title: Reductive Removal of Selenate in Water Using Stabilized Zero-Valent Iron Nanoparticles.
abstract: Polysaccharide-stabilized zero-valent iron (ZVI) nanoparticles were synthesized using sodium carboxymethyl cellulose (CMC) or starch as stabilizer, and tested for reductive removal of selenate in water. Batch kinetic tests showed that the stabilized ZVI nanoparticles offer much faster selenate removal than bare ZVI particles at both pH 6.0 and pH 8.4. X-ray photoelectron spectroscopy (XPS) analyses confirmed Se(VI) was transformed to Se(IV) and Se(0), which are removed along with the nanoparticles. Neutral pH (~7) was found to be most favorable for the reductive removal. Decreasing pH to 5.0 or increasing it to 8.0 reduced the removal rate of CMC-stabilized ZVI by a factor of 4.6 or 1.3, respectively, based on the observed first-order-rate constant. Dissolved organic matter (DOM) at 5 mg/L as total organic carbon (TOC) had modest inhibitive effect, but DOM at 25 mg/L TOC decreased selenate removal by 25%. The stabilized nanoparticles hold the potential to facilitate in situ remediation of selenate-contaminated soil and groundwater.
authors.affiliation: School of Material Science and Engineering, Taiyuan University of Science and Technology, Taiyuan, Shanxi, 030024, P.R. China.
authors.forename: Hongfang
authors.initials: H
authors.lastname: Liu
authors.forename: Zhengqing
authors.initials: Z
authors.lastname: Cai
authors.forename: Xiao
authors.initials: X
authors.lastname: Zhao
authors.forename: Dongye
authors.initials: D
authors.lastname: Zhao
authors.forename: Tianwei
authors.initials: T
authors.lastname: Qian
authors.forename: Michael
authors.initials: M
authors.lastname: Bozack
authors.forename: Mingang
authors.initials: M
authors.lastname: Zhang
mesh_terms: D002266:Carboxymethylcellulose Sodium / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007501:Iron / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D009930:Organic Chemicals / Q000737:chemistry; D064586:Selenic Acid / Q000737:chemistry / Q000302:isolation & purification*; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000302:isolation & purification*
chemical_list: D009930:Organic Chemicals; D014874:Water Pollutants, Chemical; D007501:Iron; D064586:Selenic Acid; D002266:Carboxymethylcellulose Sodium