Photocatalytic Self-Fenton System of g-C3N4-Based for Degradation of Emerging Contaminants: A Review of Advances and Prospects

Abstract

The discharge of emerging pollutants in the industrial process poses a severe threat to the ecological environment and human health. Photocatalytic self-Fenton technology combines the advantages of photocatalysis and Fenton oxidation technology through the in situ generation of hydrogen peroxide (H2O2) and interaction with iron (Fe) ions to generate a large number of strong reactive oxygen species (ROS) to effectively degrade pollutants in the environment. Graphite carbon nitride (g-C3N4) is considered as the most potential photocatalytic oxygen reduction reaction (ORR) photocatalyst for H2O2 production due to its excellent chemical/thermal stability, unique electronic structure, easy manufacturing, and moderate band gap (2.70 eV). Hence, in this review, we briefly introduce the advantages of the photocatalytic self-Fenton and its degradation mechanisms. In addition, the modification strategy of the g-C3N4-based photocatalytic self-Fenton system and related applications in environmental remediation are fully discussed and summarized in detail. Finally, the prospects and challenges of the g-C3N4-based photocatalytic self-Fenton system are discussed. We believe that this review can promote the construction of novel and efficient photocatalytic self-Fenton systems as well as further application in environmental remediation and other research fields.

Fenton-like Catalysts Based on Graphitic Carbon Nitride Nanosheets Decorated with Fe3O4 Nanoparticles for Removal of Colorless Tetracycline

“…To surmount these flaws, some protective layers in combination with the nanoparticles are required to enhance their catalytic activity. Various nanomaterials including graphene oxide, biochar, MXenes, g-C 3 N 4 , reduced graphene oxide, red mud, etc., have been utilized to fabricate effective heterogeneous Fenton-like and photo-Fenton catalysts for the abatement of toxic pollutants. ,− In a similar way, graphitic carbon nitride (g-C 3 N 5 ), an emerging nitrogen-rich metal-free carbonaceous material, is known for its beneficial bandwidth modulation and active visible-light-capturing properties . It has extended aromatic hydrogen conjugation among three heptazine units connected by tertiary nitrogen atoms.…”

Construction of a Visible-Light-Response Photocatalysis–Self-Fenton Degradation System of Coupling Industrial Waste Red Mud to Resorcinol–Formaldehyde Resin

“…Photocatalytic H 2 O 2 production is generally considered a green and sustainable model owing to the boundless supply of solar energy [14,15]. Furthermore, H 2 O 2 formed spontaneously would be activated by Fe 2+ ions to produce • OH (Fe 2+ + H 2 O 2 → Fe 3+ + • OH + OH − , k = 40-80 L•mol −1 s −1 ); the produced Fe 3+ was further reduced by photo-generated electrons, which leads to the continuous Fenton effect due to the effective acceleration of Fe 2+ /Fe 3+ that recognized rate-limiting step in the Fenton reaction (Fe 3+ + H 2 O 2 → Fe 2+ + • OOH + H + , k = 0.001-0.01 L•mol −1 s −1 ) [16,17]. In addition, the homogeneous Fenton system is limited by a narrow pH range (pH ≤ 3), and the liquid Fe-based activators are hardly separated and removed from the water body, causing secondary pollution of the purified water quality, which results in additional costs owing to the treatment of Fe mud pollution [18].…”

“…Photo-driven heterogeneous photocatalysis-self-Fenton technology offe dous superiorities in terms of economic efficiency, environmental compatibilit and pH survivability in contrast to the conventional homogeneous Fenton proc this route, H2O2 can be synthesized in situ through the semiconductor pho without the need for external additions, effectively circumventing the risks with H2O2 storage and transport. Photocatalytic H2O2 production is generally a green and sustainable model owing to the boundless supply of solar energy [ thermore, H2O2 formed spontaneously would be activated by Fe 2+ ions to pro (Fe 2+ + H2O2 → Fe 3+ + •OH + OH − , k = 40-80 L•mol −1 s −1 ); the produced Fe 3+ w reduced by photo-generated electrons, which leads to the continuous Fenton e the effective acceleration of Fe 2+ /Fe 3+ that recognized rate-limiting step in the F tion (Fe 3+ + H2O2 → Fe 2+ + •OOH + H + , k = 0.001-0.01 L•mol −1 s −1 ) [16,17]. In ad homogeneous Fenton system is limited by a narrow pH range (pH ≤ 3), and th based activators are hardly separated and removed from the water body, causi ary pollution of the purified water quality, which results in additional costs ow treatment of Fe mud pollution [18].…”

Photocatalytic Oxygen Evolution under Visible Light Mediated by Molecular Heterostructures

“…The solid worldwide energy dependence on non-renewable fossil fuels has triggered severe social and environmental problems, such as the energy crisis and global warming [1][2][3][4][5][6]. Motivated by natural photosynthesis, artificial photocatalytic systems provide promising routes to resolve energy-related problems by harnessing sunlight [7][8][9][10].…”