Optimizing calcium materials for minimizing arsenate phytoavailability in upland arable soil based on geochemical analysis.
J Hazard Mater
; 448: 130927, 2023 Apr 15.
Article
in En
| MEDLINE
| ID: mdl-36764253
This study aimed to evaluate the reducing effects of calcite and phosphogypsum on arsenate [As(V)] availability to plants and elucidate the mechanisms of As(V) immobilization. The concentration of available As(V) to plants in upland arable soils with 1% calcite and phosphogypsum decreased to 17.4% and 36.9%, respectively, compared to the control. As(V) phytoavailability depends on the soil pH and calcium materials. The process of stabilizing As(V) (F3; anion exchange) with phosphogypsum is faster and easier compared to that with calcite (F4; bind to carbonate), but it results in a less stable form. New Ca-As(V) minerals (Ca52(HAsO4)x(AsO4)âyH2O, Ca5H2x(AsO4)âyH2O, or Ca32(AsO4)â10 H2O) were identified in X-ray diffraction (XRD) patterns with calcite treatment. Precipitation, the primary mechanism induced by calcite, was activated at a soil pH above 8.0. Based on the deconvolution of calcium and sulfur X-ray photoelectron spectroscopy spectra and the peak shift in the XRD pattern in phosphogypsum, the substitution in which SO42- is exchanged with HAsO42- is the primary mechanism for As(V) immobilization. Substitution induced by phosphogypsum is a suitable reaction in upland arable soils, the predominant form of As(V) in the soil, with a pH range of 5-7.
Full text:
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Collection:
01-internacional
Database:
MEDLINE
Language:
En
Journal:
J Hazard Mater
Year:
2023
Document type:
Article