Preparation of a mesoporous Cu–Mn/TiO2 composite for the degradation of Acid Red 1

Abstract

Heterogeneous catalysts which show high catalytic performance, structural stability, and low toxicity, are greatly required to efficiently degenerate organic pollutants in waste water in advanced oxidation processes (AOPs). In this paper, a mesoporous Cu–Mn/TiO₂ composite heterogeneous catalyst was successfully prepared, which has a stable crystalline TiO₂ mesostructure as the support, and well-dispersed Cu–Mn oxides as the catalytic active sties. Its Cu, Mn content is measured to be 5.7 and 6.0 wt%, and the BET surface area is measured to be 97 m² g⁻¹ with a pore size of ∼6.0 nm and pore volume of 0.15 cm³ g⁻¹. Using the prepared Cu–Mn/TiO₂ composite as an AOPs catalyst for the degeneration of Acid Red 1, it can efficiently (>99%) degenerate the model pollutant in water within only 90 min. Compared with homogeneous catalysts, it can retain its catalytic performance over a wide pH range (3–9) and can be recycled for at least five times while still possessing the decolorization efficiency of 89%. By analyzing the catalytic process, a possible catalytic procedure for the degradation of Acid Red 1 has been proposed. Furthermore, using bulk Cu–Mn oxides, Cu–Mn/P25, and Cu–Mn/SBA-15 as reference catalysts, we propose that the excellent catalytic performance of Cu–Mn/TiO₂ could be ascribed to the anatase mesoporous TiO₂, which not only offers a stable matrix with high surface area for Cu–Mn catalysts, but also serves as a type of catalytic promoter for the synergistic catalytic degeneration of Acid Red 1.