Adsorption kinetics of pentachloroethane by iron-bearing smectites

被引:27
作者
Cervini-Silva, J [1 ]
Wu, J [1 ]
Stucki, JW [1 ]
Larson, RA [1 ]
机构
[1] Univ Illinois, Dept Nat Resources & Environm Sci, Urbana, IL 61801 USA
关键词
CMS clay SWa-1; CMS clay NG-1; dehydrochlorination; iron(II); iron(III); montmorillonite; nontronite; oxidation; pentachloroethane; reduction reactions; tetrachloroethene;
D O I
10.1346/CCMN.2000.0480116
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
The oxidation state of structural Fe greatly alters surface chemistry, which may have a large influence on clay-organic interactions. The effect of structural-iron oxidation state on chlorinated hydrocarbons at the clay-water interface was examined. Pentachloroethane (5CA) was reacted with oxidized, reduced, and reoxidized forms of three different smectites: montmorillonite, ferruginous smectite, and nontronite in aqueous suspension under controlled-atmosphere conditions. Pentachloroethane was found to adsorb at different rates for the three smectites. A series of 5CA-adsorption rate constants in the presence of these clays showed a strong correlation with the Fe(II) content of the clay (r2 = 0.98). The clay surface behaves as a Brønsted base and promotes 5CA dehydrochlorination. The adsorption kinetics at the clay-water interface were described by the formation of a precursor complex prior to 5CA dehydrochlorination.
引用
收藏
页码:132 / 138
页数:7
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