The performance of nitrate-reducing Fe(Ⅱ)oxidation processes under variable initial Fe/N ratios:The fate of nitrogen and iron species

作     者：Boyi Cheng Yi Wang Yumei Hua Kate V.Heal Boyi Cheng;Yi Wang;Yumei Hua;Kate V.Heal

作者机构：College of Resources and EnvironmentHuazhong Agricultural UniversityWuhan430070China School of GeoSciencesUniversity of EdinburghEdinburghEH93FFUK 

出 版 物：《Frontiers of Environmental Science & Engineering》 (环境科学与工程前沿（英文）)

年 卷 期：2021年第15卷第4期

页      面：287-298页

核心收录：

学科分类：08[工学] 0815[工学-水利工程] 

基　　金：This work was supported by the National Key R&D Program of China(No.2017YFC0505305) the Fundamental Research Funds for the Central Universities(No.2662018JC053) 

主　　题：Denitrification N_(2)O emission Fe(Ⅱ)oxidation Fe/N ratio Fe minerals 

摘      要：The Fe/N ratio is an important control on nitrate-reducing Fe(Ⅱ)oxidation processes that occur both in the aquatic environment and in wastewater treatment *** response of nitrate reduction,Fe oxidation,and mineral production to different initial Fe/N molar ratios in the presence of Paracoccus denitrificans was investigated in 132 h incubation experiments.A decrease in the nitrate reduction rate at 12 h occurred as the Fe/N ratio *** nitrite concentration at Fe/N ratios of 2–10 peaked at 12–84 h,and then decreased continuously to less than 0.1 mmol/L at the end of incubation.N_(2)O emission was promoted by high Fe/N *** production of N_(2) occurred at a Fe/N ratio of 6,in parallel with the highest mole proportion of N_(2) resulting from the reduction of nitrate(81.2%).XRD analysis and sequential extraction demonstrated that the main Fe minerals obtained from Fe(Ⅱ)oxidation were easily reducible oxides such as ferrihydrite(at Fe/N ratios of 1–2),and easily reducible oxides and reducible oxides(at Fe/N ratios of 3–10).The results suggest that Fe/N ratio potentially plays a critical role in regulating N_(2),N_(2)O emissions and Fe mineral formation in nitrate-reducing Fe(II)oxidation processes.