Iron-based materials for nitrogen and phosphorus removal from wastewater: A review

Nitrogen (N) and phosphorus (P) pollution in water has always been a key concern for the environment. Iron, is abundant, readily available and has a variable valence, which is a vital nutrient for growth and reproduction of microorganisms. Therefore, it has beneficial effects for N and P removal. The use of iron-based materials can avoid secondary pollution caused by an additional carbon source, reduce the treatment costs and also provide good P removal. In this study, the mechanism and effectiveness of iron-based materials commonly used in wastewater for N and P removal, and their research status were summarized (Including zero-valent iron (Fe(0)), iron (hydr) oxides, iron‑carbon micro-electrolytic substrates (Fe/C-M/E) and iron sulfides, etc.). The strengths and limitations of different iron-based materials in the process of N and P removal from wastewater were discussed. Although iron-based materials can enhance N and P removal from wastewater, there are still many limitations. The combination of Fe with other materials or substances, as well as the combination of different iron-based materials, can improve material defects. Therefore, more attention should be paid to the development of new iron-based materials in the future.