Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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Record number 551286
Title Impact of low-molecular weight organic acids on selenite immobilization by goethite: Understanding a competitive-synergistic coupling effect and speciation transformation
Author(s) Fang, Dun; Wei, Shiyong; Xu, Yun; Xiong, Juan; Tan, Wenfeng
Source Science of the Total Environment 684 (2019). - ISSN 0048-9697 - p. 694 - 704.
DOI https://doi.org/10.1016/j.scitotenv.2019.05.294
Department(s) Soil Chemistry and Chemical Soil Quality
Publication type Refereed Article in a scientific journal
Publication year 2019
Keyword(s) Adsorption - Ferric selenite - Organic acids - Reduction - Selenium - Speciation transformation
Abstract © 2019 Elsevier B.V. The interactions between low-molecular weight organic acids (LMWOAs)and selenium (Se)on mineral/water interfaces affect the release, immobilization and bioavailability of Se in nature. Herein, the effects of three environmentally relevant LMWOAs (i.e., oxalic (Oxa), succinic (Suc)and citric (Cit)acids)on Se(IV)adsorption to goethite under oxic conditions were investigated using batch experiments, speciation fractionation, and ATR-FTIR and XPS analyses. The LMWOAs exhibited a competitive-synergistic coupling effect on Se(IV)adsorption to goethite, which inhibited the adsorption rate of Se(IV)by 14.1, 13.3 and 8.0 times. However, immobilization of Se(IV)was simultaneously enhanced by 39.1%, 34.6% and 14.1% in the following order Oxa > Suc > Cit. The results obtained by fractionation of the adsorbed Se(IV)revealed that the enhancement was due to surface binding as well as speciation transformation from ligand-exchangeable Se(IV)into residual fractions, which increased by approximately 18% in the presence of the LMWOAs. The dissolution of goethite significantly improved due to the LMWOAs and decreased to different degrees as the concentration of Se(IV)increased. The monodentate mononuclear complexes (58.2%)and Lewis base sites bonded Se (41.8%)were the predominant surface species of Se(IV)in goethite-Se(IV)system. The ATR-FTIR and high-resolution XPS analyses demonstrated that the formation of ≡FeO(SeO)O-CO surface complexes (22.8–27.0%)occurred in the presence of LMWOAs, which could be closely correlated with the interface-mediated reduction of Se(IV). In addition, the predominant mechanism for the formation of residual Se is LMWOA specific, in which ferric selenite-like precipitation was dominant for Suc (10.6%)and Cit (11.6%)and reduction was dominant for Oxa (17.5%). Overall, LMWOAs play an important role in Se(IV)immobilization and speciation transformation and may facilitate understanding the Se bioavailability in rhizosphere soils under oxic conditions.
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