title: Effect of passivated iron powder on final-product distribution in Fe-supported denitrification.
abstract: An integrated nitrate treatment using passivated iron powder (PIP) and Alcaligenes eutrophus, which is a kind of hydrogenotrophic denitrifying bacteria, was conducted to investigate the effect of iron oxide coating on final-product distribution in hydrogenotrophic denitrification. Based on the results, the autotrophic denitrification supported by PIP could completely remove about 50 mg·L(-1) of nitrate within 4 days, and almost 80% of nitrate was changed into N2O (under acetylene blocking) without residual nitrite or ammonium. While only 53% of the nitrate was removed using acid-washed iron (AWI) instead of PIP, about 70% was converted into ammonium. Furthermore, a layer of FeOOH converted from hematite (α-Fe2O3) and magnetite (Fe3O4), which may block direct chemical nitrate reduction, was observed on the iron surface when PIP was used to support hydrogenotrophic denitrification. In addition, increasing pH from 5 to 8 increased nitrite generation from 1.19 to 4.91%, and decreased ammonium formation from 4.23 to 0%.
authors.affiliation: Laboratory of Agro-Waste to Resource/Scientific Observing and Experimental Station of Dali, Institute of Agro-environmental Protection, Ministry of Agriculture, Tianjin 300191, China. simon8601@gmail.com
authors.forename: Yi
authors.initials: Y
authors.lastname: An
authors.forename: Keqiang
authors.initials: K
authors.lastname: Zhang
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.forename: Qi
authors.initials: Q
authors.lastname: Dong
mesh_terms: D000421:Alcaligenes / Q000187:drug effects / Q000378:metabolism*; D058440:Denitrification / Q000187:drug effects*; D006863:Hydrogen-Ion Concentration; D007501:Iron / Q000494:pharmacology*
chemical_list: D007501:Iron