Mn-doped FeOOH modified g-C3N4 as a 3D tubular heterogeneous catalyst for photo-Fenton removal of organic pollutants

To develop environmentally friendly and cost-effective wastewater treatment technologies, in this study, a photo-Fenton heterogeneous catalyst Mn–FeOOH/gC3N4 with a three-dimensional porous tubular structure is prepared using a simple chemical precipitation method. Due to the loading of Mn–FeOOH, the shortcomings of graphite phased carbon nitride (g-C3N4) with rapid photogenerated carrier recombination and low specific surface area are improved. Meanwhile, the synergistic effect of Mn and Fe can promote the activation of hydrogen peroxide. In addition, the three-dimensional tubular structure can promote the absorption and refraction of visible light. Consequently, Mn–FeOOH/gC3N4 composites acquire a degradation efficiency of 97.7% at 30 min in a photo-Fenton system. The reaction rate K of Mn–FeOOH/gC3N4 is 0.11689 min−1, which is 24.6 times that of gC3N4 (0.00476 min−1). In summary, this study offers an innovative strategy for constructing 3D heterogeneous photo-Fenton composite catalysts.