image: First, graphene-like carbon nitride material (CN) was prepared using a two-step calcination method. Next, an electrostatic self-assembly strategy was employed to form covalent bonds between polyethyleneimine (PEI) and the NH2 groups on the surface of CN. Finally, Fe ions coordinated with the NH2 groups linked to PEI through covalent bonds. The XRD spectra showed that the pristine CN had two diffraction peaks at 2θ = 12.8o and 27.3o, corresponding to the (100) and (002) crystal planes of CN, respectively. After PEI modification, the characteristic peaks of 4PEI-CN almost remained unchanged. However, the introduction of Fe ions significantly weakened the two characteristic peaks of 5% Fe-4PEI-CN, indicating that the introduction of Fe ions disrupted the layered stacking structure. Meanwhile, no characteristic peaks related to iron compounds were observed, suggesting that the low-content iron was highly dispersed on CN and 4PEI-CN. In the FT-IR spectra, CN, 5% Fe-CN, 4PEI-CN, and 5% Fe-4PEI-CN all exhibited characteristic peaks of C-N bonds, triazine rings, or heptazine rings. The disappearance of the N-H bending vibration at 1651 cm-1 in both 5% Fe-CN and 5% Fe-PEI-CN confirmed the coordination relationship between Fe ions and NH2 groups.
Credit: Beijing Zhongke Journal Publising Co. Ltd.
The deep degradation of organic pollutants through solar light-coupled photocatalysis and the Fenton reaction (Photo-Fenton) holds significant importance in the field of water purification. In this study, a novel bifunctional catalyst (Fe-PEI-CN) was synthesized by electrostatic self-assembly and hydrothermal methods, doping graphene-like carbon nitride (CN) with polyethyleneimine (PEI) and iron (Fe) species. This catalyst efficiently degraded p-chlorophenol (p-ClPhOH) by generating hydrogen peroxide (H2O2) during the photocatalytic process. The relationship between catalytic efficiency and structure was explored using various characterization techniques.Under visible light irradiation, the prepared Fe-PEI-CN firstly generated H2O2 via photocatalysis and subsequently degraded the produced p-ClPhOH through the Fenton reaction, wherein Fe ions activated H2O2 to generate ·OH radicals. Due to the modification by PEI and Fe, the light absorption and excitation capabilities of CN were significantly enhanced, while the rate of photogenerated electron-hole recombination was suppressed, thereby greatly improving the photocatalytic activity. Moreover, the photocatalytic reaction also facilitated the in-situ generation of H2O2 and promoted the reduction of Fe3+ to Fe2+, further enhancing the efficiency of the Fenton reaction. The research results demonstrate that this photo-Fenton reaction exhibits highly efficient degradation of p-ClPhOH, with a maximum H2O2 production rate of 102.6 µmol/L, which is 22 times higher than that of pristine CN. The combined two-step oxidation process of photocatalytic oxidation and Fenton oxidation shows remarkable effectiveness in degrading p-ClPhOH, indicating broad application prospects in the treatment of recalcitrant organic wastewater.This study not only reveals the superior performance of Fe-PEI-CN but also provides new insights and methods for exploring the application of novel photocatalysts in environmental governance. In the future, further optimization of catalyst synthesis methods and reaction conditions may further enhance their application effectiveness in actual water treatment processes, making a greater contribution to solving water pollution problems.
See the article:
Visible Light-Induced Photocatalysis–Self-Fenton Degradation of P-Clphoh over Graphitic Carbon Nitride by a Polyethylenimine Bifunctional Catalyst
https://doi.org/10.1007/s12209-024-00386-1
Journal
Transactions of Tianjin University
Article Title
Visible Light-Induced Photocatalysis: Self-Fenton Degradation of p-ClPhOH Over Graphitic Carbon Nitride by a Polyethylenimine Bifunctional Catalyst
Article Publication Date
6-Apr-2024