Rapid development of railway industry makes safety increasingly important. Wear, contact-impact, fatigue and corrosion are important factors initiating rail track degradation from the beginning, while corrosion attracts far less attention than other issues. Direct corrosion cost due to railway corrosion in China was 18.88 billion RMB, so corrosion definitely deserves more attention. This work has reviewed studies focussing exclusively on rail corrosion, including corrosion forms, protection and detection technologies. General corrosion on large rail surface is not limiting, while crevice corrosion between rail and liner, resulting in thinning of rail foot, is regarded significant but overlooked. Moreover, reciprocating micro-motion between rail foot and liner mechanically assists the ongoing of crevice corrosion. However, it was mentioned in very few reports and not investigated extensively. Coating and surface modification may be applied for mitigation of rail track corrosion. The weakness of coating is poor mechanical properties, while surface modification, including thermal spraying and laser cladding, may be a better way. Development of novel steel is another effective method, but loss of mechanical properties becomes obstacles for practical applications. Ultrasonic and infrared have been applied for detection, while more advanced technologies are promising. Suggestions are made on specific research topics in this field.

With the discharge of large amount of organic pollutants and antibiotics into the water environment, the water cycle has been seriously polluted, and at the same time, various drug-resistant bacteria have emerged in succession, which poses a serious threat to human health. In recent years, photocatalytic nanomaterials have become a research hotspot in the antimicrobial area. In this study, AgBr/AgVO₃ photocatalysts were prepared by a hydrothermal process and an in situ growth method. The composites were tightly connected by the (501) plane of AgVO₃ and the (200) lattice plane of AgBr. The photocatalytic activity was tested by degrading Rhodamine B (RhB) solution under visible-light, and the result indicated that the photodegradation rate for RhB solution was 92.3% by the photocatalysis with 0.5AgBr/AgVO₃ and the photocatalytic performance of 0.5AgBr/AgVO₃ was improved compared to pure AgVO₃ and AgBr. In addition, more than 99.997% of E. coli, S. aureus, and P. aeruginosa cells were killed by the photocatalysis with 0.5AgBr/AgVO₃ within 30 min. These results demonstrated that the 0.5AgBr/AgVO₃ heterojunction photocatalyst could be widely used in the treatment of environmental pollution and in the antibacterial field.

Discovering novel materials and improving the properties of existing materials are the main goals in the field of photocatalysis to increase the potential application of the materials. In this paper, a modified graphitic carbon nitride (g-C₃N₄) photocatalyst named Fe³⁺-doped alkalized carbon nitride, which couples the photocatalytic reaction with the Fenton reaction, is introduced to demonstrate its Rhodamine B (RhB) degradation and antibacterial properties. Under visible-light irradiation, the degradation rate of RhB was 99.9% after 200 min, while the antibacterial rates of Pseudomonas aeruginosa (P. aeruginosa), Escherichia coli (E. coli), and Staphylococcus aureus (S. aureus) after 300 min were 99.9986%, 99.9974%, and 99.9876%, respectively. Moreover, the repetitive experiments of RhB degradation demonstrate that the proposed photocatalysts have excellent stability and reusability. The active free radical trapping experiments reveal that the superoxide radical ($·{\mathrm{O}}_2^{-}$) is the dominant reactive oxygen species. In addition, the Fenton reaction is introduced into the photocatalytic system due to the doping of Fe³⁺, and the hydroxyl radical (·OH) produced from the Fenton reaction further enhances the photocatalytic performance. The remarkable improvement in photocatalytic performance of the proposed photocatalyst can be attributed to its broader UV–visible absorption characteristic and the occurrence of the Fenton reaction.