MnO₂@g-C₃N₄-CF surface. The synthesized composite demonstrated remarkable durability, maintaining consistent catalytic activity without any notable decline even after five reaction cycles. Additionally, it was demonstrated that the principal reactive oxidative species (ROSs) responsible for the highly efficient degradation of MO were SO₄^•− and •OH. Finally, the catalyst durability and reuse revealed the fact that MnO₂@g-C₃N₄-CF could be used as a heterogeneous catalyst for dyes oxidation and environmental remediation.