Novel photo-Fenton nanocomposite catalyst based on waste iron chips-Ti3C2Tx MXene for efficient water decontamination

The Ti3C2Tx MXene is a novel two-dimensional (2D) material with unique optical properties and excellent water dispersibility related to rich surface termination. This study uses its properties to design an innovative magnetic catalyst made of waste iron chips (WI), surface-modified with a 2D Ti3C2Tx MXene. We further utilize it to advance a heterogeneous Fenton process for industrial dye removal. Novel WI-MXene nanocomposite catalyst overcame difficulties associated with the acidic pH range, frequently required for efficient generation of reactive oxygen species (ROS) via Fe (II) activity. The photo-active 2D MXene enabled the WI-MXene catalyst activation in the visible light range and near-neutral pH with excellent performance in decomposing model organic dye methylene blue (MB). The novel catalyst showed over 95 % efficiency in decomposing MB upon UV light irradiation at pH = 5 and about 62 % in decomposing the total organic carbon (TOC). Since the WI-MXene had a band gap of about 1 eV, it also showed a tunable activity toward specific light ranges. The irradiation with 550 nm (cyan) light gave the highest photo-Fenton efficiency. Analysis of the fundamental process mechanism showed a massive ROS evolution and a minor adsorption activity of WI-MXene toward decomposed dye. The post-process stability analysis did not show any changes in the WI-MXene structure. Further regeneration of spent WI-MXene enabled its reuse with 90 % efficiency at various pH values. Collectively, the obtained results show a high potential for MXene-enabled photo-Fenton processes.