Comprehensive review on the use of carrier-material-supported bimetallic nanoscale zero-valent iron to enhance nitrate removal and N selectivity

Nitrate pollution originates from wastewater discharge and agricultural and industrial activities and is becoming a serious environmental problem. Current treatment methods often need help achieving high efficiency while maintaining reasonable costs. While nano zero-valent iron (nZVI) is receiving attention as a potential chemical reduction method, challenges such as particle agglomeration, corrosion, and unwanted ammonia formation have limited its widespread application. Support materials that provide a large surface area for mass transfer, such as biochar, zeolite, layered double hydroxides, and mesoporous silica, can be used to enhance the stability, reactivity, and dispersion of nZVI. Thus, such support materials can increase the nitrate removal capacity of nZVI. The effectiveness of carrier-supported bimetallic nanoscale zero-valent iron in nitrate reduction still needs to be demonstrated more clearly to provide valuable insights to enhance nitrate treatment technology and effectively solve water quality problems. Efficient nitrate removal while ensuring high selectivity for nitrogen gas will be achieved through efforts to develop zero-valent iron-based materials to support the development of more sustainable solutions for water treatment.