Abstract:Nitrate (NO3-) is a common pollutant in water bodies, which can cause various damages when entering the human body. Zero-valent iron (ZVI), as an active metal, has been widely used for the reduction of NO3- due to its high efficiency, non-toxicity, low cost and abundant sources. Although ZVI has high removal efficiency for nitrate, the main product of NO3- reduction by traditional ZVI method is NH4+, which will cause secondary pollution to water bodies. And because the iron oxide formed during the reaction will inhibit electron transfer, ZVI is difficult to maintain high reactivity for a long time, and has a high dependence on pH. By developing or improving existing ZVI composite materials, and coupled with microbial processes, etc., the pH limit on the reaction and the ratio of NH4+ in the reduction product can be reduced, and its denitrification performance can be further optimized and improved. This is the current and future key research direction. This paper focuses on summarizing the effect and removal mechanism of ZVI on NO3-, expounds the effects of physical and chemical properties, pH, temperature, dissolved oxygen and other factors on the chemical denitrification efficiency of ZVI, and covers various performance enhancement measures for the reduction of nitrate by ZVI . Finally, the problems that need to be paid attention to in the actual denitrification of ZVI materials are summarized, and the future development prospects of ZVI materials are discussed and prospected.
