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Modeling selenium (IV and VI) adsorption envelopes in selected tropical soils using the constant capacitance model
Author(s) -
Gabos Mariana Bassetto,
Goldberg Sabine,
Alleoni Luís Reynaldo Ferracciú
Publication year - 2014
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.2574
Subject(s) - selenium , soil water , adsorption , environmental chemistry , capacitance , constant (computer programming) , environmental science , soil science , chemistry , organic chemistry , electrode , computer science , programming language
The adsorption of selenium (Se) on soil is important because of the relevance of Se to environmental and health issues. The adsorption of Se(IV) and Se(VI) was evaluated on soil samples from São Paulo State, Brazil, as a function of varying pH, and the experimental data were fitted to the constant capacitance model. Adsorption experiments were conducted for 15 soil samples, after the addition of 20 µmol L −1 of either Se(IV) or Se(VI), and the adjusted pH ranged between 2.5 and 10. Selenite adsorption was high for all soils, decreased with increasing pH, and was strongly correlated with Fe and Al oxide content. In contrast, Se(VI) adsorption was very low at pH values commonly found in agricultural soils, except for the highly weathered Rhodic Acrudox. The constant capacitance model fitted the Se(IV) and Se(VI) adsorption data well. Optimizations of mono‐ and bidentate complexation and surface protonation constants were used for the Se(IV) adsorption data. For Se(VI), optimizations for the 2 monodentate species were employed. Environ Toxicol Chem 2014;33:2197–2207 . © 2014 SETAC