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Reductive Removal of Selenate in Water Using Stabilized Zero‐Valent Iron Nanoparticles
Author(s) -
Liu Hongfang,
Cai Zhengqing,
Zhao Xiao,
Zhao Dongye,
Qian Tianwei,
Bozack Michael,
Zhang Mingang
Publication year - 2016
Publication title -
water environment research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.356
H-Index - 73
eISSN - 1554-7531
pISSN - 1061-4303
DOI - 10.2175/106143016x14609975746929
Subject(s) - zerovalent iron , selenate , nanoparticle , chemistry , water treatment , selenium , zero (linguistics) , environmental chemistry , nuclear chemistry , environmental engineering , materials science , environmental science , nanotechnology , adsorption , organic chemistry , linguistics , philosophy
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.