title: The effect of granular ferric hydroxide amendment on the reduction of nitrate in groundwater by zero-valent iron.
abstract: The feasibility of using granular ferric hydroxide (GFH) with zero-valent iron (Fe(0)) for its potential utility in enhancing nitrate reduction was investigated. The addition of 10gL(-1) GFH to 25gL(-1) Fe(0) significantly enhanced nitrate removal, resulting in 93% removal of 52.2mg-NL(-1) in 36-h as compared to 23% removal with Fe(0) alone. Surface analyses of the reacted Fe(0)/GFH revealed the presence of magnetite on the Fe(0) surface, which probably served as an electron mediator for nitrate reduction. Addition of GFH to Fe(0) also resulted in lower solution pH compared to Fe(0). The rate enhancing effect of GFH on nitrate reduction was attributed to the combined effects of magnetite formation and pH buffering by GFH. GFH amendment (100gL(-1)) significantly increased reduction capacity and longevity of Fe(0) to complete several nitrate reduction cycles before inactivation, giving a total nitrate removal of 205mg-NL(-1), while unamended Fe(0) gave only 20mg-NL(-1) before inactivation during the first reduction cycle. The overall result demonstrated the potential utility of Fe(0)/GFH system that may be developed into a viable technology for removal of nitrate from groundwater.
authors.affiliation: Department of Environment and Energy, Sejong University, Seoul 143-747, South Korea.
authors.forename: Hocheol
authors.initials: H
authors.lastname: Song
authors.forename: Byong-Hun
authors.initials: BH
authors.lastname: Jeon
authors.forename: Chul-Min
authors.initials: CM
authors.lastname: Chon
authors.forename: Yongje
authors.initials: Y
authors.lastname: Kim
authors.forename: In-Hyun
authors.initials: IH
authors.lastname: Nam
authors.forename: Franklin W
authors.initials: FW
authors.lastname: Schwartz
authors.forename: Dong-Wan
authors.initials: DW
authors.lastname: Cho
mesh_terms: D000327:Adsorption; D052918:Environmental Restoration and Remediation / Q000379:methods*; D005290:Ferric Compounds / Q000737:chemistry*; D052203:Ferrosoferric Oxide; D060587:Groundwater / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D009566:Nitrates / Q000032:analysis / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry*; D018508:Water Purification / Q000379:methods
chemical_list: D005290:Ferric Compounds; D009566:Nitrates; D014874:Water Pollutants, Chemical; C021024:ferric hydroxide; D007501:Iron; D052203:Ferrosoferric Oxide
keywords: Electron mediator; Granular ferric hydroxide; Magnetite; Nitrate reduction; Zero-valent iron