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Se(IV)/Se(VI) adsorption mechanisms on natural and on Ca-modified zeolite for Mediterranean soils amended with the modified zeolite: prospects for agronomic applications.
- Source :
-
Environmental science and pollution research international [Environ Sci Pollut Res Int] 2023 Mar; Vol. 30 (14), pp. 41983-41998. Date of Electronic Publication: 2023 Jan 14. - Publication Year :
- 2023
-
Abstract
- In the present study, the ability of a modified CaCl <subscript>2</subscript> zeolite (Ca-Z) to both increase Se(IV) availability and restrict Se(VI) mobility in soils is examined. As it was resulted from batch experiments and verified by X-ray absorption fine structure (XAFS) and X-ray fluorescence (XRF) spectroscopies, higher amounts of both Se species adsorbed on Ca-Z compared to natural zeolite (Z-N) forming outer-sphere complexes while the oxidation state did not alter during agitation of samples. Thereafter, Ca-Z was incorporated in six Greek soils, divided into acid and alkaline, at a 20% (w/w) rate and a series of equilibrium batch experiments were performed with soils alone and soils-Ca-Z mixtures to investigate sorption and desorption processes and mechanisms. The acid soils, either treated with Ca-Z or not, adsorbed higher amounts of Se(IV) than alkaline ones, whereas soils alone did not adsorb Se(VI) but impressively high adsorption of Se(VI) occurred in the Ca-Z-treated soils. Desorption of Se(IV) was higher from the Ca-Z-treated soils and especially from the acid soils. Higher distribution coefficients of desorption than the distribution coefficients of sorption were observed, clearly pointing to a hysteresis mechanism. The experimental data fitted with Langmuir and Freundlich isotherms. In the presence of Ca-Z, the Langmuir q <subscript>m</subscript> values increased indicating higher Se(IV) retention while Langmuir b <subscript>L</subscript> values decreased suggesting lower bonding strength and higher Se(IV) mobility. Overall, treating the soils with Ca-Z increased Se(IV) adsorption and mobility whereas it provided sites for Se(VI) adsorption that did not exist in the studied soils.<br /> (© 2023. The Author(s).)
- Subjects :
- Soil chemistry
Adsorption
Agriculture
Zeolites
Soil Pollutants analysis
Subjects
Details
- Language :
- English
- ISSN :
- 1614-7499
- Volume :
- 30
- Issue :
- 14
- Database :
- MEDLINE
- Journal :
- Environmental science and pollution research international
- Publication Type :
- Academic Journal
- Accession number :
- 36640241
- Full Text :
- https://doi.org/10.1007/s11356-022-24979-2