The impact of ammonia concentration and reducing agents on the ammonia oxidation performance of embedded nano-FeCu

Abstract

Study on ammonia oxidation using nano-FeCu is very limited. NaBH4 is commonly used reducing agent for nanoparticle synthesis and regeneration, but it is toxic and costly. Thus, the objectives of this study are to investigate the performance of embedded nano-FeCu (eFeCu) in treating varied concentration of ammonia polluted water and identify the optimum dosage of FeCu for ammonia oxidation. The use of Na2CO3 as the replacement for NaBH4 is also investigated. Result showed that eFeCu converted ammonia to nitrogen gas when it was exposed to ammonia solution. Conversion from nitrate and nitrite to ammonia was observed in the first hour of reaction when eFeCu was exposed to <50 ppm ammonia solution. High dosage of FeCu improved the ammonia removal rate, but it is not cost-effective. At the optimum condition, eFeCu oxidised ~45% and ~37% of ammonia when it was reduced by NaBH4 and Na2CO3 respectively. However, the regeneration cost of NaBH4 was ~2.45 times higher than Na2CO3. Stability study showed that eFeCu was stable, where the leaching of both Fe2+ and Cu2+ complied with Standard A. In conclusion, FeCu could be an alternative to treat ammonia polluted water and Na2CO3 is a green and cost-effective reducing agent for eFeCu regeneration.