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Effect of SO on 1,1,1‐Trichloroethane Degradation by Fe 0 in Aqueous Solution
Author(s) -
Yu Jie,
Liu Wenxia,
Zeng Aibin,
Guan Baohong,
Xu Xinhua
Publication year - 2012
Publication title -
groundwater
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.84
H-Index - 94
eISSN - 1745-6584
pISSN - 0017-467X
DOI - 10.1111/j.1745-6584.2012.00957.x
Subject(s) - aqueous solution , chemistry , dissolution , degradation (telecommunications) , sulfate , reactivity (psychology) , reaction rate constant , inorganic chemistry , nuclear chemistry , kinetics , organic chemistry , medicine , telecommunications , physics , alternative medicine , pathology , quantum mechanics , computer science
Sulfate in groundwater has been previously shown to change the reactivity of Fe 0 in permeable reactive barriers for reducing chlorinated organics. To better understand the effect and mechanism of SO, the degradation of 1,1,1‐trichloroethane (TCA) by Fe 0 in unbuffered aqueous solutions with and without SO was investigated. In a Fe 0 ‐TCA‐H 2 O system with initial pH of 2.0 to 10.0, the maximum removal rate of TCA was achieved at the initial pH 6.0 with pseudo‐first‐order constant K obs 9.0 × 10 −3 /min. But in a Fe 0 ‐TCA‐Na 2 SO 4 ‐H 2 O system, the removal rate of TCA decreased remarkably with a reduction in K obs to 1.0 × 10 −3 /min, and the pH varied from 6.0 to 9.6, indicating an inhibition of TCA dehydrochlorination by SO. Sulfate remarkably inhibited TCA degradation via changing the route of Fe 0 dissolution. It accelerated the dissolution of Fe 0 and transformed the intermediate form Fe(OH) ads to Fe 2 (SO 4 ) ads , which weakened the affinity between Fe and TCA, and thus depressed the degradation of TCA by Fe 0 .